Down integrate from Google internal.

58 files changed, 5886 insertions, 2081 deletions

diff --git a/java/core/src/main/java/com/google/protobuf/AbstractMessage.java b/java/core/src/main/java/com/google/protobuf/AbstractMessage.java
index 9f418f2b..03c0d579 100644
--- a/java/core/src/main/java/com/google/protobuf/AbstractMessage.java
+++ b/java/core/src/main/java/com/google/protobuf/AbstractMessage.java
@@ -50,17 +50,23 @@ import java.util.Map;
  *
  * @author kenton@google.com Kenton Varda
  */
-public abstract class AbstractMessage extends AbstractMessageLite
-                                      implements Message {
+public abstract class AbstractMessage
+    // TODO(dweis): Update GeneratedMessage to parameterize with MessageType and BuilderType.
+    extends AbstractMessageLite
+    implements Message {
+  
+  @Override
   public boolean isInitialized() {
     return MessageReflection.isInitialized(this);
   }
 
 
+  @Override
   public List<String> findInitializationErrors() {
     return MessageReflection.findMissingFields(this);
   }
 
+  @Override
   public String getInitializationErrorString() {
     return MessageReflection.delimitWithCommas(findInitializationErrors());
   }
@@ -83,12 +89,14 @@ public abstract class AbstractMessage extends AbstractMessageLite
     return TextFormat.printToString(this);
   }
 
+  @Override
   public void writeTo(final CodedOutputStream output) throws IOException {
     MessageReflection.writeMessageTo(this, getAllFields(), output, false);
   }
 
   protected int memoizedSize = -1;
 
+  @Override
   public int getSerializedSize() {
     int size = memoizedSize;
     if (size != -1) {
@@ -288,8 +296,8 @@ public abstract class AbstractMessage extends AbstractMessageLite
    * other methods.
    */
   @SuppressWarnings("unchecked")
-  public static abstract class Builder<BuilderType extends Builder>
-      extends AbstractMessageLite.Builder<BuilderType>
+  public static abstract class Builder<BuilderType extends Builder<BuilderType>>
+      extends AbstractMessageLite.Builder
       implements Message.Builder {
     // The compiler produces an error if this is not declared explicitly.
     @Override
@@ -314,6 +322,7 @@ public abstract class AbstractMessage extends AbstractMessageLite
       throw new UnsupportedOperationException("clearOneof() is not implemented.");
     }
 
+    @Override
     public BuilderType clear() {
       for (final Map.Entry<FieldDescriptor, Object> entry :
            getAllFields().entrySet()) {
@@ -322,14 +331,22 @@ public abstract class AbstractMessage extends AbstractMessageLite
       return (BuilderType) this;
     }
 
+    @Override
     public List<String> findInitializationErrors() {
       return MessageReflection.findMissingFields(this);
     }
 
+    @Override
     public String getInitializationErrorString() {
       return MessageReflection.delimitWithCommas(findInitializationErrors());
     }
+    
+    @Override
+    protected BuilderType internalMergeFrom(AbstractMessageLite other) {
+      return mergeFrom((Message) other);
+    }
 
+    @Override
     public BuilderType mergeFrom(final Message other) {
       if (other.getDescriptorForType() != getDescriptorForType()) {
         throw new IllegalArgumentException(
@@ -407,6 +424,7 @@ public abstract class AbstractMessage extends AbstractMessageLite
       return (BuilderType) this;
     }
 
+    @Override
     public BuilderType mergeUnknownFields(final UnknownFieldSet unknownFields) {
       setUnknownFields(
         UnknownFieldSet.newBuilder(getUnknownFields())
@@ -415,17 +433,19 @@ public abstract class AbstractMessage extends AbstractMessageLite
       return (BuilderType) this;
     }
 
+    @Override
     public Message.Builder getFieldBuilder(final FieldDescriptor field) {
       throw new UnsupportedOperationException(
           "getFieldBuilder() called on an unsupported message type.");
     }
 
-    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field,
-        int index) {
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
       throw new UnsupportedOperationException(
           "getRepeatedFieldBuilder() called on an unsupported message type.");
     }
 
+    @Override
     public String toString() {
       return TextFormat.printToString(this);
     }
@@ -462,7 +482,7 @@ public abstract class AbstractMessage extends AbstractMessageLite
     @Override
     public BuilderType mergeFrom(final ByteString data)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data);
+      return (BuilderType) super.mergeFrom(data);
     }
 
     @Override
@@ -470,20 +490,20 @@ public abstract class AbstractMessage extends AbstractMessageLite
         final ByteString data,
         final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data, extensionRegistry);
+      return (BuilderType) super.mergeFrom(data, extensionRegistry);
     }
 
     @Override
     public BuilderType mergeFrom(final byte[] data)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data);
+      return (BuilderType) super.mergeFrom(data);
     }
 
     @Override
     public BuilderType mergeFrom(
         final byte[] data, final int off, final int len)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data, off, len);
+      return (BuilderType) super.mergeFrom(data, off, len);
     }
 
     @Override
@@ -491,7 +511,7 @@ public abstract class AbstractMessage extends AbstractMessageLite
         final byte[] data,
         final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data, extensionRegistry);
+      return (BuilderType) super.mergeFrom(data, extensionRegistry);
     }
 
     @Override
@@ -499,13 +519,13 @@ public abstract class AbstractMessage extends AbstractMessageLite
         final byte[] data, final int off, final int len,
         final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data, off, len, extensionRegistry);
+      return (BuilderType) super.mergeFrom(data, off, len, extensionRegistry);
     }
 
     @Override
     public BuilderType mergeFrom(final InputStream input)
         throws IOException {
-      return super.mergeFrom(input);
+      return (BuilderType) super.mergeFrom(input);
     }
 
     @Override
@@ -513,7 +533,7 @@ public abstract class AbstractMessage extends AbstractMessageLite
         final InputStream input,
         final ExtensionRegistryLite extensionRegistry)
         throws IOException {
-      return super.mergeFrom(input, extensionRegistry);
+      return (BuilderType) super.mergeFrom(input, extensionRegistry);
     }
 
     @Override
diff --git a/java/core/src/main/java/com/google/protobuf/AbstractMessageLite.java b/java/core/src/main/java/com/google/protobuf/AbstractMessageLite.java
index 12384983..43736dd1 100644
--- a/java/core/src/main/java/com/google/protobuf/AbstractMessageLite.java
+++ b/java/core/src/main/java/com/google/protobuf/AbstractMessageLite.java
@@ -43,9 +43,13 @@ import java.util.Collection;
  *
  * @author kenton@google.com Kenton Varda
  */
-public abstract class AbstractMessageLite implements MessageLite {
+public abstract class AbstractMessageLite<
+    MessageType extends AbstractMessageLite<MessageType, BuilderType>,
+    BuilderType extends AbstractMessageLite.Builder<MessageType, BuilderType>> 
+        implements MessageLite {
   protected int memoizedHashCode = 0;
-
+  
+  @Override
   public ByteString toByteString() {
     try {
       final ByteString.CodedBuilder out =
@@ -59,6 +63,7 @@ public abstract class AbstractMessageLite implements MessageLite {
     }
   }
 
+  @Override
   public byte[] toByteArray() {
     try {
       final byte[] result = new byte[getSerializedSize()];
@@ -73,6 +78,7 @@ public abstract class AbstractMessageLite implements MessageLite {
     }
   }
 
+  @Override
   public void writeTo(final OutputStream output) throws IOException {
     final int bufferSize =
         CodedOutputStream.computePreferredBufferSize(getSerializedSize());
@@ -82,6 +88,7 @@ public abstract class AbstractMessageLite implements MessageLite {
     codedOutput.flush();
   }
 
+  @Override
   public void writeDelimitedTo(final OutputStream output) throws IOException {
     final int serialized = getSerializedSize();
     final int bufferSize = CodedOutputStream.computePreferredBufferSize(
@@ -120,25 +127,27 @@ public abstract class AbstractMessageLite implements MessageLite {
    * other methods.
    */
   @SuppressWarnings("unchecked")
-  public static abstract class Builder<BuilderType extends Builder>
+  public abstract static class Builder<
+      MessageType extends AbstractMessageLite<MessageType, BuilderType>,
+      BuilderType extends Builder<MessageType, BuilderType>>
       implements MessageLite.Builder {
     // The compiler produces an error if this is not declared explicitly.
     @Override
     public abstract BuilderType clone();
 
-    public BuilderType mergeFrom(final CodedInputStream input)
-                                 throws IOException {
+    @Override
+    public BuilderType mergeFrom(final CodedInputStream input) throws IOException {
       return mergeFrom(input, ExtensionRegistryLite.getEmptyRegistry());
     }
 
     // Re-defined here for return type covariance.
+    @Override
     public abstract BuilderType mergeFrom(
-        final CodedInputStream input,
-        final ExtensionRegistryLite extensionRegistry)
+        final CodedInputStream input, final ExtensionRegistryLite extensionRegistry)
         throws IOException;
 
-    public BuilderType mergeFrom(final ByteString data)
-        throws InvalidProtocolBufferException {
+    @Override
+    public BuilderType mergeFrom(final ByteString data) throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input = data.newCodedInput();
         mergeFrom(input);
@@ -153,9 +162,9 @@ public abstract class AbstractMessageLite implements MessageLite {
       }
     }
 
+    @Override
     public BuilderType mergeFrom(
-        final ByteString data,
-        final ExtensionRegistryLite extensionRegistry)
+        final ByteString data, final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input = data.newCodedInput();
@@ -171,14 +180,14 @@ public abstract class AbstractMessageLite implements MessageLite {
       }
     }
 
-    public BuilderType mergeFrom(final byte[] data)
-        throws InvalidProtocolBufferException {
+    @Override
+    public BuilderType mergeFrom(final byte[] data) throws InvalidProtocolBufferException {
       return mergeFrom(data, 0, data.length);
     }
 
-    public BuilderType mergeFrom(final byte[] data, final int off,
-                                 final int len)
-                                 throws InvalidProtocolBufferException {
+    @Override
+    public BuilderType mergeFrom(final byte[] data, final int off, final int len)
+        throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input =
             CodedInputStream.newInstance(data, off, len);
@@ -194,15 +203,17 @@ public abstract class AbstractMessageLite implements MessageLite {
       }
     }
 
-    public BuilderType mergeFrom(
-        final byte[] data,
-        final ExtensionRegistryLite extensionRegistry)
+    @Override
+    public BuilderType mergeFrom(final byte[] data, final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       return mergeFrom(data, 0, data.length, extensionRegistry);
     }
 
+    @Override
     public BuilderType mergeFrom(
-        final byte[] data, final int off, final int len,
+        final byte[] data,
+        final int off,
+        final int len,
         final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       try {
@@ -220,6 +231,7 @@ public abstract class AbstractMessageLite implements MessageLite {
       }
     }
 
+    @Override
     public BuilderType mergeFrom(final InputStream input) throws IOException {
       final CodedInputStream codedInput = CodedInputStream.newInstance(input);
       mergeFrom(codedInput);
@@ -227,10 +239,9 @@ public abstract class AbstractMessageLite implements MessageLite {
       return (BuilderType) this;
     }
 
+    @Override
     public BuilderType mergeFrom(
-        final InputStream input,
-        final ExtensionRegistryLite extensionRegistry)
-        throws IOException {
+        final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
       final CodedInputStream codedInput = CodedInputStream.newInstance(input);
       mergeFrom(codedInput, extensionRegistry);
       codedInput.checkLastTagWas(0);
@@ -292,10 +303,9 @@ public abstract class AbstractMessageLite implements MessageLite {
       }
     }
 
+    @Override
     public boolean mergeDelimitedFrom(
-        final InputStream input,
-        final ExtensionRegistryLite extensionRegistry)
-        throws IOException {
+        final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
       final int firstByte = input.read();
       if (firstByte == -1) {
         return false;
@@ -306,11 +316,24 @@ public abstract class AbstractMessageLite implements MessageLite {
       return true;
     }
 
-    public boolean mergeDelimitedFrom(final InputStream input)
-        throws IOException {
+    @Override
+    public boolean mergeDelimitedFrom(final InputStream input) throws IOException {
       return mergeDelimitedFrom(input,
           ExtensionRegistryLite.getEmptyRegistry());
     }
+    
+    @Override
+    @SuppressWarnings("unchecked") // isInstance takes care of this
+    public BuilderType mergeFrom(final MessageLite other) {
+      if (!getDefaultInstanceForType().getClass().isInstance(other)) {
+        throw new IllegalArgumentException(
+            "mergeFrom(MessageLite) can only merge messages of the same type.");
+      }
+        
+      return internalMergeFrom((MessageType) other);
+    }
+    
+    protected abstract BuilderType internalMergeFrom(MessageType message);
 
     /**
      * Construct an UninitializedMessageException reporting missing fields in
diff --git a/java/core/src/main/java/com/google/protobuf/AbstractParser.java b/java/core/src/main/java/com/google/protobuf/AbstractParser.java
index 1a4c6311..66b0ee3b 100644
--- a/java/core/src/main/java/com/google/protobuf/AbstractParser.java
+++ b/java/core/src/main/java/com/google/protobuf/AbstractParser.java
@@ -78,26 +78,27 @@ public abstract class AbstractParser<MessageType extends MessageLite>
   private static final ExtensionRegistryLite EMPTY_REGISTRY
       = ExtensionRegistryLite.getEmptyRegistry();
 
+  @Override
   public MessageType parsePartialFrom(CodedInputStream input)
       throws InvalidProtocolBufferException {
     return parsePartialFrom(input, EMPTY_REGISTRY);
   }
 
-  public MessageType parseFrom(CodedInputStream input,
-                               ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return checkMessageInitialized(
         parsePartialFrom(input, extensionRegistry));
   }
 
-  public MessageType parseFrom(CodedInputStream input)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parseFrom(CodedInputStream input) throws InvalidProtocolBufferException {
     return parseFrom(input, EMPTY_REGISTRY);
   }
 
-  public MessageType parsePartialFrom(ByteString data,
-                                      ExtensionRegistryLite extensionRegistry)
-    throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parsePartialFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
     MessageType message;
     try {
       CodedInputStream input = data.newCodedInput();
@@ -113,24 +114,25 @@ public abstract class AbstractParser<MessageType extends MessageLite>
     }
   }
 
-  public MessageType parsePartialFrom(ByteString data)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parsePartialFrom(ByteString data) throws InvalidProtocolBufferException {
     return parsePartialFrom(data, EMPTY_REGISTRY);
   }
 
-  public MessageType parseFrom(ByteString data,
-                               ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return checkMessageInitialized(parsePartialFrom(data, extensionRegistry));
   }
 
-  public MessageType parseFrom(ByteString data)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parseFrom(ByteString data) throws InvalidProtocolBufferException {
     return parseFrom(data, EMPTY_REGISTRY);
   }
 
-  public MessageType parsePartialFrom(byte[] data, int off, int len,
-                                      ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parsePartialFrom(
+      byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     try {
       CodedInputStream input = CodedInputStream.newInstance(data, off, len);
@@ -146,47 +148,50 @@ public abstract class AbstractParser<MessageType extends MessageLite>
     }
   }
 
+  @Override
   public MessageType parsePartialFrom(byte[] data, int off, int len)
       throws InvalidProtocolBufferException {
     return parsePartialFrom(data, off, len, EMPTY_REGISTRY);
   }
 
-  public MessageType parsePartialFrom(byte[] data,
-                                      ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parsePartialFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return parsePartialFrom(data, 0, data.length, extensionRegistry);
   }
 
-  public MessageType parsePartialFrom(byte[] data)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parsePartialFrom(byte[] data) throws InvalidProtocolBufferException {
     return parsePartialFrom(data, 0, data.length, EMPTY_REGISTRY);
   }
 
-  public MessageType parseFrom(byte[] data, int off, int len,
-                               ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseFrom(
+      byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return checkMessageInitialized(
         parsePartialFrom(data, off, len, extensionRegistry));
   }
 
+  @Override
   public MessageType parseFrom(byte[] data, int off, int len)
       throws InvalidProtocolBufferException {
     return parseFrom(data, off, len, EMPTY_REGISTRY);
   }
 
-  public MessageType parseFrom(byte[] data,
-                               ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return parseFrom(data, 0, data.length, extensionRegistry);
   }
 
-  public MessageType parseFrom(byte[] data)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parseFrom(byte[] data) throws InvalidProtocolBufferException {
     return parseFrom(data, EMPTY_REGISTRY);
   }
 
-  public MessageType parsePartialFrom(InputStream input,
-                                      ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parsePartialFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     CodedInputStream codedInput = CodedInputStream.newInstance(input);
     MessageType message = parsePartialFrom(codedInput, extensionRegistry);
@@ -198,26 +203,26 @@ public abstract class AbstractParser<MessageType extends MessageLite>
     return message;
   }
 
-  public MessageType parsePartialFrom(InputStream input)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parsePartialFrom(InputStream input) throws InvalidProtocolBufferException {
     return parsePartialFrom(input, EMPTY_REGISTRY);
   }
 
-  public MessageType parseFrom(InputStream input,
-                               ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return checkMessageInitialized(
         parsePartialFrom(input, extensionRegistry));
   }
 
-  public MessageType parseFrom(InputStream input)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parseFrom(InputStream input) throws InvalidProtocolBufferException {
     return parseFrom(input, EMPTY_REGISTRY);
   }
 
+  @Override
   public MessageType parsePartialDelimitedFrom(
-      InputStream input,
-      ExtensionRegistryLite extensionRegistry)
+      InputStream input, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     int size;
     try {
@@ -233,21 +238,21 @@ public abstract class AbstractParser<MessageType extends MessageLite>
     return parsePartialFrom(limitedInput, extensionRegistry);
   }
 
+  @Override
   public MessageType parsePartialDelimitedFrom(InputStream input)
       throws InvalidProtocolBufferException {
     return parsePartialDelimitedFrom(input, EMPTY_REGISTRY);
   }
 
-  public MessageType parseDelimitedFrom(
-      InputStream input,
-      ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return checkMessageInitialized(
         parsePartialDelimitedFrom(input, extensionRegistry));
   }
 
-  public MessageType parseDelimitedFrom(InputStream input)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parseDelimitedFrom(InputStream input) throws InvalidProtocolBufferException {
     return parseDelimitedFrom(input, EMPTY_REGISTRY);
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/AbstractProtobufList.java b/java/core/src/main/java/com/google/protobuf/AbstractProtobufList.java
index bb6446b2..b17db6e0 100644
--- a/java/core/src/main/java/com/google/protobuf/AbstractProtobufList.java
+++ b/java/core/src/main/java/com/google/protobuf/AbstractProtobufList.java
@@ -34,19 +34,25 @@ import com.google.protobuf.Internal.ProtobufList;
 
 import java.util.AbstractList;
 import java.util.Collection;
+import java.util.List;
+import java.util.RandomAccess;
 
 /**
  * An abstract implementation of {@link ProtobufList} which manages mutability semantics. All mutate
- * methods are check if the list is mutable before proceeding. Subclasses must invoke
+ * methods must check if the list is mutable before proceeding. Subclasses must invoke
  * {@link #ensureIsMutable()} manually when overriding those methods.
+ * <p>
+ * This implementation assumes all subclasses are array based, supporting random access.
  */
 abstract class AbstractProtobufList<E> extends AbstractList<E> implements ProtobufList<E> {
 
+  protected static final int DEFAULT_CAPACITY = 10;
+
   /**
    * Whether or not this list is modifiable.
    */
   private boolean isMutable;
-  
+
   /**
    * Constructs a mutable list by default.
    */
@@ -55,6 +61,44 @@ abstract class AbstractProtobufList<E> extends AbstractList<E> implements Protob
   }
 
   @Override
+  public boolean equals(Object o) {
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof List)) {
+      return false;
+    }
+    // Handle lists that do not support RandomAccess as efficiently as possible by using an iterator
+    // based approach in our super class. Otherwise our index based approach will avoid those
+    // allocations.
+    if (!(o instanceof RandomAccess)) {
+      return super.equals(o);
+    }
+
+    List<?> other = (List<?>) o;
+    final int size = size();
+    if (size != other.size()) {
+      return false;
+    }
+    for (int i = 0; i < size; i++) {
+      if (!get(i).equals(other.get(i))) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    final int size = size();
+    int hashCode = 1;
+    for (int i = 0; i < size; i++) {
+      hashCode = (31 * hashCode) + get(i).hashCode();
+    }
+    return hashCode;
+  }
+
+  @Override
   public boolean add(E e) {
     ensureIsMutable();
     return super.add(e);
diff --git a/java/core/src/main/java/com/google/protobuf/BooleanArrayList.java b/java/core/src/main/java/com/google/protobuf/BooleanArrayList.java
index 70e042f5..8b2820b6 100644
--- a/java/core/src/main/java/com/google/protobuf/BooleanArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/BooleanArrayList.java
@@ -34,7 +34,6 @@ import com.google.protobuf.Internal.BooleanList;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
 import java.util.RandomAccess;
 
 /**
@@ -45,8 +44,6 @@ import java.util.RandomAccess;
 final class BooleanArrayList
     extends AbstractProtobufList<Boolean> implements BooleanList, RandomAccess {
   
-  private static final int DEFAULT_CAPACITY = 10;
-  
   private static final BooleanArrayList EMPTY_LIST = new BooleanArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -60,7 +57,7 @@ final class BooleanArrayList
    * The backing store for the list.
    */
   private boolean[] array;
-  
+
   /**
    * The size of the list distinct from the length of the array. That is, it is the number of
    * elements set in the list.
@@ -71,35 +68,57 @@ final class BooleanArrayList
    * Constructs a new mutable {@code BooleanArrayList} with default capacity.
    */
   BooleanArrayList() {
-    this(DEFAULT_CAPACITY);
+    this(new boolean[DEFAULT_CAPACITY], 0);
   }
 
   /**
-   * Constructs a new mutable {@code BooleanArrayList} with the provided capacity.
+   * Constructs a new mutable {@code BooleanArrayList}.
    */
-  BooleanArrayList(int capacity) {
-    array = new boolean[capacity];
-    size = 0;
+  private BooleanArrayList(boolean[] array, int size) {
+    this.array = array;
+    this.size = size;
   }
-
-  /**
-   * Constructs a new mutable {@code BooleanArrayList} containing the same elements as
-   * {@code other}.
-   */
-  BooleanArrayList(List<Boolean> other) {
-    if (other instanceof BooleanArrayList) {
-      BooleanArrayList list = (BooleanArrayList) other;
-      array = list.array.clone();
-      size = list.size;
-    } else {
-      size = other.size();
-      array = new boolean[size];
-      for (int i = 0; i < size; i++) {
-        array[i] = other.get(i);
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof BooleanArrayList)) {
+      return super.equals(o);
+    }
+    BooleanArrayList other = (BooleanArrayList) o;
+    if (size != other.size) {
+      return false;
+    }
+    
+    final boolean[] arr = other.array;
+    for (int i = 0; i < size; i++) {
+      if (array[i] != arr[i]) {
+        return false;
       }
     }
+    
+    return true;
   }
-  
+
+  @Override
+  public int hashCode() {
+    int result = 1;
+    for (int i = 0; i < size; i++) {
+      result = (31 * result) + Internal.hashBoolean(array[i]);
+    }
+    return result;
+  }
+
+  @Override
+  public BooleanList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size) {
+      throw new IllegalArgumentException();
+    }
+    return new BooleanArrayList(Arrays.copyOf(array, capacity), size);
+  }
+
   @Override
   public Boolean get(int index) {
     return getBoolean(index);
diff --git a/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java b/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
index b92394b8..ad174d0f 100644
--- a/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
+++ b/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
@@ -30,11 +30,18 @@
 
 package com.google.protobuf;
 
+import static java.lang.Math.max;
+
 import com.google.protobuf.Utf8.UnpairedSurrogateException;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.lang.reflect.Field;
+import java.nio.BufferOverflowException;
 import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.security.AccessController;
+import java.security.PrivilegedExceptionAction;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -50,23 +57,21 @@ import java.util.logging.Logger;
  *
  * <p>This class is totally unsynchronized.
  */
-public final class CodedOutputStream {
+public abstract class CodedOutputStream extends ByteOutput {
   private static final Logger logger = Logger.getLogger(CodedOutputStream.class.getName());
+  private static final sun.misc.Unsafe UNSAFE = getUnsafe();
+  private static final boolean HAS_UNSAFE_ARRAY_OPERATIONS = supportsUnsafeArrayOperations();
+  private static final long ARRAY_BASE_OFFSET = byteArrayBaseOffset();
 
-  private static final int LITTLE_ENDIAN_64_SIZE = 8;
+  private static final int FIXED_32_SIZE = 4;
+  private static final int FIXED_64_SIZE = 8;
+  private static final int MAX_VARINT_SIZE = 10;
 
   /**
    * @deprecated Use {@link #computeFixed32SizeNoTag(int)} instead.
    */
-  @Deprecated public static final int LITTLE_ENDIAN_32_SIZE = 4;
-
-  // TODO(dweis): Consider migrating to a ByteBuffer.
-  private final byte[] buffer;
-  private final int limit;
-  private int position;
-  private int totalBytesWritten = 0;
-
-  private final OutputStream output;
+  @Deprecated
+  public static final int LITTLE_ENDIAN_32_SIZE = FIXED_32_SIZE;
 
   /**
    * The buffer size used in {@link #newInstance(OutputStream)}.
@@ -87,34 +92,27 @@ public final class CodedOutputStream {
     return dataLength;
   }
 
-  private CodedOutputStream(final byte[] buffer, final int offset, final int length) {
-    output = null;
-    this.buffer = buffer;
-    position = offset;
-    limit = offset + length;
-  }
-
-  private CodedOutputStream(final OutputStream output, final byte[] buffer) {
-    this.output = output;
-    this.buffer = buffer;
-    position = 0;
-    limit = buffer.length;
-  }
-
   /**
-   * Create a new {@code CodedOutputStream} wrapping the given
-   * {@code OutputStream}.
+   * Create a new {@code CodedOutputStream} wrapping the given {@code OutputStream}.
+   *
+   * <p> NOTE: The provided {@link OutputStream} <strong>MUST NOT</strong> retain access or
+   * modify the provided byte arrays. Doing so may result in corrupted data, which would be
+   * difficult to debug.
    */
   public static CodedOutputStream newInstance(final OutputStream output) {
     return newInstance(output, DEFAULT_BUFFER_SIZE);
   }
 
   /**
-   * Create a new {@code CodedOutputStream} wrapping the given
-   * {@code OutputStream} with a given buffer size.
+   * Create a new {@code CodedOutputStream} wrapping the given {@code OutputStream} with a given
+   * buffer size.
+   *
+   * <p> NOTE: The provided {@link OutputStream} <strong>MUST NOT</strong> retain access or
+   * modify the provided byte arrays. Doing so may result in corrupted data, which would be
+   * difficult to debug.
    */
   public static CodedOutputStream newInstance(final OutputStream output, final int bufferSize) {
-    return new CodedOutputStream(output, new byte[bufferSize]);
+    return new OutputStreamEncoder(output, bufferSize);
   }
 
   /**
@@ -137,160 +135,144 @@ public final class CodedOutputStream {
    */
   public static CodedOutputStream newInstance(
       final byte[] flatArray, final int offset, final int length) {
-    return new CodedOutputStream(flatArray, offset, length);
+    return new ArrayEncoder(flatArray, offset, length);
   }
 
   /**
-   * Create a new {@code CodedOutputStream} that writes to the given ByteBuffer.
+   * Create a new {@code CodedOutputStream} that writes to the given {@link ByteBuffer}.
    */
   public static CodedOutputStream newInstance(ByteBuffer byteBuffer) {
-    return newInstance(byteBuffer, DEFAULT_BUFFER_SIZE);
+    if (byteBuffer.hasArray()) {
+      return new NioHeapEncoder(byteBuffer);
+    }
+    return new NioEncoder(byteBuffer);
   }
 
   /**
-   * Create a new {@code CodedOutputStream} that writes to the given ByteBuffer.
+   * Create a new {@code CodedOutputStream} that writes to the given {@link ByteBuffer}.
+   *
+   * @deprecated the size parameter is no longer used since use of an internal buffer is useless
+   * (and wasteful) when writing to a {@link ByteBuffer}. Use {@link #newInstance(ByteBuffer)}
+   * instead.
    */
-  public static CodedOutputStream newInstance(ByteBuffer byteBuffer, int bufferSize) {
-    return newInstance(new ByteBufferOutputStream(byteBuffer), bufferSize);
+  @Deprecated
+  public static CodedOutputStream newInstance(ByteBuffer byteBuffer,
+      @SuppressWarnings("unused") int unused) {
+    return newInstance(byteBuffer);
   }
 
-  private static class ByteBufferOutputStream extends OutputStream {
-    private final ByteBuffer byteBuffer;
-
-    public ByteBufferOutputStream(ByteBuffer byteBuffer) {
-      this.byteBuffer = byteBuffer;
+  /**
+   * Create a new {@code CodedOutputStream} that writes to the provided {@link ByteOutput}.
+   *
+   * <p> NOTE: The {@link ByteOutput} <strong>MUST NOT</strong> modify the provided buffers. Doing
+   * so may result in corrupted data, which would be difficult to debug.
+   *
+   * @param byteOutput the output target for encoded bytes.
+   * @param bufferSize the size of the internal scratch buffer to be used for string encoding.
+   * Setting this to {@code 0} will disable buffering, requiring an allocation for each encoded
+   * string.
+   */
+  static CodedOutputStream newInstance(ByteOutput byteOutput, int bufferSize) {
+    if (bufferSize < 0) {
+      throw new IllegalArgumentException("bufferSize must be positive");
     }
 
-    @Override
-    public void write(int b) throws IOException {
-      byteBuffer.put((byte) b);
-    }
+    return new ByteOutputEncoder(byteOutput, bufferSize);
+  }
 
-    @Override
-    public void write(byte[] data, int offset, int length) throws IOException {
-      byteBuffer.put(data, offset, length);
-    }
+  // Disallow construction outside of this class.
+  private CodedOutputStream() {
   }
 
   // -----------------------------------------------------------------
 
   /** Encode and write a tag. */
-  public void writeTag(final int fieldNumber, final int wireType) throws IOException {
-    writeRawVarint32(WireFormat.makeTag(fieldNumber, wireType));
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeTag(int fieldNumber, int wireType) throws IOException;
 
   /** Write an {@code int32} field, including tag, to the stream. */
-  public void writeInt32(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeInt32NoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeInt32(int fieldNumber, int value) throws IOException;
 
   /** Write a {@code uint32} field, including tag, to the stream. */
-  public void writeUInt32(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeUInt32NoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeUInt32(int fieldNumber, int value) throws IOException;
 
   /** Write a {@code sint32} field, including tag, to the stream. */
-  public void writeSInt32(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeSInt32NoTag(value);
+  public final void writeSInt32(final int fieldNumber, final int value) throws IOException {
+    writeUInt32(fieldNumber, encodeZigZag32(value));
   }
 
   /** Write a {@code fixed32} field, including tag, to the stream. */
-  public void writeFixed32(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
-    writeFixed32NoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeFixed32(int fieldNumber, int value) throws IOException;
 
   /** Write an {@code sfixed32} field, including tag, to the stream. */
-  public void writeSFixed32(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
-    writeSFixed32NoTag(value);
+  public final void writeSFixed32(final int fieldNumber, final int value) throws IOException {
+    writeFixed32(fieldNumber, value);
   }
 
   /** Write an {@code int64} field, including tag, to the stream. */
-  public void writeInt64(final int fieldNumber, final long value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeInt64NoTag(value);
+  public final void writeInt64(final int fieldNumber, final long value) throws IOException {
+    writeUInt64(fieldNumber, value);
   }
 
   /** Write a {@code uint64} field, including tag, to the stream. */
-  public void writeUInt64(final int fieldNumber, final long value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeUInt64NoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeUInt64(int fieldNumber, long value) throws IOException;
 
   /** Write an {@code sint64} field, including tag, to the stream. */
-  public void writeSInt64(final int fieldNumber, final long value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeSInt64NoTag(value);
+  public final void writeSInt64(final int fieldNumber, final long value) throws IOException {
+    writeUInt64(fieldNumber, encodeZigZag64(value));
   }
 
   /** Write a {@code fixed64} field, including tag, to the stream. */
-  public void writeFixed64(final int fieldNumber, final long value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
-    writeFixed64NoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeFixed64(int fieldNumber, long value) throws IOException;
 
   /** Write an {@code sfixed64} field, including tag, to the stream. */
-  public void writeSFixed64(final int fieldNumber, final long value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
-    writeSFixed64NoTag(value);
+  public final void writeSFixed64(final int fieldNumber, final long value) throws IOException {
+    writeFixed64(fieldNumber, value);
   }
 
   /** Write a {@code float} field, including tag, to the stream. */
-  public void writeFloat(final int fieldNumber, final float value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
-    writeFloatNoTag(value);
+  public final void writeFloat(final int fieldNumber, final float value) throws IOException {
+    writeFixed32(fieldNumber, Float.floatToRawIntBits(value));
   }
 
   /** Write a {@code double} field, including tag, to the stream. */
-  public void writeDouble(final int fieldNumber, final double value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
-    writeDoubleNoTag(value);
+  public final void writeDouble(final int fieldNumber, final double value) throws IOException {
+    writeFixed64(fieldNumber, Double.doubleToRawLongBits(value));
   }
 
   /** Write a {@code bool} field, including tag, to the stream. */
-  public void writeBool(final int fieldNumber, final boolean value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeBoolNoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeBool(int fieldNumber, boolean value) throws IOException;
 
   /**
    * Write an enum field, including tag, to the stream. The provided value is the numeric
    * value used to represent the enum value on the wire (not the enum ordinal value).
    */
-  public void writeEnum(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeEnumNoTag(value);
+  public final void writeEnum(final int fieldNumber, final int value) throws IOException {
+    writeInt32(fieldNumber, value);
   }
 
   /** Write a {@code string} field, including tag, to the stream. */
-  public void writeString(final int fieldNumber, final String value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeStringNoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeString(int fieldNumber, String value) throws IOException;
 
   /** Write a {@code bytes} field, including tag, to the stream. */
-  public void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeBytesNoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeBytes(int fieldNumber, ByteString value) throws IOException;
 
   /** Write a {@code bytes} field, including tag, to the stream. */
-  public void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeByteArrayNoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeByteArray(int fieldNumber, byte[] value) throws IOException;
 
   /** Write a {@code bytes} field, including tag, to the stream. */
-  public void writeByteArray(
-      final int fieldNumber, final byte[] value, final int offset, final int length)
-      throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeByteArrayNoTag(value, offset, length);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeByteArray(int fieldNumber, byte[] value, int offset, int length)
+      throws IOException;
 
   /**
    * Write a {@code bytes} field, including tag, to the stream.
@@ -302,67 +284,36 @@ public final class CodedOutputStream {
    * of a ByteBuffer, you can call
    * {@code writeByteBuffer(fieldNumber, byteBuffer.slice())}.
    */
-  public void writeByteBuffer(final int fieldNumber, final ByteBuffer value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeByteBufferNoTag(value);
-  }
-
-  /** Write a single byte. */
-  public void writeRawByte(final byte value) throws IOException {
-    if (position == limit) {
-      refreshBuffer();
-    }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeByteBuffer(int fieldNumber, ByteBuffer value) throws IOException;
 
-    buffer[position++] = value;
-    ++totalBytesWritten;
+  /**
+   * Write a single byte.
+   */
+  public final void writeRawByte(final byte value) throws IOException {
+    write(value);
   }
 
   /** Write a single byte, represented by an integer value. */
-  public void writeRawByte(final int value) throws IOException {
-    writeRawByte((byte) value);
+  public final void writeRawByte(final int value) throws IOException {
+    write((byte) value);
   }
 
   /** Write an array of bytes. */
-  public void writeRawBytes(final byte[] value) throws IOException {
-    writeRawBytes(value, 0, value.length);
+  public final void writeRawBytes(final byte[] value) throws IOException {
+    write(value, 0, value.length);
   }
 
-  /** Write part of an array of bytes. */
-  public void writeRawBytes(final byte[] value, int offset, int length) throws IOException {
-    if (limit - position >= length) {
-      // We have room in the current buffer.
-      System.arraycopy(value, offset, buffer, position, length);
-      position += length;
-      totalBytesWritten += length;
-    } else {
-      // Write extends past current buffer.  Fill the rest of this buffer and
-      // flush.
-      final int bytesWritten = limit - position;
-      System.arraycopy(value, offset, buffer, position, bytesWritten);
-      offset += bytesWritten;
-      length -= bytesWritten;
-      position = limit;
-      totalBytesWritten += bytesWritten;
-      refreshBuffer();
-
-      // Now deal with the rest.
-      // Since we have an output stream, this is our buffer
-      // and buffer offset == 0
-      if (length <= limit) {
-        // Fits in new buffer.
-        System.arraycopy(value, offset, buffer, 0, length);
-        position = length;
-      } else {
-        // Write is very big.  Let's do it all at once.
-        output.write(value, offset, length);
-      }
-      totalBytesWritten += length;
-    }
+  /**
+   * Write part of an array of bytes.
+   */
+  public final void writeRawBytes(final byte[] value, int offset, int length) throws IOException {
+    write(value, offset, length);
   }
 
   /** Write a byte string. */
-  public void writeRawBytes(final ByteString value) throws IOException {
-    writeRawBytes(value, 0, value.size());
+  public final void writeRawBytes(final ByteString value) throws IOException {
+    value.writeTo(this);
   }
 
   /**
@@ -374,155 +325,138 @@ public final class CodedOutputStream {
    * write the remaining bytes of a ByteBuffer, you can call
    * {@code writeRawBytes(byteBuffer.slice())}.
    */
-  public void writeRawBytes(final ByteBuffer value) throws IOException {
-    if (value.hasArray()) {
-      writeRawBytes(value.array(), value.arrayOffset(), value.capacity());
-    } else {
-      ByteBuffer duplicated = value.duplicate();
-      duplicated.clear();
-      writeRawBytesInternal(duplicated);
-    }
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeRawBytes(final ByteBuffer value) throws IOException;
 
   /** Write an embedded message field, including tag, to the stream. */
-  public void writeMessage(final int fieldNumber, final MessageLite value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeMessageNoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeMessage(final int fieldNumber, final MessageLite value)
+      throws IOException;
 
   /**
    * Write a MessageSet extension field to the stream.  For historical reasons,
    * the wire format differs from normal fields.
    */
-  public void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
-      throws IOException {
-    writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
-    writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
-    writeMessage(WireFormat.MESSAGE_SET_MESSAGE, value);
-    writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
+      throws IOException;
 
   /**
    * Write an unparsed MessageSet extension field to the stream.  For
    * historical reasons, the wire format differs from normal fields.
    */
-  public void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
-      throws IOException {
-    writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
-    writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
-    writeBytes(WireFormat.MESSAGE_SET_MESSAGE, value);
-    writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
+      throws IOException;
 
   // -----------------------------------------------------------------
 
   /** Write an {@code int32} field to the stream. */
-  public void writeInt32NoTag(final int value) throws IOException {
-    if (value >= 0) {
-      writeRawVarint32(value);
-    } else {
-      // Must sign-extend.
-      writeRawVarint64(value);
-    }
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeInt32NoTag(final int value) throws IOException;
 
   /** Write a {@code uint32} field to the stream. */
-  public void writeUInt32NoTag(final int value) throws IOException {
-    writeRawVarint32(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeUInt32NoTag(int value) throws IOException;
 
   /** Write a {@code sint32} field to the stream. */
-  public void writeSInt32NoTag(final int value) throws IOException {
-    writeRawVarint32(encodeZigZag32(value));
+  public final void writeSInt32NoTag(final int value) throws IOException {
+    writeUInt32NoTag(encodeZigZag32(value));
   }
 
   /** Write a {@code fixed32} field to the stream. */
-  public void writeFixed32NoTag(final int value) throws IOException {
-    writeRawLittleEndian32(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeFixed32NoTag(int value) throws IOException;
 
   /** Write a {@code sfixed32} field to the stream. */
-  public void writeSFixed32NoTag(final int value) throws IOException {
-    writeRawLittleEndian32(value);
+  public final void writeSFixed32NoTag(final int value) throws IOException {
+    writeFixed32NoTag(value);
   }
 
   /** Write an {@code int64} field to the stream. */
-  public void writeInt64NoTag(final long value) throws IOException {
-    writeRawVarint64(value);
+  public final void writeInt64NoTag(final long value) throws IOException {
+    writeUInt64NoTag(value);
   }
 
   /** Write a {@code uint64} field to the stream. */
-  public void writeUInt64NoTag(final long value) throws IOException {
-    writeRawVarint64(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeUInt64NoTag(long value) throws IOException;
 
   /** Write a {@code sint64} field to the stream. */
-  public void writeSInt64NoTag(final long value) throws IOException {
-    writeRawVarint64(encodeZigZag64(value));
+  public final void writeSInt64NoTag(final long value) throws IOException {
+    writeUInt64NoTag(encodeZigZag64(value));
   }
 
   /** Write a {@code fixed64} field to the stream. */
-  public void writeFixed64NoTag(final long value) throws IOException {
-    writeRawLittleEndian64(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeFixed64NoTag(long value) throws IOException;
 
   /** Write a {@code sfixed64} field to the stream. */
-  public void writeSFixed64NoTag(final long value) throws IOException {
-    writeRawLittleEndian64(value);
+  public final void writeSFixed64NoTag(final long value) throws IOException {
+    writeFixed64NoTag(value);
   }
 
   /** Write a {@code float} field to the stream. */
-  public void writeFloatNoTag(final float value) throws IOException {
-    writeRawLittleEndian32(Float.floatToRawIntBits(value));
+  public final void writeFloatNoTag(final float value) throws IOException {
+    writeFixed32NoTag(Float.floatToRawIntBits(value));
   }
 
   /** Write a {@code double} field to the stream. */
-  public void writeDoubleNoTag(final double value) throws IOException {
-    writeRawLittleEndian64(Double.doubleToRawLongBits(value));
+  public final void writeDoubleNoTag(final double value) throws IOException {
+    writeFixed64NoTag(Double.doubleToRawLongBits(value));
   }
 
   /** Write a {@code bool} field to the stream. */
-  public void writeBoolNoTag(final boolean value) throws IOException {
-    writeRawByte(value ? 1 : 0);
+  public final void writeBoolNoTag(final boolean value) throws IOException {
+    write((byte) (value ? 1 : 0));
   }
 
   /**
    * Write an enum field to the stream. The provided value is the numeric
    * value used to represent the enum value on the wire (not the enum ordinal value).
    */
-  public void writeEnumNoTag(final int value) throws IOException {
+  public final void writeEnumNoTag(final int value) throws IOException {
     writeInt32NoTag(value);
   }
 
   /** Write a {@code string} field to the stream. */
   // TODO(dweis): Document behavior on ill-formed UTF-16 input.
-  public void writeStringNoTag(final String value) throws IOException {
-    try {
-      efficientWriteStringNoTag(value);
-    } catch (UnpairedSurrogateException e) {
-      logger.log(Level.WARNING,
-          "Converting ill-formed UTF-16. Your Protocol Buffer will not round trip correctly!", e);
-      inefficientWriteStringNoTag(value);
-    }
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeStringNoTag(String value) throws IOException;
 
   /** Write a {@code bytes} field to the stream. */
-  public void writeBytesNoTag(final ByteString value) throws IOException {
-    writeRawVarint32(value.size());
-    writeRawBytes(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeBytesNoTag(final ByteString value) throws IOException;
 
   /** Write a {@code bytes} field to the stream. */
-  public void writeByteArrayNoTag(final byte[] value) throws IOException {
-    writeRawVarint32(value.length);
-    writeRawBytes(value);
+  public final void writeByteArrayNoTag(final byte[] value) throws IOException {
+    writeByteArrayNoTag(value, 0, value.length);
   }
 
   /** Write an embedded message field to the stream. */
-  public void writeMessageNoTag(final MessageLite value) throws IOException {
-    writeRawVarint32(value.getSerializedSize());
-    value.writeTo(this);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeMessageNoTag(final MessageLite value) throws IOException;
+
+  //=================================================================
+
+  @ExperimentalApi
+  @Override
+  public abstract void write(byte value) throws IOException;
+
+  @ExperimentalApi
+  @Override
+  public abstract void write(byte[] value, int offset, int length) throws IOException;
+
+  @ExperimentalApi
+  @Override
+  public abstract void writeLazy(byte[] value, int offset, int length) throws IOException;
+
+  @Override
+  public abstract void write(ByteBuffer value) throws IOException;
+
+  @ExperimentalApi
+  @Override
+  public abstract void writeLazy(ByteBuffer value) throws IOException;
 
   // =================================================================
   // =================================================================
@@ -727,7 +661,7 @@ public final class CodedOutputStream {
 
   /** Compute the number of bytes that would be needed to encode a tag. */
   public static int computeTagSize(final int fieldNumber) {
-    return computeRawVarint32Size(WireFormat.makeTag(fieldNumber, 0));
+    return computeUInt32SizeNoTag(WireFormat.makeTag(fieldNumber, 0));
   }
 
   /**
@@ -736,10 +670,10 @@ public final class CodedOutputStream {
    */
   public static int computeInt32SizeNoTag(final int value) {
     if (value >= 0) {
-      return computeRawVarint32Size(value);
+      return computeUInt32SizeNoTag(value);
     } else {
       // Must sign-extend.
-      return 10;
+      return MAX_VARINT_SIZE;
     }
   }
 
@@ -748,7 +682,19 @@ public final class CodedOutputStream {
    * {@code uint32} field.
    */
   public static int computeUInt32SizeNoTag(final int value) {
-    return computeRawVarint32Size(value);
+    if ((value & (~0 <<  7)) == 0) {
+      return 1;
+    }
+    if ((value & (~0 << 14)) == 0) {
+      return 2;
+    }
+    if ((value & (~0 << 21)) == 0) {
+      return 3;
+    }
+    if ((value & (~0 << 28)) == 0) {
+      return 4;
+    }
+    return 5;
   }
 
   /**
@@ -756,7 +702,7 @@ public final class CodedOutputStream {
    * {@code sint32} field.
    */
   public static int computeSInt32SizeNoTag(final int value) {
-    return computeRawVarint32Size(encodeZigZag32(value));
+    return computeUInt32SizeNoTag(encodeZigZag32(value));
   }
 
   /**
@@ -764,7 +710,7 @@ public final class CodedOutputStream {
    * {@code fixed32} field.
    */
   public static int computeFixed32SizeNoTag(@SuppressWarnings("unused") final int unused) {
-    return LITTLE_ENDIAN_32_SIZE;
+    return FIXED_32_SIZE;
   }
 
   /**
@@ -772,7 +718,7 @@ public final class CodedOutputStream {
    * {@code sfixed32} field.
    */
   public static int computeSFixed32SizeNoTag(@SuppressWarnings("unused") final int unused) {
-    return LITTLE_ENDIAN_32_SIZE;
+    return FIXED_32_SIZE;
   }
 
   /**
@@ -780,15 +726,33 @@ public final class CodedOutputStream {
    * {@code int64} field, including tag.
    */
   public static int computeInt64SizeNoTag(final long value) {
-    return computeRawVarint64Size(value);
+    return computeUInt64SizeNoTag(value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
    * {@code uint64} field, including tag.
    */
-  public static int computeUInt64SizeNoTag(final long value) {
-    return computeRawVarint64Size(value);
+  public static int computeUInt64SizeNoTag(long value) {
+    // handle two popular special cases up front ...
+    if ((value & (~0L << 7)) == 0L) {
+      return 1;
+    }
+    if (value < 0L) {
+      return 10;
+    }
+    // ... leaving us with 8 remaining, which we can divide and conquer
+    int n = 2;
+    if ((value & (~0L << 35)) != 0L) {
+      n += 4; value >>>= 28;
+    }
+    if ((value & (~0L << 21)) != 0L) {
+      n += 2; value >>>= 14;
+    }
+    if ((value & (~0L << 14)) != 0L) {
+      n += 1;
+    }
+    return n;
   }
 
   /**
@@ -796,7 +760,7 @@ public final class CodedOutputStream {
    * {@code sint64} field.
    */
   public static int computeSInt64SizeNoTag(final long value) {
-    return computeRawVarint64Size(encodeZigZag64(value));
+    return computeUInt64SizeNoTag(encodeZigZag64(value));
   }
 
   /**
@@ -804,7 +768,7 @@ public final class CodedOutputStream {
    * {@code fixed64} field.
    */
   public static int computeFixed64SizeNoTag(@SuppressWarnings("unused") final long unused) {
-    return LITTLE_ENDIAN_64_SIZE;
+    return FIXED_64_SIZE;
   }
 
   /**
@@ -812,7 +776,7 @@ public final class CodedOutputStream {
    * {@code sfixed64} field.
    */
   public static int computeSFixed64SizeNoTag(@SuppressWarnings("unused") final long unused) {
-    return LITTLE_ENDIAN_64_SIZE;
+    return FIXED_64_SIZE;
   }
 
   /**
@@ -820,7 +784,7 @@ public final class CodedOutputStream {
    * {@code float} field, including tag.
    */
   public static int computeFloatSizeNoTag(@SuppressWarnings("unused") final float unused) {
-    return LITTLE_ENDIAN_32_SIZE;
+    return FIXED_32_SIZE;
   }
 
   /**
@@ -828,7 +792,7 @@ public final class CodedOutputStream {
    * {@code double} field, including tag.
    */
   public static int computeDoubleSizeNoTag(@SuppressWarnings("unused") final double unused) {
-    return LITTLE_ENDIAN_64_SIZE;
+    return FIXED_64_SIZE;
   }
 
   /**
@@ -862,7 +826,7 @@ public final class CodedOutputStream {
       length = bytes.length;
     }
 
-    return computeRawVarint32Size(length) + length;
+    return computeLengthDelimitedFieldSize(length);
   }
 
   /**
@@ -870,8 +834,7 @@ public final class CodedOutputStream {
    * message stored in lazy field.
    */
   public static int computeLazyFieldSizeNoTag(final LazyFieldLite value) {
-    final int size = value.getSerializedSize();
-    return computeRawVarint32Size(size) + size;
+    return computeLengthDelimitedFieldSize(value.getSerializedSize());
   }
 
   /**
@@ -879,7 +842,7 @@ public final class CodedOutputStream {
    * {@code bytes} field.
    */
   public static int computeBytesSizeNoTag(final ByteString value) {
-    return computeRawVarint32Size(value.size()) + value.size();
+    return computeLengthDelimitedFieldSize(value.size());
   }
 
   /**
@@ -887,7 +850,7 @@ public final class CodedOutputStream {
    * {@code bytes} field.
    */
   public static int computeByteArraySizeNoTag(final byte[] value) {
-    return computeRawVarint32Size(value.length) + value.length;
+    return computeLengthDelimitedFieldSize(value.length);
   }
 
   /**
@@ -895,7 +858,7 @@ public final class CodedOutputStream {
    * {@code bytes} field.
    */
   public static int computeByteBufferSizeNoTag(final ByteBuffer value) {
-    return computeRawVarint32Size(value.capacity()) + value.capacity();
+    return computeLengthDelimitedFieldSize(value.capacity());
   }
 
   /**
@@ -903,8 +866,11 @@ public final class CodedOutputStream {
    * message field.
    */
   public static int computeMessageSizeNoTag(final MessageLite value) {
-    final int size = value.getSerializedSize();
-    return computeRawVarint32Size(size) + size;
+    return computeLengthDelimitedFieldSize(value.getSerializedSize());
+  }
+
+  private static int computeLengthDelimitedFieldSize(int fieldLength) {
+    return computeUInt32SizeNoTag(fieldLength) + fieldLength;
   }
 
   /**
@@ -943,25 +909,13 @@ public final class CodedOutputStream {
    * Flushes the stream and forces any buffered bytes to be written.  This
    * does not flush the underlying OutputStream.
    */
-  public void flush() throws IOException {
-    if (output != null) {
-      refreshBuffer();
-    }
-  }
+  public abstract void flush() throws IOException;
 
   /**
    * If writing to a flat array, return the space left in the array.
    * Otherwise, throws {@code UnsupportedOperationException}.
    */
-  public int spaceLeft() {
-    if (output == null) {
-      return limit - position;
-    } else {
-      throw new UnsupportedOperationException(
-          "spaceLeft() can only be called on CodedOutputStreams that are "
-              + "writing to a flat array.");
-    }
-  }
+  public abstract int spaceLeft();
 
   /**
    * Verifies that {@link #spaceLeft()} returns zero.  It's common to create
@@ -970,7 +924,7 @@ public final class CodedOutputStream {
    * after writing verifies that the message was actually as big as expected,
    * which can help catch bugs.
    */
-  public void checkNoSpaceLeft() {
+  public final void checkNoSpaceLeft() {
     if (spaceLeft() != 0) {
       throw new IllegalStateException("Did not write as much data as expected.");
     }
@@ -1001,183 +955,31 @@ public final class CodedOutputStream {
    * returned value is not guaranteed to be accurate if exceptions have been
    * found in the middle of writing.
    */
-  public int getTotalBytesWritten() {
-    return totalBytesWritten;
-  }
+  public abstract int getTotalBytesWritten();
 
   // =================================================================
 
-  /**
-   * Internal helper that writes the current buffer to the output. The
-   * buffer position is reset to its initial value when this returns.
-   */
-  private void refreshBuffer() throws IOException {
-    if (output == null) {
-      // We're writing to a single buffer.
-      throw new OutOfSpaceException();
-    }
+  /** Write a {@code bytes} field to the stream. Visible for testing. */
+  abstract void writeByteArrayNoTag(final byte[] value, final int offset, final int length)
+      throws IOException;
 
-    // Since we have an output stream, this is our buffer
-    // and buffer offset == 0
-    output.write(buffer, 0, position);
-    position = 0;
-  }
+  final void inefficientWriteStringNoTag(String value, UnpairedSurrogateException cause)
+      throws IOException {
+    logger.log(Level.WARNING,
+        "Converting ill-formed UTF-16. Your Protocol Buffer will not round trip correctly!", cause);
 
-  /** Write a {@code string} field to the stream. */
-  private void inefficientWriteStringNoTag(final String value) throws IOException {
     // Unfortunately there does not appear to be any way to tell Java to encode
     // UTF-8 directly into our buffer, so we have to let it create its own byte
     // array and then copy.
     // TODO(dweis): Consider using nio Charset methods instead.
     final byte[] bytes = value.getBytes(Internal.UTF_8);
-    writeRawVarint32(bytes.length);
-    writeRawBytes(bytes);
-  }
-
-  /**
-   * Write a {@code string} field to the stream efficiently. If the {@code string} is malformed,
-   * this method rolls back its changes and throws an {@link UnpairedSurrogateException} with the
-   * intent that the caller will catch and retry with {@link #inefficientWriteStringNoTag(String)}.
-   *
-   * @param value the string to write to the stream
-   *
-   * @throws UnpairedSurrogateException when {@code value} is ill-formed UTF-16.
-   */
-  private void efficientWriteStringNoTag(final String value) throws IOException {
-    // UTF-8 byte length of the string is at least its UTF-16 code unit length (value.length()),
-    // and at most 3 times of it. We take advantage of this in both branches below.
-    final int maxLength = value.length() * Utf8.MAX_BYTES_PER_CHAR;
-    final int maxLengthVarIntSize = computeRawVarint32Size(maxLength);
-
-    // If we are streaming and the potential length is too big to fit in our buffer, we take the
-    // slower path. Otherwise, we're good to try the fast path.
-    if (output != null && maxLengthVarIntSize + maxLength > limit - position) {
-      // Allocate a byte[] that we know can fit the string and encode into it. String.getBytes()
-      // does the same internally and then does *another copy* to return a byte[] of exactly the
-      // right size. We can skip that copy and just writeRawBytes up to the actualLength of the
-      // UTF-8 encoded bytes.
-      final byte[] encodedBytes = new byte[maxLength];
-      int actualLength = Utf8.encode(value, encodedBytes, 0, maxLength);
-      writeRawVarint32(actualLength);
-      writeRawBytes(encodedBytes, 0, actualLength);
-    } else {
-      // Optimize for the case where we know this length results in a constant varint length as this
-      // saves a pass for measuring the length of the string.
-      final int minLengthVarIntSize = computeRawVarint32Size(value.length());
-      int oldPosition = position;
-      final int length;
-      try {
-        if (minLengthVarIntSize == maxLengthVarIntSize) {
-          position = oldPosition + minLengthVarIntSize;
-          int newPosition = Utf8.encode(value, buffer, position, limit - position);
-          // Since this class is stateful and tracks the position, we rewind and store the state,
-          // prepend the length, then reset it back to the end of the string.
-          position = oldPosition;
-          length = newPosition - oldPosition - minLengthVarIntSize;
-          writeRawVarint32(length);
-          position = newPosition;
-        } else {
-          length = Utf8.encodedLength(value);
-          writeRawVarint32(length);
-          position = Utf8.encode(value, buffer, position, limit - position);
-        }
-      } catch (UnpairedSurrogateException e) {
-        // Be extra careful and restore the original position for retrying the write with the less
-        // efficient path.
-        position = oldPosition;
-        throw e;
-      } catch (ArrayIndexOutOfBoundsException e) {
-        throw new OutOfSpaceException(e);
-      }
-      totalBytesWritten += length;
-    }
-  }
-
-  /** Write a ByteBuffer that isn't backed by an array. */
-  private void writeRawBytesInternal(final ByteBuffer value) throws IOException {
-    int length = value.remaining();
-    if (limit - position >= length) {
-      // We have room in the current buffer.
-      value.get(buffer, position, length);
-      position += length;
-      totalBytesWritten += length;
-    } else {
-      // Write extends past current buffer.  Fill the rest of this buffer and
-      // flush.
-      final int bytesWritten = limit - position;
-      value.get(buffer, position, bytesWritten);
-      length -= bytesWritten;
-      position = limit;
-      totalBytesWritten += bytesWritten;
-      refreshBuffer();
-
-      // Now deal with the rest.
-      // Since we have an output stream, this is our buffer
-      // and buffer offset == 0
-      while (length > limit) {
-        // Copy data into the buffer before writing it to OutputStream.
-        // TODO(xiaofeng): Introduce ZeroCopyOutputStream to avoid this copy.
-        value.get(buffer, 0, limit);
-        output.write(buffer, 0, limit);
-        length -= limit;
-        totalBytesWritten += limit;
-      }
-      value.get(buffer, 0, length);
-      position = length;
-      totalBytesWritten += length;
-    }
-  }
-
-  /** Write a {@code bytes} field to the stream. Visible for testing. */
-  void writeByteArrayNoTag(final byte[] value, final int offset, final int length)
-      throws IOException {
-    writeRawVarint32(length);
-    writeRawBytes(value, offset, length);
-  }
-
-  /**
-   * Write a {@code bytes} field to the stream.  This method will write all
-   * content of the ByteBuffer regardless of the current position and limit
-   * (i.e., the number of bytes to be written is value.capacity(), not
-   * value.remaining()). Furthermore, this method doesn't alter the state of
-   * the passed-in ByteBuffer. Its position, limit, mark, etc. will remain
-   * unchanged. If you only want to write the remaining bytes of a ByteBuffer,
-   * you can call {@code writeByteBufferNoTag(byteBuffer.slice())}.
-   */
-  private void writeByteBufferNoTag(final ByteBuffer value) throws IOException {
-    writeRawVarint32(value.capacity());
-    writeRawBytes(value);
-  }
-
-  /** Write part of a byte string. */
-  private void writeRawBytes(final ByteString value, int offset, int length) throws IOException {
-    if (limit - position >= length) {
-      // We have room in the current buffer.
-      value.copyTo(buffer, offset, position, length);
-      position += length;
-      totalBytesWritten += length;
-    } else {
-      // Write extends past current buffer.  Fill the rest of this buffer and
-      // flush.
-      final int bytesWritten = limit - position;
-      value.copyTo(buffer, offset, position, bytesWritten);
-      offset += bytesWritten;
-      length -= bytesWritten;
-      position = limit;
-      totalBytesWritten += bytesWritten;
-      refreshBuffer();
-
-      // Now deal with the rest.
-      // Since we have an output stream, this is our buffer
-      // and buffer offset == 0
-      if (length <= limit) {
-        // Fits in new buffer.
-        value.copyTo(buffer, offset, 0, length);
-        position = length;
-      } else {
-        value.writeTo(output, offset, length);
-      }
-      totalBytesWritten += length;
+    try {
+      writeUInt32NoTag(bytes.length);
+      writeLazy(bytes, 0, bytes.length);
+    } catch (IndexOutOfBoundsException e) {
+      throw new OutOfSpaceException(e);
+    } catch (OutOfSpaceException e) {
+      throw e;
     }
   }
 
@@ -1189,7 +991,7 @@ public final class CodedOutputStream {
    * @deprecated groups are deprecated.
    */
   @Deprecated
-  public void writeGroup(final int fieldNumber, final MessageLite value) throws IOException {
+  public final void writeGroup(final int fieldNumber, final MessageLite value) throws IOException {
     writeTag(fieldNumber, WireFormat.WIRETYPE_START_GROUP);
     writeGroupNoTag(value);
     writeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP);
@@ -1201,7 +1003,7 @@ public final class CodedOutputStream {
    * @deprecated groups are deprecated.
    */
   @Deprecated
-  public void writeGroupNoTag(final MessageLite value) throws IOException {
+  public final void writeGroupNoTag(final MessageLite value) throws IOException {
     value.writeTo(this);
   }
 
@@ -1232,16 +1034,8 @@ public final class CodedOutputStream {
    * @deprecated use {@link #writeUInt32NoTag} instead.
    */
   @Deprecated
-  public void writeRawVarint32(int value) throws IOException {
-    while (true) {
-      if ((value & ~0x7F) == 0) {
-        writeRawByte(value);
-        return;
-      } else {
-        writeRawByte((value & 0x7F) | 0x80);
-        value >>>= 7;
-      }
-    }
+  public final void writeRawVarint32(int value) throws IOException {
+    writeUInt32NoTag(value);
   }
 
   /**
@@ -1250,16 +1044,8 @@ public final class CodedOutputStream {
    * @deprecated use {@link #writeUInt64NoTag} instead.
    */
   @Deprecated
-  public void writeRawVarint64(long value) throws IOException {
-    while (true) {
-      if ((value & ~0x7FL) == 0) {
-        writeRawByte((int) value);
-        return;
-      } else {
-        writeRawByte(((int) value & 0x7F) | 0x80);
-        value >>>= 7;
-      }
-    }
+  public final void writeRawVarint64(long value) throws IOException {
+    writeUInt64NoTag(value);
   }
 
   /**
@@ -1271,19 +1057,7 @@ public final class CodedOutputStream {
    */
   @Deprecated
   public static int computeRawVarint32Size(final int value) {
-    if ((value & (~0 << 7)) == 0) {
-      return 1;
-    }
-    if ((value & (~0 << 14)) == 0) {
-      return 2;
-    }
-    if ((value & (~0 << 21)) == 0) {
-      return 3;
-    }
-    if ((value & (~0 << 28)) == 0) {
-      return 4;
-    }
-    return 5;
+    return computeUInt32SizeNoTag(value);
   }
 
   /**
@@ -1293,27 +1067,7 @@ public final class CodedOutputStream {
    */
   @Deprecated
   public static int computeRawVarint64Size(long value) {
-    // handle two popular special cases up front ...
-    if ((value & (~0L << 7)) == 0L) {
-      return 1;
-    }
-    if (value < 0L) {
-      return 10;
-    }
-    // ... leaving us with 8 remaining, which we can divide and conquer
-    int n = 2;
-    if ((value & (~0L << 35)) != 0L) {
-      n += 4;
-      value >>>= 28;
-    }
-    if ((value & (~0L << 21)) != 0L) {
-      n += 2;
-      value >>>= 14;
-    }
-    if ((value & (~0L << 14)) != 0L) {
-      n += 1;
-    }
-    return n;
+    return computeUInt64SizeNoTag(value);
   }
 
   /**
@@ -1322,11 +1076,8 @@ public final class CodedOutputStream {
    * @deprecated Use {@link #writeFixed32NoTag} instead.
    */
   @Deprecated
-  public void writeRawLittleEndian32(final int value) throws IOException {
-    writeRawByte((value) & 0xFF);
-    writeRawByte((value >> 8) & 0xFF);
-    writeRawByte((value >> 16) & 0xFF);
-    writeRawByte((value >> 24) & 0xFF);
+  public final void writeRawLittleEndian32(final int value) throws IOException {
+    writeFixed32NoTag(value);
   }
 
   /**
@@ -1335,14 +1086,1579 @@ public final class CodedOutputStream {
    * @deprecated Use {@link #writeFixed64NoTag} instead.
    */
   @Deprecated
-  public void writeRawLittleEndian64(final long value) throws IOException {
-    writeRawByte((int) (value) & 0xFF);
-    writeRawByte((int) (value >> 8) & 0xFF);
-    writeRawByte((int) (value >> 16) & 0xFF);
-    writeRawByte((int) (value >> 24) & 0xFF);
-    writeRawByte((int) (value >> 32) & 0xFF);
-    writeRawByte((int) (value >> 40) & 0xFF);
-    writeRawByte((int) (value >> 48) & 0xFF);
-    writeRawByte((int) (value >> 56) & 0xFF);
+  public final void writeRawLittleEndian64(final long value) throws IOException {
+    writeFixed64NoTag(value);
+  }
+
+  // =================================================================
+
+  /**
+   * A {@link CodedOutputStream} that writes directly to a byte array.
+   */
+  private static class ArrayEncoder extends CodedOutputStream {
+    private final byte[] buffer;
+    private final int offset;
+    private final int limit;
+    private int position;
+
+    ArrayEncoder(byte[] buffer, int offset, int length) {
+      if (buffer == null) {
+        throw new NullPointerException("buffer");
+      }
+      if ((offset | length | (buffer.length - (offset + length))) < 0) {
+        throw new IllegalArgumentException(String.format(
+            "Array range is invalid. Buffer.length=%d, offset=%d, length=%d",
+            buffer.length, offset, length));
+      }
+      this.buffer = buffer;
+      this.offset = offset;
+      position = offset;
+      limit = offset + length;
+    }
+
+    @Override
+    public final void writeTag(final int fieldNumber, final int wireType) throws IOException {
+      writeUInt32NoTag(WireFormat.makeTag(fieldNumber, wireType));
+    }
+
+    @Override
+    public final void writeInt32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeInt32NoTag(value);
+    }
+
+    @Override
+    public final void writeUInt32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeUInt32NoTag(value);
+    }
+
+    @Override
+    public final void writeFixed32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
+      writeFixed32NoTag(value);
+    }
+
+    @Override
+    public final void writeUInt64(final int fieldNumber, final long value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeUInt64NoTag(value);
+    }
+
+    @Override
+    public final void writeFixed64(final int fieldNumber, final long value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
+      writeFixed64NoTag(value);
+    }
+
+    @Override
+    public final void writeBool(final int fieldNumber, final boolean value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      write((byte) (value ? 1 : 0));
+    }
+
+    @Override
+    public final void writeString(final int fieldNumber, final String value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeStringNoTag(value);
+    }
+
+    @Override
+    public final void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeBytesNoTag(value);
+    }
+
+    @Override
+    public final void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
+      writeByteArray(fieldNumber, value, 0, value.length);
+    }
+
+    @Override
+    public final void writeByteArray(
+        final int fieldNumber, final byte[] value, final int offset, final int length)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeByteArrayNoTag(value, offset, length);
+    }
+
+    @Override
+    public final void writeByteBuffer(final int fieldNumber, final ByteBuffer value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeUInt32NoTag(value.capacity());
+      writeRawBytes(value);
+    }
+
+    @Override
+    public final void writeBytesNoTag(final ByteString value) throws IOException {
+      writeUInt32NoTag(value.size());
+      value.writeTo(this);
+    }
+
+    @Override
+    public final void writeByteArrayNoTag(final byte[] value, int offset, int length)
+        throws IOException {
+      writeUInt32NoTag(length);
+      write(value, offset, length);
+    }
+
+    @Override
+    public final void writeRawBytes(final ByteBuffer value) throws IOException {
+      if (value.hasArray()) {
+        write(value.array(), value.arrayOffset(), value.capacity());
+      } else {
+        ByteBuffer duplicated = value.duplicate();
+        duplicated.clear();
+        write(duplicated);
+      }
+    }
+
+    @Override
+    public final void writeMessage(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeMessageNoTag(value);
+    }
+
+    @Override
+    public final void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeMessage(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public final void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeBytes(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public final void writeMessageNoTag(final MessageLite value) throws IOException {
+      writeUInt32NoTag(value.getSerializedSize());
+      value.writeTo(this);
+    }
+
+    @Override
+    public final void write(byte value) throws IOException {
+      try {
+        buffer[position++] = value;
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(new IndexOutOfBoundsException(
+            String.format("Pos: %d, limit: %d, len: %d", position, limit, 1)));
+      }
+    }
+
+    @Override
+    public final void writeInt32NoTag(int value) throws IOException {
+      if (value >= 0) {
+        writeUInt32NoTag(value);
+      } else {
+        // Must sign-extend.
+        writeUInt64NoTag(value);
+      }
+    }
+
+    @Override
+    public final void writeUInt32NoTag(int value) throws IOException {
+      if (HAS_UNSAFE_ARRAY_OPERATIONS && spaceLeft() >= MAX_VARINT_SIZE) {
+        long pos = ARRAY_BASE_OFFSET + position;
+        while (true) {
+          if ((value & ~0x7F) == 0) {
+            UNSAFE.putByte(buffer, pos++, (byte) value);
+            position++;
+            return;
+          } else {
+            UNSAFE.putByte(buffer, pos++, (byte) ((value & 0x7F) | 0x80));
+            position++;
+            value >>>= 7;
+          }
+        }
+      } else {
+        try {
+          while (true) {
+            if ((value & ~0x7F) == 0) {
+              buffer[position++] = (byte) value;
+              return;
+            } else {
+              buffer[position++] = (byte) ((value & 0x7F) | 0x80);
+              value >>>= 7;
+            }
+          }
+        } catch (IndexOutOfBoundsException e) {
+          throw new OutOfSpaceException(
+              new IndexOutOfBoundsException(
+                  String.format("Pos: %d, limit: %d, len: %d", position, limit, 1)));
+        }
+      }
+    }
+
+    @Override
+    public final void writeFixed32NoTag(int value) throws IOException {
+      try {
+        buffer[position++] = (byte) (value & 0xFF);
+        buffer[position++] = (byte) ((value >> 8) & 0xFF);
+        buffer[position++] = (byte) ((value >> 16) & 0xFF);
+        buffer[position++] = (byte) ((value >> 24) & 0xFF);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(
+            new IndexOutOfBoundsException(
+                String.format("Pos: %d, limit: %d, len: %d", position, limit, 1)));
+      }
+    }
+
+    @Override
+    public final void writeUInt64NoTag(long value) throws IOException {
+      if (HAS_UNSAFE_ARRAY_OPERATIONS && spaceLeft() >= MAX_VARINT_SIZE) {
+        long pos = ARRAY_BASE_OFFSET + position;
+        while (true) {
+          if ((value & ~0x7FL) == 0) {
+            UNSAFE.putByte(buffer, pos++, (byte) value);
+            position++;
+            return;
+          } else {
+            UNSAFE.putByte(buffer, pos++, (byte) (((int) value & 0x7F) | 0x80));
+            position++;
+            value >>>= 7;
+          }
+        }
+      } else {
+        try {
+          while (true) {
+            if ((value & ~0x7FL) == 0) {
+              buffer[position++] = (byte) value;
+              return;
+            } else {
+              buffer[position++] = (byte) (((int) value & 0x7F) | 0x80);
+              value >>>= 7;
+            }
+          }
+        } catch (IndexOutOfBoundsException e) {
+          throw new OutOfSpaceException(
+              new IndexOutOfBoundsException(
+                  String.format("Pos: %d, limit: %d, len: %d", position, limit, 1)));
+        }
+      }
+    }
+
+    @Override
+    public final void writeFixed64NoTag(long value) throws IOException {
+      try {
+        buffer[position++] = (byte) ((int) (value) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 8) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 16) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 24) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 32) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 40) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 48) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 56) & 0xFF);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(
+            new IndexOutOfBoundsException(
+                String.format("Pos: %d, limit: %d, len: %d", position, limit, 1)));
+      }
+    }
+
+    @Override
+    public final void write(byte[] value, int offset, int length) throws IOException {
+      try {
+        System.arraycopy(value, offset, buffer, position, length);
+        position += length;
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(
+            new IndexOutOfBoundsException(
+                String.format("Pos: %d, limit: %d, len: %d", position, limit, length)));
+      }
+    }
+
+    @Override
+    public final void writeLazy(byte[] value, int offset, int length) throws IOException {
+      write(value, offset, length);
+    }
+
+    @Override
+    public final void write(ByteBuffer value) throws IOException {
+      final int length = value.remaining();
+      try {
+        value.get(buffer, position, length);
+        position += length;
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(
+            new IndexOutOfBoundsException(
+                String.format("Pos: %d, limit: %d, len: %d", position, limit, length)));
+      }
+    }
+
+    @Override
+    public final void writeLazy(ByteBuffer value) throws IOException {
+      write(value);
+    }
+
+    @Override
+    public final void writeStringNoTag(String value) throws IOException {
+      final int oldPosition = position;
+      try {
+        // UTF-8 byte length of the string is at least its UTF-16 code unit length (value.length()),
+        // and at most 3 times of it. We take advantage of this in both branches below.
+        final int maxLength = value.length() * Utf8.MAX_BYTES_PER_CHAR;
+        final int maxLengthVarIntSize = computeUInt32SizeNoTag(maxLength);
+        final int minLengthVarIntSize = computeUInt32SizeNoTag(value.length());
+        if (minLengthVarIntSize == maxLengthVarIntSize) {
+          position = oldPosition + minLengthVarIntSize;
+          int newPosition = Utf8.encode(value, buffer, position, spaceLeft());
+          // Since this class is stateful and tracks the position, we rewind and store the state,
+          // prepend the length, then reset it back to the end of the string.
+          position = oldPosition;
+          int length = newPosition - oldPosition - minLengthVarIntSize;
+          writeUInt32NoTag(length);
+          position = newPosition;
+        } else {
+          int length = Utf8.encodedLength(value);
+          writeUInt32NoTag(length);
+          position = Utf8.encode(value, buffer, position, spaceLeft());
+        }
+      } catch (UnpairedSurrogateException e) {
+        // Roll back the change - we fall back to inefficient path.
+        position = oldPosition;
+
+        // TODO(nathanmittler): We should throw an IOException here instead.
+        inefficientWriteStringNoTag(value, e);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void flush() {
+      // Do nothing.
+    }
+
+    @Override
+    public final int spaceLeft() {
+      return limit - position;
+    }
+
+    @Override
+    public final int getTotalBytesWritten() {
+      return position - offset;
+    }
+  }
+
+  /**
+   * A {@link CodedOutputStream} that writes directly to a heap {@link ByteBuffer}. Writes are
+   * done directly to the underlying array. The buffer position is only updated after a flush.
+   */
+  private static final class NioHeapEncoder extends ArrayEncoder {
+    private final ByteBuffer byteBuffer;
+    private int initialPosition;
+
+    NioHeapEncoder(ByteBuffer byteBuffer) {
+      super(byteBuffer.array(), byteBuffer.arrayOffset() + byteBuffer.position(),
+          byteBuffer.remaining());
+      this.byteBuffer = byteBuffer;
+      this.initialPosition = byteBuffer.position();
+    }
+
+    @Override
+    public void flush() {
+      // Update the position on the buffer.
+      byteBuffer.position(initialPosition + getTotalBytesWritten());
+    }
+  }
+
+  /**
+   * A {@link CodedOutputStream} that writes directly to a {@link ByteBuffer}.
+   */
+  private static final class NioEncoder extends CodedOutputStream {
+    private final ByteBuffer originalBuffer;
+    private final ByteBuffer buffer;
+    private final int initialPosition;
+
+    NioEncoder(ByteBuffer buffer) {
+      this.originalBuffer = buffer;
+      this.buffer = buffer.duplicate().order(ByteOrder.LITTLE_ENDIAN);
+      initialPosition = buffer.position();
+    }
+
+    @Override
+    public void writeTag(final int fieldNumber, final int wireType) throws IOException {
+      writeUInt32NoTag(WireFormat.makeTag(fieldNumber, wireType));
+    }
+
+    @Override
+    public void writeInt32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeInt32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeUInt32NoTag(value);
+    }
+
+    @Override
+    public void writeFixed32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
+      writeFixed32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt64(final int fieldNumber, final long value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeUInt64NoTag(value);
+    }
+
+    @Override
+    public void writeFixed64(final int fieldNumber, final long value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
+      writeFixed64NoTag(value);
+    }
+
+    @Override
+    public void writeBool(final int fieldNumber, final boolean value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      write((byte) (value ? 1 : 0));
+    }
+
+    @Override
+    public void writeString(final int fieldNumber, final String value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeStringNoTag(value);
+    }
+
+    @Override
+    public void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeBytesNoTag(value);
+    }
+
+    @Override
+    public void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
+      writeByteArray(fieldNumber, value, 0, value.length);
+    }
+
+    @Override
+    public void writeByteArray(
+        final int fieldNumber, final byte[] value, final int offset, final int length)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeByteArrayNoTag(value, offset, length);
+    }
+
+    @Override
+    public void writeByteBuffer(final int fieldNumber, final ByteBuffer value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeUInt32NoTag(value.capacity());
+      writeRawBytes(value);
+    }
+
+    @Override
+    public void writeMessage(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeMessageNoTag(value);
+    }
+
+    @Override
+    public void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeMessage(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeBytes(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeMessageNoTag(final MessageLite value) throws IOException {
+      writeUInt32NoTag(value.getSerializedSize());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void write(byte value) throws IOException {
+      try {
+        buffer.put(value);
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeBytesNoTag(final ByteString value) throws IOException {
+      writeUInt32NoTag(value.size());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void writeByteArrayNoTag(final byte[] value, int offset, int length) throws IOException {
+      writeUInt32NoTag(length);
+      write(value, offset, length);
+    }
+
+    @Override
+    public void writeRawBytes(final ByteBuffer value) throws IOException {
+      if (value.hasArray()) {
+        write(value.array(), value.arrayOffset(), value.capacity());
+      } else {
+        ByteBuffer duplicated = value.duplicate();
+        duplicated.clear();
+        write(duplicated);
+      }
+    }
+
+    @Override
+    public void writeInt32NoTag(int value) throws IOException {
+      if (value >= 0) {
+        writeUInt32NoTag(value);
+      } else {
+        // Must sign-extend.
+        writeUInt64NoTag(value);
+      }
+    }
+
+    @Override
+    public void writeUInt32NoTag(int value) throws IOException {
+      try {
+        while (true) {
+          if ((value & ~0x7F) == 0) {
+            buffer.put((byte) value);
+            return;
+          } else {
+            buffer.put((byte) ((value & 0x7F) | 0x80));
+            value >>>= 7;
+          }
+        }
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeFixed32NoTag(int value) throws IOException {
+      try {
+        buffer.putInt(value);
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeUInt64NoTag(long value) throws IOException {
+      try {
+        while (true) {
+          if ((value & ~0x7FL) == 0) {
+            buffer.put((byte) value);
+            return;
+          } else {
+            buffer.put((byte) (((int) value & 0x7F) | 0x80));
+            value >>>= 7;
+          }
+        }
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeFixed64NoTag(long value) throws IOException {
+      try {
+        buffer.putLong(value);
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void write(byte[] value, int offset, int length) throws IOException {
+      try {
+        buffer.put(value, offset, length);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(e);
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeLazy(byte[] value, int offset, int length) throws IOException {
+      write(value, offset, length);
+    }
+
+    @Override
+    public void write(ByteBuffer value) throws IOException {
+      try {
+        buffer.put(value);
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeLazy(ByteBuffer value) throws IOException {
+      write(value);
+    }
+
+    @Override
+    public void writeStringNoTag(String value) throws IOException {
+      final int startPos = buffer.position();
+      try {
+        // UTF-8 byte length of the string is at least its UTF-16 code unit length (value.length()),
+        // and at most 3 times of it. We take advantage of this in both branches below.
+        final int maxEncodedSize = value.length() * Utf8.MAX_BYTES_PER_CHAR;
+        final int maxLengthVarIntSize = computeUInt32SizeNoTag(maxEncodedSize);
+        final int minLengthVarIntSize = computeUInt32SizeNoTag(value.length());
+        if (minLengthVarIntSize == maxLengthVarIntSize) {
+          // Save the current position and increment past the length field. We'll come back
+          // and write the length field after the encoding is complete.
+          final int startOfBytes = buffer.position() + minLengthVarIntSize;
+          buffer.position(startOfBytes);
+
+          // Encode the string.
+          encode(value);
+
+          // Now go back to the beginning and write the length.
+          int endOfBytes = buffer.position();
+          buffer.position(startPos);
+          writeUInt32NoTag(endOfBytes - startOfBytes);
+
+          // Reposition the buffer past the written data.
+          buffer.position(endOfBytes);
+        } else {
+          final int length = Utf8.encodedLength(value);
+          writeUInt32NoTag(length);
+          encode(value);
+        }
+      } catch (UnpairedSurrogateException e) {
+        // Roll back the change and convert to an IOException.
+        buffer.position(startPos);
+
+        // TODO(nathanmittler): We should throw an IOException here instead.
+        inefficientWriteStringNoTag(value, e);
+      } catch (IllegalArgumentException e) {
+        // Thrown by buffer.position() if out of range.
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void flush() {
+      // Update the position of the original buffer.
+      originalBuffer.position(buffer.position());
+    }
+
+    @Override
+    public int spaceLeft() {
+      return buffer.remaining();
+    }
+
+    @Override
+    public int getTotalBytesWritten() {
+      return buffer.position() - initialPosition;
+    }
+
+    private void encode(String value) throws IOException {
+      try {
+        Utf8.encodeUtf8(value, buffer);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+  }
+
+  /**
+   * Abstract base class for buffered encoders.
+   */
+  private abstract static class AbstractBufferedEncoder extends CodedOutputStream {
+    final byte[] buffer;
+    final int limit;
+    int position;
+    int totalBytesWritten;
+
+    AbstractBufferedEncoder(int bufferSize) {
+      if (bufferSize < 0) {
+        throw new IllegalArgumentException("bufferSize must be >= 0");
+      }
+      // As an optimization, we require that the buffer be able to store at least 2
+      // varints so that we can buffer any integer write (tag + value). This reduces the
+      // number of range checks for a single write to 1 (i.e. if there is not enough space
+      // to buffer the tag+value, flush and then buffer it).
+      this.buffer = new byte[max(bufferSize, MAX_VARINT_SIZE * 2)];
+      this.limit = buffer.length;
+    }
+
+    @Override
+    public final int spaceLeft() {
+      throw new UnsupportedOperationException(
+          "spaceLeft() can only be called on CodedOutputStreams that are "
+              + "writing to a flat array or ByteBuffer.");
+    }
+
+    @Override
+    public final int getTotalBytesWritten() {
+      return totalBytesWritten;
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void buffer(byte value) {
+      buffer[position++] = value;
+      totalBytesWritten++;
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferTag(final int fieldNumber, final int wireType) {
+      bufferUInt32NoTag(WireFormat.makeTag(fieldNumber, wireType));
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferInt32NoTag(final int value) {
+      if (value >= 0) {
+        bufferUInt32NoTag(value);
+      } else {
+        // Must sign-extend.
+        bufferUInt64NoTag(value);
+      }
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferUInt32NoTag(int value) {
+      if (HAS_UNSAFE_ARRAY_OPERATIONS) {
+        final long originalPos = ARRAY_BASE_OFFSET + position;
+        long pos = originalPos;
+        while (true) {
+          if ((value & ~0x7F) == 0) {
+            UNSAFE.putByte(buffer, pos++, (byte) value);
+            break;
+          } else {
+            UNSAFE.putByte(buffer, pos++, (byte) ((value & 0x7F) | 0x80));
+            value >>>= 7;
+          }
+        }
+        int delta = (int) (pos - originalPos);
+        position += delta;
+        totalBytesWritten += delta;
+      } else {
+        while (true) {
+          if ((value & ~0x7F) == 0) {
+            buffer[position++] = (byte) value;
+            totalBytesWritten++;
+            return;
+          } else {
+            buffer[position++] = (byte) ((value & 0x7F) | 0x80);
+            totalBytesWritten++;
+            value >>>= 7;
+          }
+        }
+      }
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferUInt64NoTag(long value) {
+      if (HAS_UNSAFE_ARRAY_OPERATIONS) {
+        final long originalPos = ARRAY_BASE_OFFSET + position;
+        long pos = originalPos;
+        while (true) {
+          if ((value & ~0x7FL) == 0) {
+            UNSAFE.putByte(buffer, pos++, (byte) value);
+            break;
+          } else {
+            UNSAFE.putByte(buffer, pos++, (byte) (((int) value & 0x7F) | 0x80));
+            value >>>= 7;
+          }
+        }
+        int delta = (int) (pos - originalPos);
+        position += delta;
+        totalBytesWritten += delta;
+      } else {
+        while (true) {
+          if ((value & ~0x7FL) == 0) {
+            buffer[position++] = (byte) value;
+            totalBytesWritten++;
+            return;
+          } else {
+            buffer[position++] = (byte) (((int) value & 0x7F) | 0x80);
+            totalBytesWritten++;
+            value >>>= 7;
+          }
+        }
+      }
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferFixed32NoTag(int value) {
+      buffer[position++] = (byte) (value & 0xFF);
+      buffer[position++] = (byte) ((value >> 8) & 0xFF);
+      buffer[position++] = (byte) ((value >> 16) & 0xFF);
+      buffer[position++] = (byte) ((value >> 24) & 0xFF);
+      totalBytesWritten += FIXED_32_SIZE;
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferFixed64NoTag(long value) {
+      buffer[position++] = (byte) (value & 0xFF);
+      buffer[position++] = (byte) ((value >> 8) & 0xFF);
+      buffer[position++] = (byte) ((value >> 16) & 0xFF);
+      buffer[position++] = (byte) ((value >> 24) & 0xFF);
+      buffer[position++] = (byte) ((int) (value >> 32) & 0xFF);
+      buffer[position++] = (byte) ((int) (value >> 40) & 0xFF);
+      buffer[position++] = (byte) ((int) (value >> 48) & 0xFF);
+      buffer[position++] = (byte) ((int) (value >> 56) & 0xFF);
+      totalBytesWritten += FIXED_64_SIZE;
+    }
+  }
+
+  /**
+   * A {@link CodedOutputStream} that decorates a {@link ByteOutput}. It internal buffer only to
+   * support string encoding operations. All other writes are just passed through to the
+   * {@link ByteOutput}.
+   */
+  private static final class ByteOutputEncoder extends AbstractBufferedEncoder {
+    private final ByteOutput out;
+
+    ByteOutputEncoder(ByteOutput out, int bufferSize) {
+      super(bufferSize);
+      if (out == null) {
+        throw new NullPointerException("out");
+      }
+      this.out = out;
+    }
+
+    @Override
+    public void writeTag(final int fieldNumber, final int wireType) throws IOException {
+      writeUInt32NoTag(WireFormat.makeTag(fieldNumber, wireType));
+    }
+
+    @Override
+    public void writeInt32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferInt32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferUInt32NoTag(value);
+    }
+
+    @Override
+    public void writeFixed32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + FIXED_32_SIZE);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
+      bufferFixed32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt64(final int fieldNumber, final long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferUInt64NoTag(value);
+    }
+
+    @Override
+    public void writeFixed64(final int fieldNumber, final long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + FIXED_64_SIZE);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
+      bufferFixed64NoTag(value);
+    }
+
+    @Override
+    public void writeBool(final int fieldNumber, final boolean value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + 1);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      buffer((byte) (value ? 1 : 0));
+    }
+
+    @Override
+    public void writeString(final int fieldNumber, final String value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeStringNoTag(value);
+    }
+
+    @Override
+    public void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeBytesNoTag(value);
+    }
+
+    @Override
+    public void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
+      writeByteArray(fieldNumber, value, 0, value.length);
+    }
+
+    @Override
+    public void writeByteArray(
+        final int fieldNumber, final byte[] value, final int offset, final int length)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeByteArrayNoTag(value, offset, length);
+    }
+
+    @Override
+    public void writeByteBuffer(final int fieldNumber, final ByteBuffer value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeUInt32NoTag(value.capacity());
+      writeRawBytes(value);
+    }
+
+    @Override
+    public void writeBytesNoTag(final ByteString value) throws IOException {
+      writeUInt32NoTag(value.size());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void writeByteArrayNoTag(final byte[] value, int offset, int length) throws IOException {
+      writeUInt32NoTag(length);
+      write(value, offset, length);
+    }
+
+    @Override
+    public void writeRawBytes(final ByteBuffer value) throws IOException {
+      if (value.hasArray()) {
+        write(value.array(), value.arrayOffset(), value.capacity());
+      } else {
+        ByteBuffer duplicated = value.duplicate();
+        duplicated.clear();
+        write(duplicated);
+      }
+    }
+
+    @Override
+    public void writeMessage(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeMessageNoTag(value);
+    }
+
+    @Override
+    public void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeMessage(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeBytes(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeMessageNoTag(final MessageLite value) throws IOException {
+      writeUInt32NoTag(value.getSerializedSize());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void write(byte value) throws IOException {
+      if (position == limit) {
+        doFlush();
+      }
+
+      buffer(value);
+    }
+
+    @Override
+    public void writeInt32NoTag(int value) throws IOException {
+      if (value >= 0) {
+        writeUInt32NoTag(value);
+      } else {
+        // Must sign-extend.
+        writeUInt64NoTag(value);
+      }
+    }
+
+    @Override
+    public void writeUInt32NoTag(int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE);
+      bufferUInt32NoTag(value);
+    }
+
+    @Override
+    public void writeFixed32NoTag(final int value) throws IOException {
+      flushIfNotAvailable(FIXED_32_SIZE);
+      bufferFixed32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt64NoTag(long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE);
+      bufferUInt64NoTag(value);
+    }
+
+    @Override
+    public void writeFixed64NoTag(final long value) throws IOException {
+      flushIfNotAvailable(FIXED_64_SIZE);
+      bufferFixed64NoTag(value);
+    }
+
+    @Override
+    public void writeStringNoTag(String value) throws IOException {
+      // UTF-8 byte length of the string is at least its UTF-16 code unit length (value.length()),
+      // and at most 3 times of it. We take advantage of this in both branches below.
+      final int maxLength = value.length() * Utf8.MAX_BYTES_PER_CHAR;
+      final int maxLengthVarIntSize = computeUInt32SizeNoTag(maxLength);
+
+      // If we are streaming and the potential length is too big to fit in our buffer, we take the
+      // slower path.
+      if (maxLengthVarIntSize + maxLength > limit) {
+        // Allocate a byte[] that we know can fit the string and encode into it. String.getBytes()
+        // does the same internally and then does *another copy* to return a byte[] of exactly the
+        // right size. We can skip that copy and just writeRawBytes up to the actualLength of the
+        // UTF-8 encoded bytes.
+        final byte[] encodedBytes = new byte[maxLength];
+        int actualLength = Utf8.encode(value, encodedBytes, 0, maxLength);
+        writeUInt32NoTag(actualLength);
+        writeLazy(encodedBytes, 0, actualLength);
+        return;
+      }
+
+      // Fast path: we have enough space available in our buffer for the string...
+      if (maxLengthVarIntSize + maxLength > limit - position) {
+        // Flush to free up space.
+        doFlush();
+      }
+
+      final int oldPosition = position;
+      try {
+        // Optimize for the case where we know this length results in a constant varint length as
+        // this saves a pass for measuring the length of the string.
+        final int minLengthVarIntSize = computeUInt32SizeNoTag(value.length());
+
+        if (minLengthVarIntSize == maxLengthVarIntSize) {
+          position = oldPosition + minLengthVarIntSize;
+          int newPosition = Utf8.encode(value, buffer, position, limit - position);
+          // Since this class is stateful and tracks the position, we rewind and store the state,
+          // prepend the length, then reset it back to the end of the string.
+          position = oldPosition;
+          int length = newPosition - oldPosition - minLengthVarIntSize;
+          bufferUInt32NoTag(length);
+          position = newPosition;
+          totalBytesWritten += length;
+        } else {
+          int length = Utf8.encodedLength(value);
+          bufferUInt32NoTag(length);
+          position = Utf8.encode(value, buffer, position, length);
+          totalBytesWritten += length;
+        }
+      } catch (UnpairedSurrogateException e) {
+        // Roll back the change and convert to an IOException.
+        totalBytesWritten -= position - oldPosition;
+        position = oldPosition;
+
+        // TODO(nathanmittler): We should throw an IOException here instead.
+        inefficientWriteStringNoTag(value, e);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void flush() throws IOException {
+      if (position > 0) {
+        // Flush the buffer.
+        doFlush();
+      }
+    }
+
+    @Override
+    public void write(byte[] value, int offset, int length) throws IOException {
+      flush();
+      out.write(value, offset, length);
+      totalBytesWritten += length;
+    }
+
+    @Override
+    public void writeLazy(byte[] value, int offset, int length) throws IOException {
+      flush();
+      out.writeLazy(value, offset, length);
+      totalBytesWritten += length;
+    }
+
+    @Override
+    public void write(ByteBuffer value) throws IOException {
+      flush();
+      int length = value.remaining();
+      out.write(value);
+      totalBytesWritten += length;
+    }
+
+    @Override
+    public void writeLazy(ByteBuffer value) throws IOException {
+      flush();
+      int length = value.remaining();
+      out.writeLazy(value);
+      totalBytesWritten += length;
+    }
+
+    private void flushIfNotAvailable(int requiredSize) throws IOException {
+      if (limit - position < requiredSize) {
+        doFlush();
+      }
+    }
+
+    private void doFlush() throws IOException {
+      out.write(buffer, 0, position);
+      position = 0;
+    }
+  }
+
+  /**
+   * An {@link CodedOutputStream} that decorates an {@link OutputStream}. It performs internal
+   * buffering to optimize writes to the {@link OutputStream}.
+   */
+  private static final class OutputStreamEncoder extends AbstractBufferedEncoder {
+    private final OutputStream out;
+
+    OutputStreamEncoder(OutputStream out, int bufferSize) {
+      super(bufferSize);
+      if (out == null) {
+        throw new NullPointerException("out");
+      }
+      this.out = out;
+    }
+
+    @Override
+    public void writeTag(final int fieldNumber, final int wireType) throws IOException {
+      writeUInt32NoTag(WireFormat.makeTag(fieldNumber, wireType));
+    }
+
+    @Override
+    public void writeInt32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferInt32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferUInt32NoTag(value);
+    }
+
+    @Override
+    public void writeFixed32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + FIXED_32_SIZE);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
+      bufferFixed32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt64(final int fieldNumber, final long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferUInt64NoTag(value);
+    }
+
+    @Override
+    public void writeFixed64(final int fieldNumber, final long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + FIXED_64_SIZE);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
+      bufferFixed64NoTag(value);
+    }
+
+    @Override
+    public void writeBool(final int fieldNumber, final boolean value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + 1);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      buffer((byte) (value ? 1 : 0));
+    }
+
+    @Override
+    public void writeString(final int fieldNumber, final String value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeStringNoTag(value);
+    }
+
+    @Override
+    public void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeBytesNoTag(value);
+    }
+
+    @Override
+    public void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
+      writeByteArray(fieldNumber, value, 0, value.length);
+    }
+
+    @Override
+    public void writeByteArray(
+        final int fieldNumber, final byte[] value, final int offset, final int length)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeByteArrayNoTag(value, offset, length);
+    }
+
+    @Override
+    public void writeByteBuffer(final int fieldNumber, final ByteBuffer value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeUInt32NoTag(value.capacity());
+      writeRawBytes(value);
+    }
+
+    @Override
+    public void writeBytesNoTag(final ByteString value) throws IOException {
+      writeUInt32NoTag(value.size());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void writeByteArrayNoTag(final byte[] value, int offset, int length) throws IOException {
+      writeUInt32NoTag(length);
+      write(value, offset, length);
+    }
+
+    @Override
+    public void writeRawBytes(final ByteBuffer value) throws IOException {
+      if (value.hasArray()) {
+        write(value.array(), value.arrayOffset(), value.capacity());
+      } else {
+        ByteBuffer duplicated = value.duplicate();
+        duplicated.clear();
+        write(duplicated);
+      }
+    }
+
+    @Override
+    public void writeMessage(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeMessageNoTag(value);
+    }
+
+    @Override
+    public void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeMessage(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeBytes(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeMessageNoTag(final MessageLite value) throws IOException {
+      writeUInt32NoTag(value.getSerializedSize());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void write(byte value) throws IOException {
+      if (position == limit) {
+        doFlush();
+      }
+
+      buffer(value);
+    }
+
+    @Override
+    public void writeInt32NoTag(int value) throws IOException {
+      if (value >= 0) {
+        writeUInt32NoTag(value);
+      } else {
+        // Must sign-extend.
+        writeUInt64NoTag(value);
+      }
+    }
+
+    @Override
+    public void writeUInt32NoTag(int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE);
+      bufferUInt32NoTag(value);
+    }
+
+    @Override
+    public void writeFixed32NoTag(final int value) throws IOException {
+      flushIfNotAvailable(FIXED_32_SIZE);
+      bufferFixed32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt64NoTag(long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE);
+      bufferUInt64NoTag(value);
+    }
+
+    @Override
+    public void writeFixed64NoTag(final long value) throws IOException {
+      flushIfNotAvailable(FIXED_64_SIZE);
+      bufferFixed64NoTag(value);
+    }
+
+    @Override
+    public void writeStringNoTag(String value) throws IOException {
+      try {
+        // UTF-8 byte length of the string is at least its UTF-16 code unit length (value.length()),
+        // and at most 3 times of it. We take advantage of this in both branches below.
+        final int maxLength = value.length() * Utf8.MAX_BYTES_PER_CHAR;
+        final int maxLengthVarIntSize = computeUInt32SizeNoTag(maxLength);
+
+        // If we are streaming and the potential length is too big to fit in our buffer, we take the
+        // slower path.
+        if (maxLengthVarIntSize + maxLength > limit) {
+          // Allocate a byte[] that we know can fit the string and encode into it. String.getBytes()
+          // does the same internally and then does *another copy* to return a byte[] of exactly the
+          // right size. We can skip that copy and just writeRawBytes up to the actualLength of the
+          // UTF-8 encoded bytes.
+          final byte[] encodedBytes = new byte[maxLength];
+          int actualLength = Utf8.encode(value, encodedBytes, 0, maxLength);
+          writeUInt32NoTag(actualLength);
+          writeLazy(encodedBytes, 0, actualLength);
+          return;
+        }
+
+        // Fast path: we have enough space available in our buffer for the string...
+        if (maxLengthVarIntSize + maxLength > limit - position) {
+          // Flush to free up space.
+          doFlush();
+        }
+
+        // Optimize for the case where we know this length results in a constant varint length as
+        // this saves a pass for measuring the length of the string.
+        final int minLengthVarIntSize = computeUInt32SizeNoTag(value.length());
+        int oldPosition = position;
+        final int length;
+        try {
+          if (minLengthVarIntSize == maxLengthVarIntSize) {
+            position = oldPosition + minLengthVarIntSize;
+            int newPosition = Utf8.encode(value, buffer, position, limit - position);
+            // Since this class is stateful and tracks the position, we rewind and store the
+            // state, prepend the length, then reset it back to the end of the string.
+            position = oldPosition;
+            length = newPosition - oldPosition - minLengthVarIntSize;
+            bufferUInt32NoTag(length);
+            position = newPosition;
+          } else {
+            length = Utf8.encodedLength(value);
+            bufferUInt32NoTag(length);
+            position = Utf8.encode(value, buffer, position, length);
+          }
+          totalBytesWritten += length;
+        } catch (UnpairedSurrogateException e) {
+          // Be extra careful and restore the original position for retrying the write with the
+          // less efficient path.
+          totalBytesWritten -= position - oldPosition;
+          position = oldPosition;
+          throw e;
+        } catch (ArrayIndexOutOfBoundsException e) {
+          throw new OutOfSpaceException(e);
+        }
+      } catch (UnpairedSurrogateException e) {
+        inefficientWriteStringNoTag(value, e);
+      }
+    }
+
+    @Override
+    public void flush() throws IOException {
+      if (position > 0) {
+        // Flush the buffer.
+        doFlush();
+      }
+    }
+
+    @Override
+    public void write(byte[] value, int offset, int length)
+        throws IOException {
+      if (limit - position >= length) {
+        // We have room in the current buffer.
+        System.arraycopy(value, offset, buffer, position, length);
+        position += length;
+        totalBytesWritten += length;
+      } else {
+        // Write extends past current buffer.  Fill the rest of this buffer and
+        // flush.
+        final int bytesWritten = limit - position;
+        System.arraycopy(value, offset, buffer, position, bytesWritten);
+        offset += bytesWritten;
+        length -= bytesWritten;
+        position = limit;
+        totalBytesWritten += bytesWritten;
+        doFlush();
+
+        // Now deal with the rest.
+        // Since we have an output stream, this is our buffer
+        // and buffer offset == 0
+        if (length <= limit) {
+          // Fits in new buffer.
+          System.arraycopy(value, offset, buffer, 0, length);
+          position = length;
+        } else {
+          // Write is very big.  Let's do it all at once.
+          out.write(value, offset, length);
+        }
+        totalBytesWritten += length;
+      }
+    }
+
+    @Override
+    public void writeLazy(byte[] value, int offset, int length) throws IOException {
+      write(value, offset, length);
+    }
+
+    @Override
+    public void write(ByteBuffer value) throws IOException {
+      int length = value.remaining();
+      if (limit - position >= length) {
+        // We have room in the current buffer.
+        value.get(buffer, position, length);
+        position += length;
+        totalBytesWritten += length;
+      } else {
+        // Write extends past current buffer.  Fill the rest of this buffer and
+        // flush.
+        final int bytesWritten = limit - position;
+        value.get(buffer, position, bytesWritten);
+        length -= bytesWritten;
+        position = limit;
+        totalBytesWritten += bytesWritten;
+        doFlush();
+
+        // Now deal with the rest.
+        // Since we have an output stream, this is our buffer
+        // and buffer offset == 0
+        while (length > limit) {
+          // Copy data into the buffer before writing it to OutputStream.
+          value.get(buffer, 0, limit);
+          out.write(buffer, 0, limit);
+          length -= limit;
+          totalBytesWritten += limit;
+        }
+        value.get(buffer, 0, length);
+        position = length;
+        totalBytesWritten += length;
+      }
+    }
+
+    @Override
+    public void writeLazy(ByteBuffer value) throws IOException {
+      write(value);
+    }
+
+    private void flushIfNotAvailable(int requiredSize) throws IOException {
+      if (limit - position < requiredSize) {
+        doFlush();
+      }
+    }
+
+    private void doFlush() throws IOException {
+      out.write(buffer, 0, position);
+      position = 0;
+    }
+  }
+
+  /**
+   * Gets the {@code sun.misc.Unsafe} instance, or {@code null} if not available on this
+   * platform.
+   */
+  private static sun.misc.Unsafe getUnsafe() {
+    sun.misc.Unsafe unsafe = null;
+    try {
+      unsafe = AccessController.doPrivileged(new PrivilegedExceptionAction<sun.misc.Unsafe>() {
+        @Override
+        public sun.misc.Unsafe run() throws Exception {
+          Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
+
+          for (Field f : k.getDeclaredFields()) {
+            f.setAccessible(true);
+            Object x = f.get(null);
+            if (k.isInstance(x)) {
+              return k.cast(x);
+            }
+          }
+          // The sun.misc.Unsafe field does not exist.
+          return null;
+        }
+      });
+    } catch (Throwable e) {
+      // Catching Throwable here due to the fact that Google AppEngine raises NoClassDefFoundError
+      // for Unsafe.
+    }
+
+    logger.log(Level.FINEST, "sun.misc.Unsafe: {}",
+        unsafe != null ? "available" : "unavailable");
+    return unsafe;
+  }
+
+  /**
+   * Indicates whether or not unsafe array operations are supported on this platform.
+   */
+  // TODO(nathanmittler): Add support for Android's MemoryBlock.
+  private static boolean supportsUnsafeArrayOperations() {
+    boolean supported = false;
+    if (UNSAFE != null) {
+      try {
+        UNSAFE.getClass().getMethod("arrayBaseOffset", Class.class);
+        UNSAFE.getClass().getMethod("putByte", Object.class, long.class, byte.class);
+        supported = true;
+      } catch (Throwable e) {
+        // Do nothing.
+      }
+    }
+    logger.log(Level.FINEST, "Unsafe array operations: {}",
+        supported ? "available" : "unavailable");
+    return supported;
+  }
+
+  /**
+   * Get the base offset for byte arrays, or {@code -1} if {@code sun.misc.Unsafe} is not
+   * available.
+   */
+  private static <T> int byteArrayBaseOffset() {
+    return HAS_UNSAFE_ARRAY_OPERATIONS ? UNSAFE.arrayBaseOffset(byte[].class) : -1;
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/Descriptors.java b/java/core/src/main/java/com/google/protobuf/Descriptors.java
index e303e138..e00ea342 100644
--- a/java/core/src/main/java/com/google/protobuf/Descriptors.java
+++ b/java/core/src/main/java/com/google/protobuf/Descriptors.java
@@ -74,16 +74,28 @@ public final class Descriptors {
    */
   public static final class FileDescriptor extends GenericDescriptor {
     /** Convert the descriptor to its protocol message representation. */
-    public FileDescriptorProto toProto() { return proto; }
+    @Override
+    public FileDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the file name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /** Returns this object. */
-    public FileDescriptor getFile() { return this; }
+    @Override
+    public FileDescriptor getFile() {
+      return this;
+    }
 
     /** Returns the same as getName(). */
-    public String getFullName() { return proto.getName(); }
+    @Override
+    public String getFullName() {
+      return proto.getName();
+    }
 
     /**
      * Get the proto package name.  This is the package name given by the
@@ -582,10 +594,16 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public DescriptorProto toProto() { return proto; }
+    @Override
+    public DescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the type's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /**
      * Get the type's fully-qualified name, within the proto language's
@@ -598,10 +616,16 @@ public final class Descriptors {
      * </pre>
      * {@code Baz}'s full name is "foo.bar.Baz".
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the {@link FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** If this is a nested type, get the outer descriptor, otherwise null. */
     public Descriptor getContainingType() { return containingType; }
@@ -875,19 +899,31 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public FieldDescriptorProto toProto() { return proto; }
+    @Override
+    public FieldDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the field's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /** Get the field's number. */
-    public int getNumber() { return proto.getNumber(); }
+    @Override
+    public int getNumber() {
+      return proto.getNumber();
+    }
 
     /**
      * Get the field's fully-qualified name.
      * @see Descriptors.Descriptor#getFullName()
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the JSON name of this field. */
     public String getJsonName() {
@@ -901,17 +937,22 @@ public final class Descriptors {
     public JavaType getJavaType() { return type.getJavaType(); }
 
     /** For internal use only. */
+    @Override
     public WireFormat.JavaType getLiteJavaType() {
       return getLiteType().getJavaType();
     }
 
     /** Get the {@code FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** Get the field's declared type. */
     public Type getType() { return type; }
 
     /** For internal use only. */
+    @Override
     public WireFormat.FieldType getLiteType() {
       return table[type.ordinal()];
     }
@@ -953,6 +994,7 @@ public final class Descriptors {
     }
 
     /** Is this field declared repeated? */
+    @Override
     public boolean isRepeated() {
       return proto.getLabel() == FieldDescriptorProto.Label.LABEL_REPEATED;
     }
@@ -960,6 +1002,7 @@ public final class Descriptors {
     /** Does this field have the {@code [packed = true]} option or is this field
      *  packable in proto3 and not explicitly setted to unpacked?
      */
+    @Override
     public boolean isPacked() {
       if (!isPackable()) {
         return false;
@@ -1048,6 +1091,7 @@ public final class Descriptors {
     }
 
     /** For enum fields, gets the field's type. */
+    @Override
     public EnumDescriptor getEnumType() {
       if (getJavaType() != JavaType.ENUM) {
         throw new UnsupportedOperationException(
@@ -1066,6 +1110,7 @@ public final class Descriptors {
      * @return negative, zero, or positive if {@code this} is less than,
      *         equal to, or greater than {@code other}, respectively.
      */
+    @Override
     public int compareTo(final FieldDescriptor other) {
       if (other.containingType != containingType) {
         throw new IllegalArgumentException(
@@ -1466,8 +1511,8 @@ public final class Descriptors {
      * For internal use only.  This is to satisfy the FieldDescriptorLite
      * interface.
      */
-    public MessageLite.Builder internalMergeFrom(
-        MessageLite.Builder to, MessageLite from) {
+    @Override
+    public MessageLite.Builder internalMergeFrom(MessageLite.Builder to, MessageLite from) {
       // FieldDescriptors are only used with non-lite messages so we can just
       // down-cast and call mergeFrom directly.
       return ((Message.Builder) to).mergeFrom((Message) from);
@@ -1487,19 +1532,31 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public EnumDescriptorProto toProto() { return proto; }
+    @Override
+    public EnumDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the type's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /**
      * Get the type's fully-qualified name.
      * @see Descriptors.Descriptor#getFullName()
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the {@link FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** If this is a nested type, get the outer descriptor, otherwise null. */
     public Descriptor getContainingType() { return containingType; }
@@ -1533,6 +1590,7 @@ public final class Descriptors {
      * @param number The value's number.
      * @return the value's descriptor, or {@code null} if not found.
      */
+    @Override
     public EnumValueDescriptor findValueByNumber(final int number) {
       return file.pool.enumValuesByNumber.get(
         new DescriptorPool.DescriptorIntPair(this, number));
@@ -1659,13 +1717,22 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public EnumValueDescriptorProto toProto() { return proto; }
+    @Override
+    public EnumValueDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the value's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /** Get the value's number. */
-    public int getNumber() { return proto.getNumber(); }
+    @Override
+    public int getNumber() {
+      return proto.getNumber();
+    }
 
     @Override
     public String toString() { return proto.getName(); }
@@ -1674,10 +1741,16 @@ public final class Descriptors {
      * Get the value's fully-qualified name.
      * @see Descriptors.Descriptor#getFullName()
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the {@link FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** Get the value's enum type. */
     public EnumDescriptor getType() { return type; }
@@ -1745,19 +1818,31 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public ServiceDescriptorProto toProto() { return proto; }
+    @Override
+    public ServiceDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the type's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /**
      * Get the type's fully-qualified name.
      * @see Descriptors.Descriptor#getFullName()
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the {@link FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** Get the {@code ServiceOptions}, defined in {@code descriptor.proto}. */
     public ServiceOptions getOptions() { return proto.getOptions(); }
@@ -1835,19 +1920,31 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public MethodDescriptorProto toProto() { return proto; }
+    @Override
+    public MethodDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the method's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /**
      * Get the method's fully-qualified name.
      * @see Descriptors.Descriptor#getFullName()
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the {@link FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** Get the method's service type. */
     public ServiceDescriptor getService() { return service; }
@@ -2248,10 +2345,22 @@ public final class Descriptors {
      * that has the same name as an existing package.
      */
     private static final class PackageDescriptor extends GenericDescriptor {
-      public Message toProto()        { return file.toProto(); }
-      public String getName()         { return name;           }
-      public String getFullName()     { return fullName;       }
-      public FileDescriptor getFile() { return file;           }
+      @Override
+      public Message toProto() {
+        return file.toProto();
+      }
+      @Override
+      public String getName() {
+        return name;
+      }
+      @Override
+      public String getFullName() {
+        return fullName;
+      }
+      @Override
+      public FileDescriptor getFile() {
+        return file;
+      }
 
       PackageDescriptor(final String name, final String fullName,
                         final FileDescriptor file) {
diff --git a/java/core/src/main/java/com/google/protobuf/DoubleArrayList.java b/java/core/src/main/java/com/google/protobuf/DoubleArrayList.java
index bcc9d6ee..a9543b83 100644
--- a/java/core/src/main/java/com/google/protobuf/DoubleArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/DoubleArrayList.java
@@ -34,7 +34,6 @@ import com.google.protobuf.Internal.DoubleList;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
 import java.util.RandomAccess;
 
 /**
@@ -45,8 +44,6 @@ import java.util.RandomAccess;
 final class DoubleArrayList
     extends AbstractProtobufList<Double> implements DoubleList, RandomAccess {
   
-  private static final int DEFAULT_CAPACITY = 10;
-  
   private static final DoubleArrayList EMPTY_LIST = new DoubleArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -71,32 +68,56 @@ final class DoubleArrayList
    * Constructs a new mutable {@code DoubleArrayList} with default capacity.
    */
   DoubleArrayList() {
-    this(DEFAULT_CAPACITY);
-  }
-
-  /**
-   * Constructs a new mutable {@code DoubleArrayList} with the provided capacity.
-   */
-  DoubleArrayList(int capacity) {
-    array = new double[capacity];
-    size = 0;
+    this(new double[DEFAULT_CAPACITY], 0);
   }
 
   /**
    * Constructs a new mutable {@code DoubleArrayList} containing the same elements as {@code other}.
    */
-  DoubleArrayList(List<Double> other) {
-    if (other instanceof DoubleArrayList) {
-      DoubleArrayList list = (DoubleArrayList) other;
-      array = list.array.clone();
-      size = list.size;
-    } else {
-      size = other.size();
-      array = new double[size];
-      for (int i = 0; i < size; i++) {
-        array[i] = other.get(i);
+  private DoubleArrayList(double[] array, int size) {
+    this.array = array;
+    this.size = size;
+  }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof DoubleArrayList)) {
+      return super.equals(o);
+    }
+    DoubleArrayList other = (DoubleArrayList) o;
+    if (size != other.size) {
+      return false;
+    }
+    
+    final double[] arr = other.array;
+    for (int i = 0; i < size; i++) {
+      if (array[i] != arr[i]) {
+        return false;
       }
     }
+    
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = 1;
+    for (int i = 0; i < size; i++) {
+      long bits = Double.doubleToLongBits(array[i]);
+      result = (31 * result) + Internal.hashLong(bits);
+    }
+    return result;
+  }
+
+  @Override
+  public DoubleList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size) {
+      throw new IllegalArgumentException();
+    }
+    return new DoubleArrayList(Arrays.copyOf(array, capacity), size);
   }
   
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/DynamicMessage.java b/java/core/src/main/java/com/google/protobuf/DynamicMessage.java
index 3ea1b688..859a9e8f 100644
--- a/java/core/src/main/java/com/google/protobuf/DynamicMessage.java
+++ b/java/core/src/main/java/com/google/protobuf/DynamicMessage.java
@@ -156,18 +156,22 @@ public final class DynamicMessage extends AbstractMessage {
   // -----------------------------------------------------------------
   // Implementation of Message interface.
 
+  @Override
   public Descriptor getDescriptorForType() {
     return type;
   }
 
+  @Override
   public DynamicMessage getDefaultInstanceForType() {
     return getDefaultInstance(type);
   }
 
+  @Override
   public Map<FieldDescriptor, Object> getAllFields() {
     return fields.getAllFields();
   }
 
+  @Override
   public boolean hasOneof(OneofDescriptor oneof) {
     verifyOneofContainingType(oneof);
     FieldDescriptor field = oneofCases[oneof.getIndex()];
@@ -177,16 +181,19 @@ public final class DynamicMessage extends AbstractMessage {
     return true;
   }
 
+  @Override
   public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
     verifyOneofContainingType(oneof);
     return oneofCases[oneof.getIndex()];
   }
 
+  @Override
   public boolean hasField(FieldDescriptor field) {
     verifyContainingType(field);
     return fields.hasField(field);
   }
 
+  @Override
   public Object getField(FieldDescriptor field) {
     verifyContainingType(field);
     Object result = fields.getField(field);
@@ -202,16 +209,19 @@ public final class DynamicMessage extends AbstractMessage {
     return result;
   }
 
+  @Override
   public int getRepeatedFieldCount(FieldDescriptor field) {
     verifyContainingType(field);
     return fields.getRepeatedFieldCount(field);
   }
 
+  @Override
   public Object getRepeatedField(FieldDescriptor field, int index) {
     verifyContainingType(field);
     return fields.getRepeatedField(field, index);
   }
 
+  @Override
   public UnknownFieldSet getUnknownFields() {
     return unknownFields;
   }
@@ -264,19 +274,22 @@ public final class DynamicMessage extends AbstractMessage {
     return size;
   }
 
+  @Override
   public Builder newBuilderForType() {
     return new Builder(type);
   }
 
+  @Override
   public Builder toBuilder() {
     return newBuilderForType().mergeFrom(this);
   }
 
+  @Override
   public Parser<DynamicMessage> getParserForType() {
     return new AbstractParser<DynamicMessage>() {
+      @Override
       public DynamicMessage parsePartialFrom(
-          CodedInputStream input,
-          ExtensionRegistryLite extensionRegistry)
+          CodedInputStream input, ExtensionRegistryLite extensionRegistry)
           throws InvalidProtocolBufferException {
         Builder builder = newBuilder(type);
         try {
@@ -370,6 +383,7 @@ public final class DynamicMessage extends AbstractMessage {
       }
     }
 
+    @Override
     public DynamicMessage build() {
       if (!isInitialized()) {
         throw newUninitializedMessageException(
@@ -394,6 +408,7 @@ public final class DynamicMessage extends AbstractMessage {
       return buildPartial();
     }
 
+    @Override
     public DynamicMessage buildPartial() {
       fields.makeImmutable();
       DynamicMessage result =
@@ -411,22 +426,27 @@ public final class DynamicMessage extends AbstractMessage {
       return result;
     }
 
+    @Override
     public boolean isInitialized() {
       return DynamicMessage.isInitialized(type, fields);
     }
 
+    @Override
     public Descriptor getDescriptorForType() {
       return type;
     }
 
+    @Override
     public DynamicMessage getDefaultInstanceForType() {
       return getDefaultInstance(type);
     }
 
+    @Override
     public Map<FieldDescriptor, Object> getAllFields() {
       return fields.getAllFields();
     }
 
+    @Override
     public Builder newBuilderForField(FieldDescriptor field) {
       verifyContainingType(field);
 
@@ -438,6 +458,7 @@ public final class DynamicMessage extends AbstractMessage {
       return new Builder(field.getMessageType());
     }
 
+    @Override
     public boolean hasOneof(OneofDescriptor oneof) {
       verifyOneofContainingType(oneof);
       FieldDescriptor field = oneofCases[oneof.getIndex()];
@@ -447,11 +468,13 @@ public final class DynamicMessage extends AbstractMessage {
       return true;
     }
 
+    @Override
     public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
       verifyOneofContainingType(oneof);
       return oneofCases[oneof.getIndex()];
     }
 
+    @Override
     public Builder clearOneof(OneofDescriptor oneof) {
       verifyOneofContainingType(oneof);
       FieldDescriptor field = oneofCases[oneof.getIndex()];
@@ -461,11 +484,13 @@ public final class DynamicMessage extends AbstractMessage {
       return this;
     }
 
+    @Override
     public boolean hasField(FieldDescriptor field) {
       verifyContainingType(field);
       return fields.hasField(field);
     }
 
+    @Override
     public Object getField(FieldDescriptor field) {
       verifyContainingType(field);
       Object result = fields.getField(field);
@@ -481,6 +506,7 @@ public final class DynamicMessage extends AbstractMessage {
       return result;
     }
 
+    @Override
     public Builder setField(FieldDescriptor field, Object value) {
       verifyContainingType(field);
       ensureIsMutable();
@@ -505,6 +531,7 @@ public final class DynamicMessage extends AbstractMessage {
       return this;
     }
 
+    @Override
     public Builder clearField(FieldDescriptor field) {
       verifyContainingType(field);
       ensureIsMutable();
@@ -519,24 +546,27 @@ public final class DynamicMessage extends AbstractMessage {
       return this;
     }
 
+    @Override
     public int getRepeatedFieldCount(FieldDescriptor field) {
       verifyContainingType(field);
       return fields.getRepeatedFieldCount(field);
     }
 
+    @Override
     public Object getRepeatedField(FieldDescriptor field, int index) {
       verifyContainingType(field);
       return fields.getRepeatedField(field, index);
     }
 
-    public Builder setRepeatedField(FieldDescriptor field,
-                                    int index, Object value) {
+    @Override
+    public Builder setRepeatedField(FieldDescriptor field, int index, Object value) {
       verifyContainingType(field);
       ensureIsMutable();
       fields.setRepeatedField(field, index, value);
       return this;
     }
 
+    @Override
     public Builder addRepeatedField(FieldDescriptor field, Object value) {
       verifyContainingType(field);
       ensureIsMutable();
@@ -544,10 +574,12 @@ public final class DynamicMessage extends AbstractMessage {
       return this;
     }
 
+    @Override
     public UnknownFieldSet getUnknownFields() {
       return unknownFields;
     }
 
+    @Override
     public Builder setUnknownFields(UnknownFieldSet unknownFields) {
       if (getDescriptorForType().getFile().getSyntax()
           == Descriptors.FileDescriptor.Syntax.PROTO3) {
diff --git a/java/core/src/main/java/com/google/protobuf/Extension.java b/java/core/src/main/java/com/google/protobuf/Extension.java
index 68d29f33..08ec5b45 100644
--- a/java/core/src/main/java/com/google/protobuf/Extension.java
+++ b/java/core/src/main/java/com/google/protobuf/Extension.java
@@ -42,6 +42,7 @@ public abstract class Extension<ContainingType extends MessageLite, Type>
   public abstract Descriptors.FieldDescriptor getDescriptor();
 
   /** Returns whether or not this extension is a Lite Extension. */
+  @Override
   final boolean isLite() {
     return false;
   }
diff --git a/java/core/src/main/java/com/google/protobuf/FieldSet.java b/java/core/src/main/java/com/google/protobuf/FieldSet.java
index 47924b65..4e89709f 100644
--- a/java/core/src/main/java/com/google/protobuf/FieldSet.java
+++ b/java/core/src/main/java/com/google/protobuf/FieldSet.java
@@ -120,6 +120,25 @@ final class FieldSet<FieldDescriptorType extends
   public boolean isImmutable() {
     return isImmutable;
   }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    
+    if (!(o instanceof FieldSet)) {
+      return false;
+    }
+    
+    FieldSet<?> other = (FieldSet<?>) o;
+    return other.fields.equals(other.fields);
+  }
+  
+  @Override
+  public int hashCode() {
+    return fields.hashCode();
+  }
 
   /**
    * Clones the FieldSet. The returned FieldSet will be mutable even if the
diff --git a/java/core/src/main/java/com/google/protobuf/FloatArrayList.java b/java/core/src/main/java/com/google/protobuf/FloatArrayList.java
index 033b5eed..63cb6d77 100644
--- a/java/core/src/main/java/com/google/protobuf/FloatArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/FloatArrayList.java
@@ -34,7 +34,6 @@ import com.google.protobuf.Internal.FloatList;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
 import java.util.RandomAccess;
 
 /**
@@ -44,8 +43,6 @@ import java.util.RandomAccess;
  */
 final class FloatArrayList extends AbstractProtobufList<Float> implements FloatList, RandomAccess {
   
-  private static final int DEFAULT_CAPACITY = 10;
-  
   private static final FloatArrayList EMPTY_LIST = new FloatArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -70,32 +67,55 @@ final class FloatArrayList extends AbstractProtobufList<Float> implements FloatL
    * Constructs a new mutable {@code FloatArrayList} with default capacity.
    */
   FloatArrayList() {
-    this(DEFAULT_CAPACITY);
-  }
-
-  /**
-   * Constructs a new mutable {@code FloatArrayList} with the provided capacity.
-   */
-  FloatArrayList(int capacity) {
-    array = new float[capacity];
-    size = 0;
+    this(new float[DEFAULT_CAPACITY], 0);
   }
 
   /**
    * Constructs a new mutable {@code FloatArrayList} containing the same elements as {@code other}.
    */
-  FloatArrayList(List<Float> other) {
-    if (other instanceof FloatArrayList) {
-      FloatArrayList list = (FloatArrayList) other;
-      array = list.array.clone();
-      size = list.size;
-    } else {
-      size = other.size();
-      array = new float[size];
-      for (int i = 0; i < size; i++) {
-        array[i] = other.get(i);
+  private FloatArrayList(float[] array, int size) {
+    this.array = array;
+    this.size = size;
+  }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof FloatArrayList)) {
+      return super.equals(o);
+    }
+    FloatArrayList other = (FloatArrayList) o;
+    if (size != other.size) {
+      return false;
+    }
+    
+    final float[] arr = other.array;
+    for (int i = 0; i < size; i++) {
+      if (array[i] != arr[i]) {
+        return false;
       }
     }
+    
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = 1;
+    for (int i = 0; i < size; i++) {
+      result = (31 * result) + Float.floatToIntBits(array[i]);
+    }
+    return result;
+  }
+
+  @Override
+  public FloatList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size) {
+      throw new IllegalArgumentException();
+    }
+    return new FloatArrayList(Arrays.copyOf(array, capacity), size);
   }
   
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java b/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
index a50afe55..57e732a0 100644
--- a/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
+++ b/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
@@ -80,6 +80,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     unknownFields = builder.getUnknownFields();
   }
 
+  @Override
   public Parser<? extends GeneratedMessage> getParserForType() {
     throw new UnsupportedOperationException(
         "This is supposed to be overridden by subclasses.");
@@ -102,7 +103,7 @@ public abstract class GeneratedMessage extends AbstractMessage
    */
   protected abstract FieldAccessorTable internalGetFieldAccessorTable();
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public Descriptor getDescriptorForType() {
     return internalGetFieldAccessorTable().descriptor;
   }
@@ -191,7 +192,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     return true;
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public Map<FieldDescriptor, Object> getAllFields() {
     return Collections.unmodifiableMap(
         getAllFieldsMutable(/* getBytesForString = */ false));
@@ -212,22 +213,22 @@ public abstract class GeneratedMessage extends AbstractMessage
         getAllFieldsMutable(/* getBytesForString = */ true));
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public boolean hasOneof(final OneofDescriptor oneof) {
     return internalGetFieldAccessorTable().getOneof(oneof).has(this);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public FieldDescriptor getOneofFieldDescriptor(final OneofDescriptor oneof) {
     return internalGetFieldAccessorTable().getOneof(oneof).get(this);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public boolean hasField(final FieldDescriptor field) {
     return internalGetFieldAccessorTable().getField(field).has(this);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public Object getField(final FieldDescriptor field) {
     return internalGetFieldAccessorTable().getField(field).get(this);
   }
@@ -244,19 +245,19 @@ public abstract class GeneratedMessage extends AbstractMessage
     return internalGetFieldAccessorTable().getField(field).getRaw(this);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public int getRepeatedFieldCount(final FieldDescriptor field) {
     return internalGetFieldAccessorTable().getField(field)
       .getRepeatedCount(this);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public Object getRepeatedField(final FieldDescriptor field, final int index) {
     return internalGetFieldAccessorTable().getField(field)
       .getRepeated(this, index);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public UnknownFieldSet getUnknownFields() {
     throw new UnsupportedOperationException(
         "This is supposed to be overridden by subclasses.");
@@ -380,7 +381,7 @@ public abstract class GeneratedMessage extends AbstractMessage
   }
 
   @SuppressWarnings("unchecked")
-  public abstract static class Builder <BuilderType extends Builder>
+  public abstract static class Builder <BuilderType extends Builder<BuilderType>>
       extends AbstractMessage.Builder<BuilderType> {
 
     private BuilderParent builderParent;
@@ -444,6 +445,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      * Called by the initialization and clear code paths to allow subclasses to
      * reset any of their builtin fields back to the initial values.
      */
+    @Override
     public BuilderType clear() {
       unknownFields = UnknownFieldSet.getDefaultInstance();
       onChanged();
@@ -457,12 +459,12 @@ public abstract class GeneratedMessage extends AbstractMessage
      */
     protected abstract FieldAccessorTable internalGetFieldAccessorTable();
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public Descriptor getDescriptorForType() {
       return internalGetFieldAccessorTable().descriptor;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public Map<FieldDescriptor, Object> getAllFields() {
       return Collections.unmodifiableMap(getAllFieldsMutable());
     }
@@ -510,39 +512,38 @@ public abstract class GeneratedMessage extends AbstractMessage
       return result;
     }
 
-    public Message.Builder newBuilderForField(
-        final FieldDescriptor field) {
+    @Override
+    public Message.Builder newBuilderForField(final FieldDescriptor field) {
       return internalGetFieldAccessorTable().getField(field).newBuilder();
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public Message.Builder getFieldBuilder(final FieldDescriptor field) {
       return internalGetFieldAccessorTable().getField(field).getBuilder(this);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field,
-        int index) {
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
       return internalGetFieldAccessorTable().getField(field).getRepeatedBuilder(
           this, index);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public boolean hasOneof(final OneofDescriptor oneof) {
       return internalGetFieldAccessorTable().getOneof(oneof).has(this);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public FieldDescriptor getOneofFieldDescriptor(final OneofDescriptor oneof) {
       return internalGetFieldAccessorTable().getOneof(oneof).get(this);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public boolean hasField(final FieldDescriptor field) {
       return internalGetFieldAccessorTable().getField(field).has(this);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public Object getField(final FieldDescriptor field) {
       Object object = internalGetFieldAccessorTable().getField(field).get(this);
       if (field.isRepeated()) {
@@ -554,52 +555,52 @@ public abstract class GeneratedMessage extends AbstractMessage
       }
     }
 
-    public BuilderType setField(final FieldDescriptor field,
-                                final Object value) {
+    @Override
+    public BuilderType setField(final FieldDescriptor field, final Object value) {
       internalGetFieldAccessorTable().getField(field).set(this, value);
       return (BuilderType) this;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public BuilderType clearField(final FieldDescriptor field) {
       internalGetFieldAccessorTable().getField(field).clear(this);
       return (BuilderType) this;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public BuilderType clearOneof(final OneofDescriptor oneof) {
       internalGetFieldAccessorTable().getOneof(oneof).clear(this);
       return (BuilderType) this;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public int getRepeatedFieldCount(final FieldDescriptor field) {
       return internalGetFieldAccessorTable().getField(field)
           .getRepeatedCount(this);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public Object getRepeatedField(final FieldDescriptor field,
-                                   final int index) {
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
       return internalGetFieldAccessorTable().getField(field)
           .getRepeated(this, index);
     }
 
-    public BuilderType setRepeatedField(final FieldDescriptor field,
-                                        final int index, final Object value) {
+    @Override
+    public BuilderType setRepeatedField(
+        final FieldDescriptor field, final int index, final Object value) {
       internalGetFieldAccessorTable().getField(field)
         .setRepeated(this, index, value);
       return (BuilderType) this;
     }
 
-    public BuilderType addRepeatedField(final FieldDescriptor field,
-                                        final Object value) {
+    @Override
+    public BuilderType addRepeatedField(final FieldDescriptor field, final Object value) {
       internalGetFieldAccessorTable().getField(field).addRepeated(this, value);
       return (BuilderType) this;
     }
 
-    public BuilderType setUnknownFields(
-        final UnknownFieldSet unknownFields) {
+    @Override
+    public BuilderType setUnknownFields(final UnknownFieldSet unknownFields) {
       this.unknownFields = unknownFields;
       onChanged();
       return (BuilderType) this;
@@ -616,7 +617,7 @@ public abstract class GeneratedMessage extends AbstractMessage
       return (BuilderType) this;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public boolean isInitialized() {
       for (final FieldDescriptor field : getDescriptorForType().getFields()) {
         // Check that all required fields are present.
@@ -646,7 +647,7 @@ public abstract class GeneratedMessage extends AbstractMessage
       return true;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final UnknownFieldSet getUnknownFields() {
       return unknownFields;
     }
@@ -670,7 +671,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      */
     private class BuilderParentImpl implements BuilderParent {
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public void markDirty() {
         onChanged();
       }
@@ -735,6 +736,7 @@ public abstract class GeneratedMessage extends AbstractMessage
   public interface ExtendableMessageOrBuilder<
       MessageType extends ExtendableMessage> extends MessageOrBuilder {
     // Re-define for return type covariance.
+    @Override
     Message getDefaultInstanceForType();
 
     /** Check if a singular extension is present. */
@@ -821,9 +823,8 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Check if a singular extension is present. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public final <Type> boolean hasExtension(
-        final ExtensionLite<MessageType, Type> extensionLite) {
+    @Override
+    public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extensionLite) {
       Extension<MessageType, Type> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -831,7 +832,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get the number of elements in a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final <Type> int getExtensionCount(
         final ExtensionLite<MessageType, List<Type>> extensionLite) {
       Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
@@ -842,10 +843,9 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get the value of an extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     @SuppressWarnings("unchecked")
-    public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, Type> extensionLite) {
+    public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extensionLite) {
       Extension<MessageType, Type> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -867,11 +867,10 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get one element of a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     @SuppressWarnings("unchecked")
     public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, List<Type>> extensionLite,
-        final int index) {
+        final ExtensionLite<MessageType, List<Type>> extensionLite, final int index) {
       Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -1105,7 +1104,7 @@ public abstract class GeneratedMessage extends AbstractMessage
   @SuppressWarnings("unchecked")
   public abstract static class ExtendableBuilder<
         MessageType extends ExtendableMessage,
-        BuilderType extends ExtendableBuilder>
+        BuilderType extends ExtendableBuilder<MessageType, BuilderType>>
       extends Builder<BuilderType>
       implements ExtendableMessageOrBuilder<MessageType> {
 
@@ -1157,9 +1156,8 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Check if a singular extension is present. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public final <Type> boolean hasExtension(
-        final ExtensionLite<MessageType, Type> extensionLite) {
+    @Override
+    public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extensionLite) {
       Extension<MessageType, Type> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -1167,7 +1165,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get the number of elements in a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final <Type> int getExtensionCount(
         final ExtensionLite<MessageType, List<Type>> extensionLite) {
       Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
@@ -1178,9 +1176,8 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get the value of an extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, Type> extensionLite) {
+    @Override
+    public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extensionLite) {
       Extension<MessageType, Type> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -1202,10 +1199,9 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get one element of a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, List<Type>> extensionLite,
-        final int index) {
+        final ExtensionLite<MessageType, List<Type>> extensionLite, final int index) {
       Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -1458,10 +1454,9 @@ public abstract class GeneratedMessage extends AbstractMessage
     // obtained.
     return new GeneratedExtension<ContainingType, Type>(
         new CachedDescriptorRetriever() {
-          //@Override (Java 1.6 override semantics, but we must support 1.5)
+          @Override
           public FieldDescriptor loadDescriptor() {
-            return scope.getDescriptorForType().getExtensions()
-                .get(descriptorIndex);
+            return scope.getDescriptorForType().getExtensions().get(descriptorIndex);
           }
         },
         singularType,
@@ -1489,6 +1484,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     private volatile FieldDescriptor descriptor;
     protected abstract FieldDescriptor loadDescriptor();
 
+    @Override
     public FieldDescriptor getDescriptor() {
       if (descriptor == null) {
         synchronized (this) {
@@ -1518,6 +1514,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     // obtained.
     return new GeneratedExtension<ContainingType, Type>(
         new CachedDescriptorRetriever() {
+          @Override
           protected FieldDescriptor loadDescriptor() {
             return scope.getDescriptorForType().findFieldByName(name);
           }
@@ -1544,17 +1541,18 @@ public abstract class GeneratedMessage extends AbstractMessage
     // used to obtain the extension's FieldDescriptor.
     return new GeneratedExtension<ContainingType, Type>(
         new CachedDescriptorRetriever() {
+          @Override
           protected FieldDescriptor loadDescriptor() {
             try {
-              Class clazz =
-                  singularType.getClassLoader().loadClass(descriptorOuterClass);
-              FileDescriptor file =
-                  (FileDescriptor) clazz.getField("descriptor").get(null);
+              Class clazz = singularType.getClassLoader().loadClass(descriptorOuterClass);
+              FileDescriptor file = (FileDescriptor) clazz.getField("descriptor").get(null);
               return file.findExtensionByName(extensionName);
             } catch (Exception e) {
               throw new RuntimeException(
-                  "Cannot load descriptors: " + descriptorOuterClass +
-                  " is not a valid descriptor class name", e);
+                  "Cannot load descriptors: "
+                      + descriptorOuterClass
+                      + " is not a valid descriptor class name",
+                  e);
             }
           }
         },
@@ -1636,12 +1634,13 @@ public abstract class GeneratedMessage extends AbstractMessage
       if (descriptorRetriever != null) {
         throw new IllegalStateException("Already initialized.");
       }
-      descriptorRetriever = new ExtensionDescriptorRetriever() {
-          //@Override (Java 1.6 override semantics, but we must support 1.5)
-          public FieldDescriptor getDescriptor() {
-            return descriptor;
-          }
-        };
+      descriptorRetriever =
+          new ExtensionDescriptorRetriever() {
+            @Override
+            public FieldDescriptor getDescriptor() {
+              return descriptor;
+            }
+          };
     }
 
     private ExtensionDescriptorRetriever descriptorRetriever;
@@ -1651,6 +1650,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     private final Method enumGetValueDescriptor;
     private final ExtensionType extensionType;
 
+    @Override
     public FieldDescriptor getDescriptor() {
       if (descriptorRetriever == null) {
         throw new IllegalStateException(
@@ -1663,10 +1663,12 @@ public abstract class GeneratedMessage extends AbstractMessage
      * If the extension is an embedded message or group, returns the default
      * instance of the message.
      */
+    @Override
     public Message getMessageDefaultInstance() {
       return messageDefaultInstance;
     }
 
+    @Override
     protected ExtensionType getExtensionType() {
       return extensionType;
     }
@@ -1677,7 +1679,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      * EnumValueDescriptors but the native accessors use the generated enum
      * type.
      */
-    // @Override
+    @Override
     @SuppressWarnings("unchecked")
     protected Object fromReflectionType(final Object value) {
       FieldDescriptor descriptor = getDescriptor();
@@ -1702,7 +1704,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      * Like {@link #fromReflectionType(Object)}, but if the type is a repeated
      * type, this converts a single element.
      */
-    // @Override
+    @Override
     protected Object singularFromReflectionType(final Object value) {
       FieldDescriptor descriptor = getDescriptor();
       switch (descriptor.getJavaType()) {
@@ -1726,7 +1728,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      * EnumValueDescriptors but the native accessors use the generated enum
      * type.
      */
-    // @Override
+    @Override
     @SuppressWarnings("unchecked")
     protected Object toReflectionType(final Object value) {
       FieldDescriptor descriptor = getDescriptor();
@@ -1750,7 +1752,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      * Like {@link #toReflectionType(Object)}, but if the type is a repeated
      * type, this converts a single element.
      */
-    // @Override
+    @Override
     protected Object singularToReflectionType(final Object value) {
       FieldDescriptor descriptor = getDescriptor();
       switch (descriptor.getJavaType()) {
@@ -1761,22 +1763,22 @@ public abstract class GeneratedMessage extends AbstractMessage
       }
     }
 
-    // @Override
+    @Override
     public int getNumber() {
       return getDescriptor().getNumber();
     }
 
-    // @Override
+    @Override
     public WireFormat.FieldType getLiteType() {
       return getDescriptor().getLiteType();
     }
 
-    // @Override
+    @Override
     public boolean isRepeated() {
       return getDescriptor().isRepeated();
     }
 
-    // @Override
+    @Override
     @SuppressWarnings("unchecked")
     public Type getDefaultValue() {
       if (isRepeated()) {
@@ -2126,49 +2128,57 @@ public abstract class GeneratedMessage extends AbstractMessage
         return ((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber();
       }
 
+      @Override
       public Object get(final GeneratedMessage message) {
         return invokeOrDie(getMethod, message);
       }
+      @Override
       public Object get(GeneratedMessage.Builder builder) {
         return invokeOrDie(getMethodBuilder, builder);
       }
+      @Override
       public Object getRaw(final GeneratedMessage message) {
         return get(message);
       }
+      @Override
       public Object getRaw(GeneratedMessage.Builder builder) {
         return get(builder);
       }
+      @Override
       public void set(final Builder builder, final Object value) {
         invokeOrDie(setMethod, builder, value);
       }
-      public Object getRepeated(final GeneratedMessage message,
-                                final int index) {
+      @Override
+      public Object getRepeated(final GeneratedMessage message, final int index) {
         throw new UnsupportedOperationException(
           "getRepeatedField() called on a singular field.");
       }
-      public Object getRepeatedRaw(final GeneratedMessage message,
-                                final int index) {
+      @Override
+      public Object getRepeatedRaw(final GeneratedMessage message, final int index) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldRaw() called on a singular field.");
       }
+      @Override
       public Object getRepeated(GeneratedMessage.Builder builder, int index) {
         throw new UnsupportedOperationException(
           "getRepeatedField() called on a singular field.");
       }
-      public Object getRepeatedRaw(GeneratedMessage.Builder builder,
-          int index) {
+      @Override
+      public Object getRepeatedRaw(GeneratedMessage.Builder builder, int index) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldRaw() called on a singular field.");
       }
-      public void setRepeated(final Builder builder, final int index,
-          final Object value) {
+      @Override
+      public void setRepeated(final Builder builder, final int index, final Object value) {
         throw new UnsupportedOperationException(
           "setRepeatedField() called on a singular field.");
       }
+      @Override
       public void addRepeated(final Builder builder, final Object value) {
         throw new UnsupportedOperationException(
           "addRepeatedField() called on a singular field.");
       }
+      @Override
       public boolean has(final GeneratedMessage message) {
         if (!hasHasMethod) {
           if (isOneofField) {
@@ -2178,6 +2188,7 @@ public abstract class GeneratedMessage extends AbstractMessage
         }
         return (Boolean) invokeOrDie(hasMethod, message);
       }
+      @Override
       public boolean has(GeneratedMessage.Builder builder) {
         if (!hasHasMethod) {
           if (isOneofField) {
@@ -2187,27 +2198,32 @@ public abstract class GeneratedMessage extends AbstractMessage
         }
         return (Boolean) invokeOrDie(hasMethodBuilder, builder);
       }
+      @Override
       public int getRepeatedCount(final GeneratedMessage message) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldSize() called on a singular field.");
       }
+      @Override
       public int getRepeatedCount(GeneratedMessage.Builder builder) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldSize() called on a singular field.");
       }
+      @Override
       public void clear(final Builder builder) {
         invokeOrDie(clearMethod, builder);
       }
+      @Override
       public Message.Builder newBuilder() {
         throw new UnsupportedOperationException(
           "newBuilderForField() called on a non-Message type.");
       }
+      @Override
       public Message.Builder getBuilder(GeneratedMessage.Builder builder) {
         throw new UnsupportedOperationException(
           "getFieldBuilder() called on a non-Message type.");
       }
-      public Message.Builder getRepeatedBuilder(GeneratedMessage.Builder builder,
-          int index) {
+      @Override
+      public Message.Builder getRepeatedBuilder(GeneratedMessage.Builder builder, int index) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldBuilder() called on a non-Message type.");
       }
@@ -2251,18 +2267,23 @@ public abstract class GeneratedMessage extends AbstractMessage
         clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
       }
 
+      @Override
       public Object get(final GeneratedMessage message) {
         return invokeOrDie(getMethod, message);
       }
+      @Override
       public Object get(GeneratedMessage.Builder builder) {
         return invokeOrDie(getMethodBuilder, builder);
       }
+      @Override
       public Object getRaw(final GeneratedMessage message) {
         return get(message);
       }
+      @Override
       public Object getRaw(GeneratedMessage.Builder builder) {
         return get(builder);
       }
+      @Override
       public void set(final Builder builder, final Object value) {
         // Add all the elements individually.  This serves two purposes:
         // 1) Verifies that each element has the correct type.
@@ -2273,54 +2294,64 @@ public abstract class GeneratedMessage extends AbstractMessage
           addRepeated(builder, element);
         }
       }
-      public Object getRepeated(final GeneratedMessage message,
-                                final int index) {
+      @Override
+      public Object getRepeated(final GeneratedMessage message, final int index) {
         return invokeOrDie(getRepeatedMethod, message, index);
       }
+      @Override
       public Object getRepeated(GeneratedMessage.Builder builder, int index) {
         return invokeOrDie(getRepeatedMethodBuilder, builder, index);
       }
+      @Override
       public Object getRepeatedRaw(GeneratedMessage message, int index) {
         return getRepeated(message, index);
       }
-      public Object getRepeatedRaw(GeneratedMessage.Builder builder,
-          int index) {
+      @Override
+      public Object getRepeatedRaw(GeneratedMessage.Builder builder, int index) {
         return getRepeated(builder, index);
       }
-      public void setRepeated(final Builder builder,
-                              final int index, final Object value) {
+      @Override
+      public void setRepeated(final Builder builder, final int index, final Object value) {
         invokeOrDie(setRepeatedMethod, builder, index, value);
       }
+      @Override
       public void addRepeated(final Builder builder, final Object value) {
         invokeOrDie(addRepeatedMethod, builder, value);
       }
+      @Override
       public boolean has(final GeneratedMessage message) {
         throw new UnsupportedOperationException(
           "hasField() called on a repeated field.");
       }
+      @Override
       public boolean has(GeneratedMessage.Builder builder) {
         throw new UnsupportedOperationException(
           "hasField() called on a repeated field.");
       }
+      @Override
       public int getRepeatedCount(final GeneratedMessage message) {
         return (Integer) invokeOrDie(getCountMethod, message);
       }
+      @Override
       public int getRepeatedCount(GeneratedMessage.Builder builder) {
         return (Integer) invokeOrDie(getCountMethodBuilder, builder);
       }
+      @Override
       public void clear(final Builder builder) {
         invokeOrDie(clearMethod, builder);
       }
+      @Override
       public Message.Builder newBuilder() {
         throw new UnsupportedOperationException(
           "newBuilderForField() called on a non-Message type.");
       }
+      @Override
       public Message.Builder getBuilder(GeneratedMessage.Builder builder) {
         throw new UnsupportedOperationException(
           "getFieldBuilder() called on a non-Message type.");
       }
-      public Message.Builder getRepeatedBuilder(GeneratedMessage.Builder builder,
-          int index) {
+      @Override
+      public Message.Builder getRepeatedBuilder(GeneratedMessage.Builder builder, int index) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldBuilder() called on a non-Message type.");
       }
@@ -2357,6 +2388,7 @@ public abstract class GeneratedMessage extends AbstractMessage
             field.getNumber());
       }
 
+      @Override
       public Object get(GeneratedMessage message) {
         List result = new ArrayList();
         for (int i = 0; i < getRepeatedCount(message); i++) {
@@ -2365,6 +2397,7 @@ public abstract class GeneratedMessage extends AbstractMessage
         return Collections.unmodifiableList(result);
       }
 
+      @Override
       public Object get(Builder builder) {
         List result = new ArrayList();
         for (int i = 0; i < getRepeatedCount(builder); i++) {
@@ -2373,14 +2406,17 @@ public abstract class GeneratedMessage extends AbstractMessage
         return Collections.unmodifiableList(result);
       }
 
+      @Override
       public Object getRaw(GeneratedMessage message) {
         return get(message);
       }
 
+      @Override
       public Object getRaw(GeneratedMessage.Builder builder) {
         return get(builder);
       }
 
+      @Override
       public void set(Builder builder, Object value) {
         clear(builder);
         for (Object entry : (List) value) {
@@ -2388,63 +2424,76 @@ public abstract class GeneratedMessage extends AbstractMessage
         }
       }
 
+      @Override
       public Object getRepeated(GeneratedMessage message, int index) {
         return getMapField(message).getList().get(index);
       }
 
+      @Override
       public Object getRepeated(Builder builder, int index) {
         return getMapField(builder).getList().get(index);
       }
 
+      @Override
       public Object getRepeatedRaw(GeneratedMessage message, int index) {
         return getRepeated(message, index);
       }
 
+      @Override
       public Object getRepeatedRaw(Builder builder, int index) {
         return getRepeated(builder, index);
       }
 
+      @Override
       public void setRepeated(Builder builder, int index, Object value) {
         getMutableMapField(builder).getMutableList().set(index, (Message) value);
       }
 
+      @Override
       public void addRepeated(Builder builder, Object value) {
         getMutableMapField(builder).getMutableList().add((Message) value);
       }
 
+      @Override
       public boolean has(GeneratedMessage message) {
         throw new UnsupportedOperationException(
             "hasField() is not supported for repeated fields.");
       }
 
+      @Override
       public boolean has(Builder builder) {
         throw new UnsupportedOperationException(
             "hasField() is not supported for repeated fields.");
       }
 
+      @Override
       public int getRepeatedCount(GeneratedMessage message) {
         return getMapField(message).getList().size();
       }
 
+      @Override
       public int getRepeatedCount(Builder builder) {
         return getMapField(builder).getList().size();
       }
 
+      @Override
       public void clear(Builder builder) {
         getMutableMapField(builder).getMutableList().clear();
       }
 
+      @Override
       public com.google.protobuf.Message.Builder newBuilder() {
         return mapEntryMessageDefaultInstance.newBuilderForType();
       }
 
+      @Override
       public com.google.protobuf.Message.Builder getBuilder(Builder builder) {
         throw new UnsupportedOperationException(
             "Nested builder not supported for map fields.");
       }
 
-      public com.google.protobuf.Message.Builder getRepeatedBuilder(
-          Builder builder, int index) {
+      @Override
+      public com.google.protobuf.Message.Builder getRepeatedBuilder(Builder builder, int index) {
         throw new UnsupportedOperationException(
             "Nested builder not supported for map fields.");
       }
diff --git a/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java b/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
index 12a1472d..c5adc5ad 100644
--- a/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
+++ b/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
@@ -31,6 +31,7 @@
 package com.google.protobuf;
 
 import com.google.protobuf.AbstractMessageLite.Builder.LimitedInputStream;
+import com.google.protobuf.GeneratedMessageLite.EqualsVisitor.NotEqualsException;
 import com.google.protobuf.Internal.BooleanList;
 import com.google.protobuf.Internal.DoubleList;
 import com.google.protobuf.Internal.FloatList;
@@ -59,24 +60,27 @@ import java.util.Map;
 public abstract class GeneratedMessageLite<
     MessageType extends GeneratedMessageLite<MessageType, BuilderType>,
     BuilderType extends GeneratedMessageLite.Builder<MessageType, BuilderType>> 
-        extends AbstractMessageLite {
+        extends AbstractMessageLite<MessageType, BuilderType> {
 
   /** For use by generated code only. Lazily initialized to reduce allocations. */
-  protected UnknownFieldSetLite unknownFields = null;
+  protected UnknownFieldSetLite unknownFields = UnknownFieldSetLite.getDefaultInstance();
   
   /** For use by generated code only.  */
   protected int memoizedSerializedSize = -1;
   
+  @Override
   @SuppressWarnings("unchecked") // Guaranteed by runtime.
   public final Parser<MessageType> getParserForType() {
     return (Parser<MessageType>) dynamicMethod(MethodToInvoke.GET_PARSER);
   }
 
+  @Override
   @SuppressWarnings("unchecked") // Guaranteed by runtime.
   public final MessageType getDefaultInstanceForType() {
     return (MessageType) dynamicMethod(MethodToInvoke.GET_DEFAULT_INSTANCE);
   }
 
+  @Override
   @SuppressWarnings("unchecked") // Guaranteed by runtime.
   public final BuilderType newBuilderForType() {
     return (BuilderType) dynamicMethod(MethodToInvoke.NEW_BUILDER);
@@ -99,7 +103,65 @@ public abstract class GeneratedMessageLite<
     return MessageLiteToString.toString(this, super.toString());
   }
 
+  @SuppressWarnings("unchecked") // Guaranteed by runtime
+  @Override
+  public int hashCode() {
+    if (memoizedHashCode == 0) {
+      HashCodeVisitor visitor = new HashCodeVisitor();
+      visit(visitor, (MessageType) this);
+      memoizedHashCode = visitor.hashCode;
+    }
+    return memoizedHashCode;
+  }
+  
+  @SuppressWarnings("unchecked") // Guaranteed by runtime
+  int hashCode(HashCodeVisitor visitor) {
+    if (memoizedHashCode == 0) {
+      int inProgressHashCode = visitor.hashCode;
+      visitor.hashCode = 0;
+      visit(visitor, (MessageType) this);
+      memoizedHashCode = visitor.hashCode;
+      visitor.hashCode = inProgressHashCode;
+    }
+    return memoizedHashCode;
+  }
+  
+  @SuppressWarnings("unchecked") // Guaranteed by isInstance + runtime
+  @Override
+  public boolean equals(Object other) {
+    if (this == other) {
+      return true;
+    }
+    
+    if (!getDefaultInstanceForType().getClass().isInstance(other)) {
+      return false;
+    }
+    
+    try {
+      visit(EqualsVisitor.INSTANCE, (MessageType) other);
+    } catch (NotEqualsException e) {
+      return false;
+    }
+    return true;
+  }
+  
+  /**
+   * Same as {@link #equals(Object)} but throws {@code NotEqualsException}.
+   */
+  @SuppressWarnings("unchecked") // Guaranteed by isInstance + runtime
+  boolean equals(EqualsVisitor visitor, MessageLite other) {
+    if (this == other) {
+      return true;
+    }
+    
+    if (!getDefaultInstanceForType().getClass().isInstance(other)) {
+      return false;
+    }
 
+    visit(visitor, (MessageType) other);
+    return true;
+  }
+  
   // The general strategy for unknown fields is to use an UnknownFieldSetLite that is treated as
   // mutable during the parsing constructor and immutable after. This allows us to avoid
   // any unnecessary intermediary allocations while reducing the generated code size.
@@ -108,7 +170,7 @@ public abstract class GeneratedMessageLite<
    * Lazily initializes unknown fields.
    */
   private final void ensureUnknownFieldsInitialized() {
-    if (unknownFields == null) {
+    if (unknownFields == UnknownFieldSetLite.getDefaultInstance()) {
       unknownFields = UnknownFieldSetLite.newInstance();
     }
   }
@@ -147,18 +209,18 @@ public abstract class GeneratedMessageLite<
   /**
    * Called by subclasses to complete parsing. For use by generated code only.
    */
-  protected void doneParsing() {
-    if (unknownFields == null) {
-      unknownFields = UnknownFieldSetLite.getDefaultInstance();
-    } else {
-      unknownFields.makeImmutable();
-    }
+  protected void makeImmutable() {
+    dynamicMethod(MethodToInvoke.MAKE_IMMUTABLE);
+
+    unknownFields.makeImmutable();
   }
 
+  @Override
   public final boolean isInitialized() {
     return dynamicMethod(MethodToInvoke.IS_INITIALIZED, Boolean.TRUE) != null;
   }
 
+  @Override
   public final BuilderType toBuilder() {
     BuilderType builder = (BuilderType) dynamicMethod(MethodToInvoke.NEW_BUILDER);
     builder.mergeFrom((MessageType) this);
@@ -172,11 +234,14 @@ public abstract class GeneratedMessageLite<
    * For use by generated code only.
    */
   public static enum MethodToInvoke {
+    // Rely on/modify instance state
     IS_INITIALIZED,
-    PARSE_PARTIAL_FROM,
-    MERGE_FROM,
+    VISIT,
+    MERGE_FROM_STREAM,
     MAKE_IMMUTABLE,
-    NEW_INSTANCE,
+
+    // Rely on static state
+    NEW_MUTABLE_INSTANCE,
     NEW_BUILDER,
     GET_DEFAULT_INSTANCE,
     GET_PARSER;
@@ -188,17 +253,18 @@ public abstract class GeneratedMessageLite<
    * builders in the runtime. This method bundles those operations to reduce the generated methods
    * count.
    * <ul>
-   * <li>{@code PARSE_PARTIAL_FROM} is parameterized with an {@link CodedInputStream} and
+   * <li>{@code MERGE_FROM_STREAM} is parameterized with an {@link CodedInputStream} and
    * {@link ExtensionRegistryLite}. It consumes the input stream, parsing the contents into the
    * returned protocol buffer. If parsing throws an {@link InvalidProtocolBufferException}, the
-   * implementation wraps it in a RuntimeException
-   * <li>{@code NEW_INSTANCE} returns a new instance of the protocol buffer
+   * implementation wraps it in a RuntimeException.
+   * <li>{@code NEW_INSTANCE} returns a new instance of the protocol buffer that has not yet been
+   * made immutable. See {@code MAKE_IMMUTABLE}.
    * <li>{@code IS_INITIALIZED} is parameterized with a {@code Boolean} detailing whether to
    * memoize. It returns {@code null} for false and the default instance for true. We optionally
    * memoize to support the Builder case, where memoization is not desired.
    * <li>{@code NEW_BUILDER} returns a {@code BuilderType} instance.
-   * <li>{@code MERGE_FROM} is parameterized with a {@code MessageType} and merges the fields from
-   * that instance into this instance.
+   * <li>{@code VISIT} is parameterized with a {@code Visitor} and a {@code MessageType} and
+   * recursively iterates through the fields side by side between this and the instance.
    * <li>{@code MAKE_IMMUTABLE} sets all internal fields to an immutable state.
    * </ul>
    * This method, plus the implementation of the Builder, enables the Builder class to be proguarded
@@ -222,6 +288,11 @@ public abstract class GeneratedMessageLite<
     return dynamicMethod(method, null, null);
   }
 
+  void visit(Visitor visitor, MessageType other) {
+    dynamicMethod(MethodToInvoke.VISIT, visitor, other);
+    unknownFields = visitor.visitUnknownFields(unknownFields, other.unknownFields);
+  }
+  
   /**
    * Merge some unknown fields into the {@link UnknownFieldSetLite} for this
    * message.
@@ -236,7 +307,7 @@ public abstract class GeneratedMessageLite<
   public abstract static class Builder<
       MessageType extends GeneratedMessageLite<MessageType, BuilderType>,
       BuilderType extends Builder<MessageType, BuilderType>>
-          extends AbstractMessageLite.Builder<BuilderType> {
+          extends AbstractMessageLite.Builder<MessageType, BuilderType> {
 
     private final MessageType defaultInstance;
     protected MessageType instance;
@@ -244,7 +315,8 @@ public abstract class GeneratedMessageLite<
 
     protected Builder(MessageType defaultInstance) {
       this.defaultInstance = defaultInstance;
-      this.instance = (MessageType) defaultInstance.dynamicMethod(MethodToInvoke.NEW_INSTANCE);
+      this.instance =
+          (MessageType) defaultInstance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
       isBuilt = false;
     }
 
@@ -254,26 +326,27 @@ public abstract class GeneratedMessageLite<
      */
     protected void copyOnWrite() {
       if (isBuilt) {
-        MessageType newInstance = (MessageType) instance.dynamicMethod(MethodToInvoke.NEW_INSTANCE);
-        newInstance.dynamicMethod(MethodToInvoke.MERGE_FROM, instance);
+        MessageType newInstance =
+            (MessageType) instance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
+        newInstance.visit(MergeFromVisitor.INSTANCE, instance);
         instance = newInstance;
         isBuilt = false;
       }
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final boolean isInitialized() {
       return GeneratedMessageLite.isInitialized(instance, false /* shouldMemoize */);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final BuilderType clear() {
       // No need to copy on write since we're dropping the instance anyways.
-      instance = (MessageType) instance.dynamicMethod(MethodToInvoke.NEW_INSTANCE);
+      instance = (MessageType) instance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
       return (BuilderType) this;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public BuilderType clone() {
       BuilderType builder =
           (BuilderType) getDefaultInstanceForType().newBuilderForType();
@@ -281,20 +354,19 @@ public abstract class GeneratedMessageLite<
       return builder;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public MessageType buildPartial() {
       if (isBuilt) {
         return instance;
       }
       
-      instance.dynamicMethod(MethodToInvoke.MAKE_IMMUTABLE);
-      instance.unknownFields.makeImmutable();
+      instance.makeImmutable();
       
       isBuilt = true;
       return instance;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final MessageType build() {
       MessageType result = buildPartial();
       if (!result.isInitialized()) {
@@ -303,32 +375,36 @@ public abstract class GeneratedMessageLite<
       return result;
     }
     
+    @Override
+    protected BuilderType internalMergeFrom(MessageType message) {
+      return mergeFrom(message);
+    }
+    
     /** All subclasses implement this. */
     public BuilderType mergeFrom(MessageType message) {
       copyOnWrite();
-      instance.dynamicMethod(MethodToInvoke.MERGE_FROM, message);
+      instance.visit(MergeFromVisitor.INSTANCE, message);
       return (BuilderType) this;
     }
     
+    @Override
     public MessageType getDefaultInstanceForType() {
       return defaultInstance;
     }
     
+    @Override
     public BuilderType mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-        throws java.io.IOException {
-      MessageType parsedMessage = null;
+        throws IOException {
+      copyOnWrite();
       try {
-        parsedMessage = parsePartialFrom(
-            (MessageType) getDefaultInstanceForType(), input, extensionRegistry);
-      } catch (InvalidProtocolBufferException e) {
-        parsedMessage = (MessageType) e.getUnfinishedMessage();
-        throw e;
-      } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
+        instance.dynamicMethod(MethodToInvoke.MERGE_FROM_STREAM, input, extensionRegistry);
+      } catch (RuntimeException e) {
+        if (e.getCause() instanceof IOException) {
+          throw (IOException) e.getCause();
         }
+        throw e;
       }
       return (BuilderType) this;
     }
@@ -384,6 +460,12 @@ public abstract class GeneratedMessageLite<
       }
       extensions.mergeFrom(((ExtendableMessage) other).extensions);
     }
+
+    @Override
+    final void visit(Visitor visitor, MessageType other) {
+      super.visit(visitor, other);
+      extensions = visitor.visitExtensions(extensions, other.extensions);
+    }
     
     /**
      * Parse an unknown field or an extension. For use by generated code only.
@@ -521,9 +603,8 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Check if a singular extension is present. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public final <Type> boolean hasExtension(
-        final ExtensionLite<MessageType, Type> extension) {
+    @Override
+    public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extension) {
       GeneratedExtension<MessageType, Type> extensionLite =
           checkIsLite(extension);
       
@@ -532,7 +613,7 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Get the number of elements in a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final <Type> int getExtensionCount(
         final ExtensionLite<MessageType, List<Type>> extension) {
       GeneratedExtension<MessageType, List<Type>> extensionLite =
@@ -543,10 +624,9 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Get the value of an extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     @SuppressWarnings("unchecked")
-    public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, Type> extension) {
+    public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extension) {
       GeneratedExtension<MessageType, Type> extensionLite =
           checkIsLite(extension);
       
@@ -560,11 +640,10 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Get one element of a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     @SuppressWarnings("unchecked")
     public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, List<Type>> extension,
-        final int index) {
+        final ExtensionLite<MessageType, List<Type>> extension, final int index) {
       GeneratedExtension<MessageType, List<Type>> extensionLite =
           checkIsLite(extension);
 
@@ -579,8 +658,8 @@ public abstract class GeneratedMessageLite<
     }
 
     @Override
-    protected final void doneParsing() {
-      super.doneParsing();
+    protected final void makeImmutable() {
+      super.makeImmutable();
       
       extensions.makeImmutable();
     }
@@ -669,7 +748,7 @@ public abstract class GeneratedMessageLite<
       instance.extensions = extensions;
     }
 
-    // @Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     protected void copyOnWrite() {
       if (!isBuilt) {
         return;
@@ -679,7 +758,7 @@ public abstract class GeneratedMessageLite<
       instance.extensions = instance.extensions.clone();
     }
 
-    // @Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final MessageType buildPartial() {
       if (isBuilt) {
         return instance;
@@ -701,33 +780,30 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Check if a singular extension is present. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public final <Type> boolean hasExtension(
-        final ExtensionLite<MessageType, Type> extension) {
+    @Override
+    public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extension) {
       return instance.hasExtension(extension);
     }
 
     /** Get the number of elements in a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final <Type> int getExtensionCount(
         final ExtensionLite<MessageType, List<Type>> extension) {
       return instance.getExtensionCount(extension);
     }
 
     /** Get the value of an extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     @SuppressWarnings("unchecked")
-    public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, Type> extension) {
+    public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extension) {
       return instance.getExtension(extension);
     }
 
     /** Get one element of a repeated extension. */
+    @Override
     @SuppressWarnings("unchecked")
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
     public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, List<Type>> extension,
-        final int index) {
+        final ExtensionLite<MessageType, List<Type>> extension, final int index) {
       return instance.getExtension(extension, index);
     }
 
@@ -859,37 +935,44 @@ public abstract class GeneratedMessageLite<
     final boolean isRepeated;
     final boolean isPacked;
 
+    @Override
     public int getNumber() {
       return number;
     }
 
+    @Override
     public WireFormat.FieldType getLiteType() {
       return type;
     }
 
+    @Override
     public WireFormat.JavaType getLiteJavaType() {
       return type.getJavaType();
     }
 
+    @Override
     public boolean isRepeated() {
       return isRepeated;
     }
 
+    @Override
     public boolean isPacked() {
       return isPacked;
     }
 
+    @Override
     public Internal.EnumLiteMap<?> getEnumType() {
       return enumTypeMap;
     }
 
+    @Override
     @SuppressWarnings("unchecked")
-    public MessageLite.Builder internalMergeFrom(
-        MessageLite.Builder to, MessageLite from) {
+    public MessageLite.Builder internalMergeFrom(MessageLite.Builder to, MessageLite from) {
       return ((Builder) to).mergeFrom((GeneratedMessageLite) from);
     }
 
 
+    @Override
     public int compareTo(ExtensionDescriptor other) {
       return number - other.number;
     }
@@ -984,6 +1067,7 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Get the field number. */
+    @Override
     public int getNumber() {
       return descriptor.getNumber();
     }
@@ -993,6 +1077,7 @@ public abstract class GeneratedMessageLite<
      * If the extension is an embedded message or group, returns the default
      * instance of the message.
      */
+    @Override
     public MessageLite getMessageDefaultInstance() {
       return messageDefaultInstance;
     }
@@ -1047,14 +1132,17 @@ public abstract class GeneratedMessageLite<
       }
     }
 
+    @Override
     public FieldType getLiteType() {
       return descriptor.getLiteType();
     }
 
+    @Override
     public boolean isRepeated() {
       return descriptor.isRepeated;
     }
 
+    @Override
     public Type getDefaultValue() {
       return defaultValue;
     }
@@ -1139,112 +1227,72 @@ public abstract class GeneratedMessageLite<
   protected static final <T extends GeneratedMessageLite<T, ?>> boolean isInitialized(
       T message, boolean shouldMemoize) {
     return message.dynamicMethod(MethodToInvoke.IS_INITIALIZED, shouldMemoize) != null;
-  }
+  } 
   
   protected static final <T extends GeneratedMessageLite<T, ?>> void makeImmutable(T message) {
     message.dynamicMethod(MethodToInvoke.MAKE_IMMUTABLE);
   }
-  
-  protected static IntList newIntList() {
-    return new IntArrayList();
-  }
-  
-  protected static IntList newIntListWithCapacity(int capacity) {
-    return new IntArrayList(capacity);
-  }
-  
-  protected static IntList newIntList(List<Integer> toCopy) {
-    return new IntArrayList(toCopy);
-  }
-  
+
   protected static IntList emptyIntList() {
     return IntArrayList.emptyList();
   }
 
-  protected static LongList newLongList() {
-    return new LongArrayList();
+  protected static IntList mutableCopy(IntList list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
   }
 
-  protected static LongList newLongListWithCapacity(int capacity) {
-    return new LongArrayList(capacity);
-  }
-  
-  protected static LongList newLongList(List<Long> toCopy) {
-    return new LongArrayList(toCopy);
-  }
-  
   protected static LongList emptyLongList() {
     return LongArrayList.emptyList();
   }
   
-  protected static FloatList newFloatList() {
-    return new FloatArrayList();
+  protected static LongList mutableCopy(LongList list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
   }
-  
-  protected static FloatList newFloatListWithCapacity(int capacity) {
-    return new FloatArrayList(capacity);
-  }
-  
-  protected static FloatList newFloatList(List<Float> toCopy) {
-    return new FloatArrayList(toCopy);
-  }
-  
+
   protected static FloatList emptyFloatList() {
     return FloatArrayList.emptyList();
   }
   
-  protected static DoubleList newDoubleList() {
-    return new DoubleArrayList();
+  protected static FloatList mutableCopy(FloatList list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
   }
-  
-  protected static DoubleList newDoubleListWithCapacity(int capacity) {
-    return new DoubleArrayList(capacity);
-  }
-  
-  protected static DoubleList newDoubleList(List<Double> toCopy) {
-    return new DoubleArrayList(toCopy);
-  }
-  
+
   protected static DoubleList emptyDoubleList() {
     return DoubleArrayList.emptyList();
   }
   
-  protected static BooleanList newBooleanList() {
-    return new BooleanArrayList();
-  }
-  
-  protected static BooleanList newBooleanListWithCapacity(int capacity) {
-    return new BooleanArrayList(capacity);
+  protected static DoubleList mutableCopy(DoubleList list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
   }
-  
-  protected static BooleanList newBooleanList(List<Boolean> toCopy) {
-    return new BooleanArrayList(toCopy);
-  }
-  
+
   protected static BooleanList emptyBooleanList() {
     return BooleanArrayList.emptyList();
   }
   
-  protected static <E> ProtobufList<E> newProtobufList() {
-    return new ProtobufArrayList<E>();
-  }
-  
-  protected static <E> ProtobufList<E> newProtobufList(List<E> toCopy) {
-    return new ProtobufArrayList<E>(toCopy);
-  }
-  
-  protected static <E> ProtobufList<E> newProtobufListWithCapacity(int capacity) {
-    return new ProtobufArrayList<E>(capacity);
+  protected static BooleanList mutableCopy(BooleanList list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
   }
-  
+
   protected static <E> ProtobufList<E> emptyProtobufList() {
     return ProtobufArrayList.emptyList();
   }
-
-  protected static LazyStringArrayList emptyLazyStringArrayList() {
-    return LazyStringArrayList.emptyList();
-  }
   
+  protected static <E> ProtobufList<E> mutableCopy(ProtobufList<E> list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
+  }
+
   /**
    * A {@link Parser} implementation that delegates to the default instance.
    * <p>
@@ -1274,10 +1322,11 @@ public abstract class GeneratedMessageLite<
   static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
       T instance, CodedInputStream input, ExtensionRegistryLite extensionRegistry)
           throws InvalidProtocolBufferException {
-    T result;
+    @SuppressWarnings("unchecked") // Guaranteed by protoc
+    T result = (T) instance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
     try {
-      result = (T) instance.dynamicMethod(
-          MethodToInvoke.PARSE_PARTIAL_FROM, input, extensionRegistry);
+      result.dynamicMethod(MethodToInvoke.MERGE_FROM_STREAM, input, extensionRegistry);
+      result.makeImmutable();
     } catch (RuntimeException e) {
       if (e.getCause() instanceof InvalidProtocolBufferException) {
         throw (InvalidProtocolBufferException) e.getCause();
@@ -1454,4 +1503,740 @@ public abstract class GeneratedMessageLite<
     }
     return message;
   }
+
+  /**
+   * An abstract visitor that the generated code calls into that we use to implement various
+   * features. Fields that are not members of oneofs are always visited. Members of a oneof are only
+   * visited when they are the set oneof case value on the "other" proto. The visitOneofNotSet
+   * method is invoked if other's oneof case is not set.
+   */
+  protected interface Visitor {
+    boolean visitBoolean(boolean minePresent, boolean mine, boolean otherPresent, boolean other);
+    int visitInt(boolean minePresent, int mine, boolean otherPresent, int other);
+    double visitDouble(boolean minePresent, double mine, boolean otherPresent, double other);
+    float visitFloat(boolean minePresent, float mine, boolean otherPresent, float other);
+    long visitLong(boolean minePresent, long mine, boolean otherPresent, long other);
+    String visitString(boolean minePresent, String mine, boolean otherPresent, String other);
+    ByteString visitByteString(
+        boolean minePresent, ByteString mine, boolean otherPresent, ByteString other);
+
+    Object visitOneofBoolean(boolean minePresent, Object mine, Object other);
+    Object visitOneofInt(boolean minePresent, Object mine, Object other);
+    Object visitOneofDouble(boolean minePresent, Object mine, Object other);
+    Object visitOneofFloat(boolean minePresent, Object mine, Object other);
+    Object visitOneofLong(boolean minePresent, Object mine, Object other);
+    Object visitOneofString(boolean minePresent, Object mine, Object other);
+    Object visitOneofByteString(boolean minePresent, Object mine, Object other);
+    Object visitOneofLazyMessage(boolean minePresent, Object mine, Object other);
+    Object visitOneofMessage(boolean minePresent, Object mine, Object other);
+    void visitOneofNotSet(boolean minePresent);
+    
+    /**
+     * Message fields use null sentinals.
+     */
+    <T extends MessageLite> T visitMessage(T mine, T other);
+    LazyFieldLite visitLazyMessage(
+        boolean minePresent, LazyFieldLite mine, boolean otherPresent, LazyFieldLite other);
+
+    <T> ProtobufList<T> visitList(ProtobufList<T> mine, ProtobufList<T> other);
+    BooleanList visitBooleanList(BooleanList mine, BooleanList other);
+    IntList visitIntList(IntList mine, IntList other);
+    DoubleList visitDoubleList(DoubleList mine, DoubleList other);
+    FloatList visitFloatList(FloatList mine, FloatList other);
+    LongList visitLongList(LongList mine, LongList other);
+    FieldSet<ExtensionDescriptor> visitExtensions(
+        FieldSet<ExtensionDescriptor> mine, FieldSet<ExtensionDescriptor> other);
+    UnknownFieldSetLite visitUnknownFields(UnknownFieldSetLite mine, UnknownFieldSetLite other);
+    <K, V> MapFieldLite<K, V> visitMap(MapFieldLite<K, V> mine, MapFieldLite<K, V> other);
+  }
+
+  /**
+   * Implements equals. Throws a {@link NotEqualsException} when not equal.
+   */
+  static class EqualsVisitor implements Visitor {
+
+    static final class NotEqualsException extends RuntimeException {}
+
+    static final EqualsVisitor INSTANCE = new EqualsVisitor();
+
+    static final NotEqualsException NOT_EQUALS = new NotEqualsException();
+
+    private EqualsVisitor() {}
+
+    @Override
+    public boolean visitBoolean(
+        boolean minePresent, boolean mine, boolean otherPresent, boolean other) {
+      if (minePresent != otherPresent || mine != other) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public int visitInt(boolean minePresent, int mine, boolean otherPresent, int other) {
+      if (minePresent != otherPresent || mine != other) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public double visitDouble(
+        boolean minePresent, double mine, boolean otherPresent, double other) {
+      if (minePresent != otherPresent || mine != other) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public float visitFloat(boolean minePresent, float mine, boolean otherPresent, float other) {
+      if (minePresent != otherPresent || mine != other) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public long visitLong(boolean minePresent, long mine, boolean otherPresent, long other) {
+      if (minePresent != otherPresent || mine != other) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public String visitString(
+        boolean minePresent, String mine, boolean otherPresent, String other) {
+      if (minePresent != otherPresent || !mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public ByteString visitByteString(
+        boolean minePresent, ByteString mine, boolean otherPresent, ByteString other) {
+      if (minePresent != otherPresent || !mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofBoolean(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofInt(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofDouble(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofFloat(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofLong(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofString(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofByteString(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofLazyMessage(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+    
+    @Override
+    public Object visitOneofMessage(boolean minePresent, Object mine, Object other) {
+      if (minePresent && ((GeneratedMessageLite<?, ?>) mine).equals(this, (MessageLite) other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+    
+    @Override
+    public void visitOneofNotSet(boolean minePresent) {
+      if (minePresent) {
+        throw NOT_EQUALS;
+      }
+    }
+
+    @Override
+    public <T extends MessageLite> T visitMessage(T mine, T other) {
+      if (mine == null && other == null) {
+        return null;
+      }
+
+      if (mine == null || other == null) {
+        throw NOT_EQUALS;
+      }
+
+      ((GeneratedMessageLite<?, ?>) mine).equals(this, other);
+
+      return mine;
+    }
+    
+    @Override
+    public LazyFieldLite visitLazyMessage(
+        boolean minePresent, LazyFieldLite mine, boolean otherPresent, LazyFieldLite other) {
+      if (!minePresent && !otherPresent) {
+        return mine;
+      } else if (minePresent && otherPresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public <T> ProtobufList<T> visitList(ProtobufList<T> mine, ProtobufList<T> other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public BooleanList visitBooleanList(BooleanList mine, BooleanList other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public IntList visitIntList(IntList mine, IntList other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public DoubleList visitDoubleList(DoubleList mine, DoubleList other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public FloatList visitFloatList(FloatList mine, FloatList other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public LongList visitLongList(LongList mine, LongList other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public FieldSet<ExtensionDescriptor> visitExtensions(
+        FieldSet<ExtensionDescriptor> mine,
+        FieldSet<ExtensionDescriptor> other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public UnknownFieldSetLite visitUnknownFields(
+        UnknownFieldSetLite mine,
+        UnknownFieldSetLite other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public <K, V> MapFieldLite<K, V> visitMap(MapFieldLite<K, V> mine, MapFieldLite<K, V> other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+  }
+
+  /**
+   * Implements hashCode by accumulating state.
+   */
+  private static class HashCodeVisitor implements Visitor {
+
+    // The caller must ensure that the visitor is invoked parameterized with this and this such that
+    // other is this. This is required due to how oneof cases are handled. See the class comment
+    // on Visitor for more information.
+    
+    private int hashCode = 0;
+
+    @Override
+    public boolean visitBoolean(
+        boolean minePresent, boolean mine, boolean otherPresent, boolean other) {
+      hashCode = (53 * hashCode) + Internal.hashBoolean(mine);
+      return mine;
+    }
+
+    @Override
+    public int visitInt(boolean minePresent, int mine, boolean otherPresent, int other) {
+      hashCode = (53 * hashCode) + mine;
+      return mine;
+    }
+
+    @Override
+    public double visitDouble(
+        boolean minePresent, double mine, boolean otherPresent, double other) {
+      hashCode = (53 * hashCode) + Internal.hashLong(Double.doubleToLongBits(mine));
+      return mine;
+    }
+
+    @Override
+    public float visitFloat(boolean minePresent, float mine, boolean otherPresent, float other) {
+      hashCode = (53 * hashCode) + Float.floatToIntBits(mine);
+      return mine;
+    }
+
+    @Override
+    public long visitLong(boolean minePresent, long mine, boolean otherPresent, long other) {
+      hashCode = (53 * hashCode) + Internal.hashLong(mine);
+      return mine;
+    }
+
+    @Override
+    public String visitString(
+        boolean minePresent, String mine, boolean otherPresent, String other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public ByteString visitByteString(
+        boolean minePresent, ByteString mine, boolean otherPresent, ByteString other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofBoolean(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + Internal.hashBoolean(((Boolean) mine));
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofInt(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + (Integer) mine;
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofDouble(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + Internal.hashLong(Double.doubleToLongBits((Double) mine));
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofFloat(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + Float.floatToIntBits((Float) mine);
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofLong(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + Internal.hashLong((Long) mine);
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofString(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofByteString(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofLazyMessage(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+    
+    @Override
+    public Object visitOneofMessage(boolean minePresent, Object mine, Object other) {
+      return visitMessage((MessageLite) mine, (MessageLite) other);
+    }
+
+    @Override
+    public void visitOneofNotSet(boolean minePresent) {
+      if (minePresent) {
+        throw new IllegalStateException(); // Can't happen if other == this. 
+      }
+    }
+
+    @Override
+    public <T extends MessageLite> T visitMessage(T mine, T other) {
+      final int protoHash;
+      if (mine != null) {
+        if (mine instanceof GeneratedMessageLite) {
+          protoHash = ((GeneratedMessageLite) mine).hashCode(this);
+        } else {
+          protoHash = mine.hashCode();
+        }
+      } else {
+        protoHash = 37;
+      }
+      hashCode = (53 * hashCode) + protoHash;
+      return mine;
+    }
+
+    @Override
+    public LazyFieldLite visitLazyMessage(
+        boolean minePresent, LazyFieldLite mine, boolean otherPresent, LazyFieldLite other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public <T> ProtobufList<T> visitList(ProtobufList<T> mine, ProtobufList<T> other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public BooleanList visitBooleanList(BooleanList mine, BooleanList other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public IntList visitIntList(IntList mine, IntList other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public DoubleList visitDoubleList(DoubleList mine, DoubleList other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public FloatList visitFloatList(FloatList mine, FloatList other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public LongList visitLongList(LongList mine, LongList other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public FieldSet<ExtensionDescriptor> visitExtensions(
+        FieldSet<ExtensionDescriptor> mine,
+        FieldSet<ExtensionDescriptor> other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public UnknownFieldSetLite visitUnknownFields(
+        UnknownFieldSetLite mine,
+        UnknownFieldSetLite other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+    
+    @Override
+    public <K, V> MapFieldLite<K, V> visitMap(MapFieldLite<K, V> mine, MapFieldLite<K, V> other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+  }
+
+  /**
+   * Implements field merging semantics over the visitor interface.
+   */
+  protected static class MergeFromVisitor implements Visitor {
+
+    public static final MergeFromVisitor INSTANCE = new MergeFromVisitor();
+
+    private MergeFromVisitor() {}
+
+    @Override
+    public boolean visitBoolean(
+        boolean minePresent, boolean mine, boolean otherPresent, boolean other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public int visitInt(boolean minePresent, int mine, boolean otherPresent, int other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public double visitDouble(
+        boolean minePresent, double mine, boolean otherPresent, double other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public float visitFloat(boolean minePresent, float mine, boolean otherPresent, float other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public long visitLong(boolean minePresent, long mine, boolean otherPresent, long other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public String visitString(
+        boolean minePresent, String mine, boolean otherPresent, String other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public ByteString visitByteString(
+        boolean minePresent, ByteString mine, boolean otherPresent, ByteString other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public Object visitOneofBoolean(boolean minePresent, Object mine, Object other) {
+      return other;
+    }
+
+    @Override
+    public Object visitOneofInt(boolean minePresent, Object mine, Object other) {
+      return other;
+    }
+
+    @Override
+    public Object visitOneofDouble(boolean minePresent, Object mine, Object other) {
+      return other;      
+    }
+
+    @Override
+    public Object visitOneofFloat(boolean minePresent, Object mine, Object other) {
+      return other;
+    }
+
+    @Override
+    public Object visitOneofLong(boolean minePresent, Object mine, Object other) {
+      return other;      
+    }
+
+    @Override
+    public Object visitOneofString(boolean minePresent, Object mine, Object other) {
+      return other;      
+    }
+
+    @Override
+    public Object visitOneofByteString(boolean minePresent, Object mine, Object other) {
+      return other;      
+    }
+
+    @Override
+    public Object visitOneofLazyMessage(boolean minePresent, Object mine, Object other) {
+      if (minePresent) {
+        LazyFieldLite lazy = (LazyFieldLite) mine;
+        lazy.merge((LazyFieldLite) other);
+        return lazy;
+      }
+      return other;
+    }
+    
+    @Override
+    public Object visitOneofMessage(boolean minePresent, Object mine, Object other) {
+      if (minePresent) {
+        return visitMessage((MessageLite) mine, (MessageLite) other);
+      }
+      return other;
+    }
+    
+    @Override
+    public void visitOneofNotSet(boolean minePresent) {
+      return;
+    }
+
+    @SuppressWarnings("unchecked") // Guaranteed by runtime.
+    @Override
+    public <T extends MessageLite> T visitMessage(T mine, T other) {
+      if (mine != null && other != null) {
+        return (T) mine.toBuilder().mergeFrom(other).build();
+      }
+
+      return mine != null ? mine : other;
+    }
+
+    @Override
+    public LazyFieldLite visitLazyMessage(
+        boolean minePresent, LazyFieldLite mine, boolean otherPresent, LazyFieldLite other) {
+      // LazyFieldLite's are never null so we can just copy across. Necessary to avoid leakage
+      // from builder into immutable message.
+      // TODO(dweis): Change to null sentinels?
+      mine.merge(other);
+      return mine;
+    }
+
+    @Override
+    public <T> ProtobufList<T> visitList(ProtobufList<T> mine, ProtobufList<T> other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public BooleanList visitBooleanList(BooleanList mine, BooleanList other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public IntList visitIntList(IntList mine, IntList other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public DoubleList visitDoubleList(DoubleList mine, DoubleList other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public FloatList visitFloatList(FloatList mine, FloatList other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public LongList visitLongList(LongList mine, LongList other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public FieldSet<ExtensionDescriptor> visitExtensions(
+        FieldSet<ExtensionDescriptor> mine,
+        FieldSet<ExtensionDescriptor> other) {
+      if (mine.isImmutable()) {
+        mine = mine.clone();
+      }
+      mine.mergeFrom(other);
+      return mine;
+    }
+
+    @Override
+    public UnknownFieldSetLite visitUnknownFields(
+        UnknownFieldSetLite mine,
+        UnknownFieldSetLite other) {
+      return other == UnknownFieldSetLite.getDefaultInstance()
+          ? mine : UnknownFieldSetLite.mutableCopyOf(mine, other);
+    }
+    
+    @Override
+    public <K, V> MapFieldLite<K, V> visitMap(MapFieldLite<K, V> mine, MapFieldLite<K, V> other) {
+      mine.mergeFrom(other);
+      return mine;
+    }
+  }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/IntArrayList.java b/java/core/src/main/java/com/google/protobuf/IntArrayList.java
index f4e68ed8..6d6ece5a 100644
--- a/java/core/src/main/java/com/google/protobuf/IntArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/IntArrayList.java
@@ -34,7 +34,6 @@ import com.google.protobuf.Internal.IntList;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
 import java.util.RandomAccess;
 
 /**
@@ -44,8 +43,6 @@ import java.util.RandomAccess;
  */
 final class IntArrayList extends AbstractProtobufList<Integer> implements IntList, RandomAccess {
   
-  private static final int DEFAULT_CAPACITY = 10;
-  
   private static final IntArrayList EMPTY_LIST = new IntArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -70,32 +67,55 @@ final class IntArrayList extends AbstractProtobufList<Integer> implements IntLis
    * Constructs a new mutable {@code IntArrayList} with default capacity.
    */
   IntArrayList() {
-    this(DEFAULT_CAPACITY);
-  }
-
-  /**
-   * Constructs a new mutable {@code IntArrayList} with the provided capacity.
-   */
-  IntArrayList(int capacity) {
-    array = new int[capacity];
-    size = 0;
+    this(new int[DEFAULT_CAPACITY], 0);
   }
 
   /**
    * Constructs a new mutable {@code IntArrayList} containing the same elements as {@code other}.
    */
-  IntArrayList(List<Integer> other) {
-    if (other instanceof IntArrayList) {
-      IntArrayList list = (IntArrayList) other;
-      array = list.array.clone();
-      size = list.size;
-    } else {
-      size = other.size();
-      array = new int[size];
-      for (int i = 0; i < size; i++) {
-        array[i] = other.get(i);
+  private IntArrayList(int[] array, int size) {
+    this.array = array;
+    this.size = size;
+  }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof IntArrayList)) {
+      return super.equals(o);
+    }
+    IntArrayList other = (IntArrayList) o;
+    if (size != other.size) {
+      return false;
+    }
+    
+    final int[] arr = other.array;
+    for (int i = 0; i < size; i++) {
+      if (array[i] != arr[i]) {
+        return false;
       }
     }
+    
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = 1;
+    for (int i = 0; i < size; i++) {
+      result = (31 * result) + array[i];
+    }
+    return result;
+  }
+
+  @Override
+  public IntList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size) {
+      throw new IllegalArgumentException();
+    }
+    return new IntArrayList(Arrays.copyOf(array, capacity), size);
   }
   
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/Internal.java b/java/core/src/main/java/com/google/protobuf/Internal.java
index abf7ddd6..d1de375e 100644
--- a/java/core/src/main/java/com/google/protobuf/Internal.java
+++ b/java/core/src/main/java/com/google/protobuf/Internal.java
@@ -41,6 +41,7 @@ import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.RandomAccess;
 import java.util.Set;
 
 /**
@@ -457,10 +458,13 @@ public final class Internal {
     public static <T extends EnumLite> Converter<Integer, T> newEnumConverter(
         final EnumLiteMap<T> enumMap, final T unrecognizedValue) {
       return new Converter<Integer, T>() {
+        @Override
         public T doForward(Integer value) {
           T result = enumMap.findValueByNumber(value);
           return result == null ? unrecognizedValue : result;
         }
+
+        @Override
         public Integer doBackward(T value) {
           return value.getNumber();
         }
@@ -573,8 +577,10 @@ public final class Internal {
   /**
    * Extends {@link List} to add the capability to make the list immutable and inspect if it is
    * modifiable.
+   * <p>
+   * All implementations must support efficient random access.
    */
-  public static interface ProtobufList<E> extends List<E> {
+  public static interface ProtobufList<E> extends List<E>, RandomAccess {
 
     /**
      * Makes this list immutable. All subsequent modifications will throw an
@@ -586,6 +592,11 @@ public final class Internal {
      * Returns whether this list can be modified via the publicly accessible {@link List} methods.
      */
     boolean isModifiable();
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    ProtobufList<E> mutableCopyWithCapacity(int capacity);
   }
 
   /**
@@ -600,14 +611,20 @@ public final class Internal {
     int getInt(int index);
 
     /**
-     * Like {@link #add(Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #add(Integer)} but more efficient in that it doesn't box the element.
      */
     void addInt(int element);
 
     /**
-     * Like {@link #set(int, Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #set(int, Integer)} but more efficient in that it doesn't box the element.
      */
     int setInt(int index, int element);
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    @Override
+    IntList mutableCopyWithCapacity(int capacity);
   }
 
   /**
@@ -622,14 +639,20 @@ public final class Internal {
     boolean getBoolean(int index);
 
     /**
-     * Like {@link #add(Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #add(Boolean)} but more efficient in that it doesn't box the element.
      */
     void addBoolean(boolean element);
 
     /**
-     * Like {@link #set(int, Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #set(int, Boolean)} but more efficient in that it doesn't box the element.
      */
     boolean setBoolean(int index, boolean element);
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    @Override
+    BooleanList mutableCopyWithCapacity(int capacity);
   }
 
   /**
@@ -644,14 +667,20 @@ public final class Internal {
     long getLong(int index);
 
     /**
-     * Like {@link #add(Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #add(Long)} but more efficient in that it doesn't box the element.
      */
     void addLong(long element);
 
     /**
-     * Like {@link #set(int, Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #set(int, Long)} but more efficient in that it doesn't box the element.
      */
     long setLong(int index, long element);
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    @Override
+    LongList mutableCopyWithCapacity(int capacity);
   }
 
   /**
@@ -666,14 +695,20 @@ public final class Internal {
     double getDouble(int index);
 
     /**
-     * Like {@link #add(Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #add(Double)} but more efficient in that it doesn't box the element.
      */
     void addDouble(double element);
 
     /**
-     * Like {@link #set(int, Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #set(int, Double)} but more efficient in that it doesn't box the element.
      */
     double setDouble(int index, double element);
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    @Override
+    DoubleList mutableCopyWithCapacity(int capacity);
   }
 
   /**
@@ -688,13 +723,19 @@ public final class Internal {
     float getFloat(int index);
 
     /**
-     * Like {@link #add(Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #add(Float)} but more efficient in that it doesn't box the element.
      */
     void addFloat(float element);
 
     /**
-     * Like {@link #set(int, Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #set(int, Float)} but more efficient in that it doesn't box the element.
      */
     float setFloat(int index, float element);
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    @Override
+    FloatList mutableCopyWithCapacity(int capacity);
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/LazyField.java b/java/core/src/main/java/com/google/protobuf/LazyField.java
index 3da8b900..98e13ca1 100644
--- a/java/core/src/main/java/com/google/protobuf/LazyField.java
+++ b/java/core/src/main/java/com/google/protobuf/LazyField.java
@@ -95,12 +95,12 @@ public class LazyField extends LazyFieldLite {
       this.entry = entry;
     }
 
-    // @Override
+    @Override
     public K getKey() {
       return entry.getKey();
     }
 
-    // @Override
+    @Override
     public Object getValue() {
       LazyField field = entry.getValue();
       if (field == null) {
@@ -113,7 +113,7 @@ public class LazyField extends LazyFieldLite {
       return entry.getValue();
     }
 
-    // @Override
+    @Override
     public Object setValue(Object value) {
       if (!(value instanceof MessageLite)) {
         throw new IllegalArgumentException(
@@ -131,13 +131,13 @@ public class LazyField extends LazyFieldLite {
       this.iterator = iterator;
     }
 
-    // @Override
+    @Override
     public boolean hasNext() {
       return iterator.hasNext();
     }
 
+    @Override
     @SuppressWarnings("unchecked")
-    // @Override
     public Entry<K, Object> next() {
       Entry<K, ?> entry = iterator.next();
       if (entry.getValue() instanceof LazyField) {
@@ -146,7 +146,7 @@ public class LazyField extends LazyFieldLite {
       return (Entry<K, Object>) entry;
     }
 
-    // @Override
+    @Override
     public void remove() {
       iterator.remove();
     }
diff --git a/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java b/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java
index 016ec20d..2febaace 100644
--- a/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java
+++ b/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java
@@ -135,6 +135,43 @@ public class LazyFieldLite {
     return lf;
   }
 
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    
+    if (!(o instanceof LazyFieldLite)) {
+      return false;
+    }
+
+    LazyFieldLite other = (LazyFieldLite) o;
+    
+    // Lazy fields do not work well with equals... If both are delayedBytes, we do not have a
+    // mechanism to deserialize them so we rely on bytes equality. Otherwise we coerce into an
+    // actual message (if necessary) and call equals on the message itself. This implies that two
+    // messages can by unequal but then be turned equal simply be invoking a getter on a lazy field.
+    MessageLite value1 = value;
+    MessageLite value2 = other.value;
+    if (value1 == null && value2 == null) {
+      return toByteString().equals(other.toByteString());
+    } else if (value1 != null && value2 != null) {
+      return value1.equals(value2);
+    } else if (value1 != null) {
+      return value1.equals(other.getValue(value1.getDefaultInstanceForType()));
+    } else {
+      return getValue(value2.getDefaultInstanceForType()).equals(value2);
+    }
+  }
+  
+  @Override
+  public int hashCode() {
+    // We can't provide a memoizable hash code for lazy fields. The byte strings may have different
+    // hash codes but evaluate to equivalent messages. And we have no facility for constructing
+    // a message here if we were not already holding a value.
+    return 1;
+  }
+  
   /**
    * Determines whether this LazyFieldLite instance represents the default instance of this type.
    */
@@ -340,6 +377,8 @@ public class LazyFieldLite {
    * parsed. Be careful when using this method.
    */
   public int getSerializedSize() {
+    // We *must* return delayed bytes size if it was ever set because the dependent messages may
+    // have memoized serialized size based off of it.
     if (memoizedBytes != null) {
       return memoizedBytes.size();
     } else if (delayedBytes != null) {
@@ -358,6 +397,8 @@ public class LazyFieldLite {
     if (memoizedBytes != null) {
       return memoizedBytes;
     }
+    // We *must* return delayed bytes if it was set because the dependent messages may have
+    // memoized serialized size based off of it.
     if (delayedBytes != null) {
       return delayedBytes;
     }
diff --git a/java/core/src/main/java/com/google/protobuf/LazyStringArrayList.java b/java/core/src/main/java/com/google/protobuf/LazyStringArrayList.java
index 68c430cf..d474c51e 100644
--- a/java/core/src/main/java/com/google/protobuf/LazyStringArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/LazyStringArrayList.java
@@ -64,7 +64,7 @@ import java.util.RandomAccess;
  */
 public class LazyStringArrayList extends AbstractProtobufList<String>
     implements LazyStringList, RandomAccess {
-  
+
   private static final LazyStringArrayList EMPTY_LIST = new LazyStringArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -80,11 +80,11 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
   private final List<Object> list;
 
   public LazyStringArrayList() {
-    list = new ArrayList<Object>();
+    this(DEFAULT_CAPACITY);
   }
 
   public LazyStringArrayList(int intialCapacity) {
-    list = new ArrayList<Object>(intialCapacity);
+    this(new ArrayList<Object>(intialCapacity));
   }
 
   public LazyStringArrayList(LazyStringList from) {
@@ -93,7 +93,21 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
   }
 
   public LazyStringArrayList(List<String> from) {
-    list = new ArrayList<Object>(from);
+    this(new ArrayList<Object>(from));
+  }
+  
+  private LazyStringArrayList(ArrayList<Object> list) {
+    this.list = list;
+  }
+
+  @Override
+  public LazyStringArrayList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size()) {
+      throw new IllegalArgumentException();
+    }
+    ArrayList<Object> newList = new ArrayList<Object>(capacity);
+    newList.addAll(list);
+    return new LazyStringArrayList(newList);
   }
 
   @Override
@@ -170,7 +184,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return ret;
   }
 
-  // @Override
+  @Override
   public boolean addAllByteString(Collection<? extends ByteString> values) {
     ensureIsMutable();
     boolean ret = list.addAll(values);
@@ -178,7 +192,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return ret;
   }
 
-  // @Override
+  @Override
   public boolean addAllByteArray(Collection<byte[]> c) {
     ensureIsMutable();
     boolean ret = list.addAll(c);
@@ -201,14 +215,14 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     modCount++;
   }
 
-  // @Override
+  @Override
   public void add(ByteString element) {
     ensureIsMutable();
     list.add(element);
     modCount++;
   }
   
-  // @Override
+  @Override
   public void add(byte[] element) {
     ensureIsMutable();
     list.add(element);
@@ -220,7 +234,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return list.get(index);
   }
   
-  // @Override
+  @Override
   public ByteString getByteString(int index) {
     Object o = list.get(index);
     ByteString b = asByteString(o);
@@ -230,7 +244,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return b;
   }
   
-  // @Override
+  @Override
   public byte[] getByteArray(int index) {
     Object o = list.get(index);
     byte[] b = asByteArray(o);
@@ -240,7 +254,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return b;
   }
 
-  // @Override
+  @Override
   public void set(int index, ByteString s) {
     setAndReturn(index, s);
   }
@@ -250,7 +264,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return list.set(index, s);
   }
 
-  // @Override
+  @Override
   public void set(int index, byte[] s) {
     setAndReturn(index, s);
   }
@@ -290,12 +304,12 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     }
   }
 
-  // @Override
+  @Override
   public List<?> getUnderlyingElements() {
     return Collections.unmodifiableList(list);
   }
 
-  // @Override
+  @Override
   public void mergeFrom(LazyStringList other) {
     ensureIsMutable();
     for (Object o : other.getUnderlyingElements()) {
@@ -349,7 +363,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     }
   }
   
-  // @Override
+  @Override
   public List<byte[]> asByteArrayList() {
     return new ByteArrayListView(this);
   }
@@ -393,12 +407,12 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     }
   }
 
-  // @Override
+  @Override
   public List<ByteString> asByteStringList() {
     return new ByteStringListView(this);
   }
 
-  // @Override
+  @Override
   public LazyStringList getUnmodifiableView() {
     if (isModifiable()) {
       return new UnmodifiableLazyStringList(this);
diff --git a/java/core/src/main/java/com/google/protobuf/LongArrayList.java b/java/core/src/main/java/com/google/protobuf/LongArrayList.java
index ebe62029..bc4475d1 100644
--- a/java/core/src/main/java/com/google/protobuf/LongArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/LongArrayList.java
@@ -34,7 +34,6 @@ import com.google.protobuf.Internal.LongList;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
 import java.util.RandomAccess;
 
 /**
@@ -44,8 +43,6 @@ import java.util.RandomAccess;
  */
 final class LongArrayList extends AbstractProtobufList<Long> implements LongList, RandomAccess {
   
-  private static final int DEFAULT_CAPACITY = 10;
-  
   private static final LongArrayList EMPTY_LIST = new LongArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -70,32 +67,55 @@ final class LongArrayList extends AbstractProtobufList<Long> implements LongList
    * Constructs a new mutable {@code LongArrayList} with default capacity.
    */
   LongArrayList() {
-    this(DEFAULT_CAPACITY);
-  }
-
-  /**
-   * Constructs a new mutable {@code LongArrayList} with the provided capacity.
-   */
-  LongArrayList(int capacity) {
-    array = new long[capacity];
-    size = 0;
+    this(new long[DEFAULT_CAPACITY], 0);
   }
 
   /**
    * Constructs a new mutable {@code LongArrayList} containing the same elements as {@code other}.
    */
-  LongArrayList(List<Long> other) {
-    if (other instanceof LongArrayList) {
-      LongArrayList list = (LongArrayList) other;
-      array = list.array.clone();
-      size = list.size;
-    } else {
-      size = other.size();
-      array = new long[size];
-      for (int i = 0; i < size; i++) {
-        array[i] = other.get(i);
+  private LongArrayList(long[] array, int size) {
+    this.array = array;
+    this.size = size;
+  }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof IntArrayList)) {
+      return super.equals(o);
+    }
+    LongArrayList other = (LongArrayList) o;
+    if (size != other.size) {
+      return false;
+    }
+    
+    final long[] arr = other.array;
+    for (int i = 0; i < size; i++) {
+      if (array[i] != arr[i]) {
+        return false;
       }
     }
+    
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = 1;
+    for (int i = 0; i < size; i++) {
+      result = (31 * result) + Internal.hashLong(array[i]);
+    }
+    return result;
+  }
+
+  @Override
+  public LongList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size) {
+      throw new IllegalArgumentException();
+    }
+    return new LongArrayList(Arrays.copyOf(array, capacity), size);
   }
   
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/MapEntryLite.java b/java/core/src/main/java/com/google/protobuf/MapEntryLite.java
index bcffa946..12c64abb 100644
--- a/java/core/src/main/java/com/google/protobuf/MapEntryLite.java
+++ b/java/core/src/main/java/com/google/protobuf/MapEntryLite.java
@@ -41,7 +41,8 @@ import java.io.IOException;
  * 
  * Protobuf internal. Users shouldn't use.
  */
-public class MapEntryLite<K, V> extends AbstractMessageLite {
+public class MapEntryLite<K, V>
+    extends AbstractMessageLite<MapEntryLite<K, V>, MapEntryLite.Builder<K, V>> {
   private static class Metadata<K, V> {
     public final MapEntryLite<K, V> defaultInstance;
     public final WireFormat.FieldType keyType;
@@ -233,7 +234,7 @@ public class MapEntryLite<K, V> extends AbstractMessageLite {
    * Builder used to create {@link MapEntryLite} messages.
    */
   public static class Builder<K, V>
-      extends AbstractMessageLite.Builder<Builder<K, V>> {
+      extends AbstractMessageLite.Builder<MapEntryLite<K, V>, Builder<K, V>> {
     private final Metadata<K, V> metadata;
     private K key;
     private V value;
@@ -327,5 +328,10 @@ public class MapEntryLite<K, V> extends AbstractMessageLite {
       this.value = entry.value;
       return this;
     }
+
+    @Override
+    protected Builder<K, V> internalMergeFrom(MapEntryLite<K, V> message) {
+      throw new UnsupportedOperationException();
+    }
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/MapField.java b/java/core/src/main/java/com/google/protobuf/MapField.java
index b290993c..907f0f71 100644
--- a/java/core/src/main/java/com/google/protobuf/MapField.java
+++ b/java/core/src/main/java/com/google/protobuf/MapField.java
@@ -93,15 +93,18 @@ public class MapField<K, V> implements MutabilityOracle {
       this.defaultEntry = defaultEntry;
     }
     
+    @Override
     public Message convertKeyAndValueToMessage(K key, V value) {
       return defaultEntry.newBuilderForType().setKey(key).setValue(value).buildPartial();
     }
     
+    @Override
     public void convertMessageToKeyAndValue(Message message, Map<K, V> map) {
       MapEntry<K, V> entry = (MapEntry<K, V>) message;
       map.put(entry.getKey(), entry.getValue());
     }
 
+    @Override
     public Message getMessageDefaultInstance() {
       return defaultEntry;
     }
diff --git a/java/core/src/main/java/com/google/protobuf/Message.java b/java/core/src/main/java/com/google/protobuf/Message.java
index 9516d71f..94590fb9 100644
--- a/java/core/src/main/java/com/google/protobuf/Message.java
+++ b/java/core/src/main/java/com/google/protobuf/Message.java
@@ -51,6 +51,7 @@ import java.util.Map;
 public interface Message extends MessageLite, MessageOrBuilder {
 
   // (From MessageLite, re-declared here only for return type covariance.)
+  @Override
   Parser<? extends Message> getParserForType();
 
 
@@ -97,7 +98,10 @@ public interface Message extends MessageLite, MessageOrBuilder {
   // Builders
 
   // (From MessageLite, re-declared here only for return type covariance.)
+  @Override
   Builder newBuilderForType();
+
+  @Override
   Builder toBuilder();
 
   /**
@@ -106,6 +110,7 @@ public interface Message extends MessageLite, MessageOrBuilder {
   interface Builder extends MessageLite.Builder, MessageOrBuilder {
     // (From MessageLite.Builder, re-declared here only for return type
     // covariance.)
+    @Override
     Builder clear();
 
     /**
@@ -131,18 +136,27 @@ public interface Message extends MessageLite, MessageOrBuilder {
 
     // (From MessageLite.Builder, re-declared here only for return type
     // covariance.)
+    @Override
     Message build();
+
+    @Override
     Message buildPartial();
+
+    @Override
     Builder clone();
+
+    @Override
     Builder mergeFrom(CodedInputStream input) throws IOException;
-    Builder mergeFrom(CodedInputStream input,
-                      ExtensionRegistryLite extensionRegistry)
-                      throws IOException;
+
+    @Override
+    Builder mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException;
 
     /**
      * Get the message's type's descriptor.
      * See {@link Message#getDescriptorForType()}.
      */
+    @Override
     Descriptors.Descriptor getDescriptorForType();
 
     /**
@@ -240,27 +254,39 @@ public interface Message extends MessageLite, MessageOrBuilder {
 
     // (From MessageLite.Builder, re-declared here only for return type
     // covariance.)
+    @Override
     Builder mergeFrom(ByteString data) throws InvalidProtocolBufferException;
-    Builder mergeFrom(ByteString data,
-                      ExtensionRegistryLite extensionRegistry)
-                      throws InvalidProtocolBufferException;
+
+    @Override
+    Builder mergeFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException;
+
+    @Override
     Builder mergeFrom(byte[] data) throws InvalidProtocolBufferException;
-    Builder mergeFrom(byte[] data, int off, int len)
-                      throws InvalidProtocolBufferException;
-    Builder mergeFrom(byte[] data,
-                      ExtensionRegistryLite extensionRegistry)
-                      throws InvalidProtocolBufferException;
-    Builder mergeFrom(byte[] data, int off, int len,
-                      ExtensionRegistryLite extensionRegistry)
-                      throws InvalidProtocolBufferException;
+
+    @Override
+    Builder mergeFrom(byte[] data, int off, int len) throws InvalidProtocolBufferException;
+
+    @Override
+    Builder mergeFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException;
+
+    @Override
+    Builder mergeFrom(byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException;
+
+    @Override
     Builder mergeFrom(InputStream input) throws IOException;
-    Builder mergeFrom(InputStream input,
-                      ExtensionRegistryLite extensionRegistry)
-                      throws IOException;
-    boolean mergeDelimitedFrom(InputStream input)
-                               throws IOException;
-    boolean mergeDelimitedFrom(InputStream input,
-                               ExtensionRegistryLite extensionRegistry)
-                               throws IOException;
+
+    @Override
+    Builder mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException;
+
+    @Override
+    boolean mergeDelimitedFrom(InputStream input) throws IOException;
+
+    @Override
+    boolean mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException;
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/MessageLite.java b/java/core/src/main/java/com/google/protobuf/MessageLite.java
index 798b7943..88f531df 100644
--- a/java/core/src/main/java/com/google/protobuf/MessageLite.java
+++ b/java/core/src/main/java/com/google/protobuf/MessageLite.java
@@ -295,6 +295,27 @@ public interface MessageLite extends MessageLiteOrBuilder {
     Builder mergeFrom(InputStream input,
                       ExtensionRegistryLite extensionRegistry)
                       throws IOException;
+    
+    /**
+     * Merge {@code other} into the message being built.  {@code other} must
+     * have the exact same type as {@code this} (i.e.
+     * {@code getClass().equals(getDefaultInstanceForType().getClass())}).
+     *
+     * Merging occurs as follows.  For each field:<br>
+     * * For singular primitive fields, if the field is set in {@code other},
+     *   then {@code other}'s value overwrites the value in this message.<br>
+     * * For singular message fields, if the field is set in {@code other},
+     *   it is merged into the corresponding sub-message of this message
+     *   using the same merging rules.<br>
+     * * For repeated fields, the elements in {@code other} are concatenated
+     *   with the elements in this message.
+     * * For oneof groups, if the other message has one of the fields set,
+     *   the group of this message is cleared and replaced by the field
+     *   of the other message, so that the oneof constraint is preserved.
+     *
+     * This is equivalent to the {@code Message::MergeFrom} method in C++.
+     */
+    Builder mergeFrom(MessageLite other);
 
     /**
      * Like {@link #mergeFrom(InputStream)}, but does not read until EOF.
diff --git a/java/core/src/main/java/com/google/protobuf/MessageLiteToString.java b/java/core/src/main/java/com/google/protobuf/MessageLiteToString.java
index 2a6e0e30..43847651 100644
--- a/java/core/src/main/java/com/google/protobuf/MessageLiteToString.java
+++ b/java/core/src/main/java/com/google/protobuf/MessageLiteToString.java
@@ -30,23 +30,24 @@
 
 package com.google.protobuf;
 
-import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
+import java.util.TreeSet;
 
 /**
  * Helps generate {@link String} representations of {@link MessageLite} protos.
  */
+// TODO(dweis): Fix map fields.
 final class MessageLiteToString {
-  /**
-   * Suffix for *_FIELD_NUMBER fields. This is used to reflectively detect proto fields that should
-   * be toString()ed.
-   */
-  private static final String FIELD_NUMBER_NAME_SUFFIX = "_FIELD_NUMBER";
 
+  private static final String LIST_SUFFIX = "List";
+  private static final String BUILDER_LIST_SUFFIX = "OrBuilderList";
+  private static final String BYTES_SUFFIX = "Bytes";
+  
   /**
    * Returns a {@link String} representation of the {@link MessageLite} object.  The first line of
    * the {@code String} representation representation includes a comment string to uniquely identify
@@ -73,52 +74,70 @@ final class MessageLiteToString {
     // Build a map of method name to method. We're looking for methods like getFoo(), hasFoo(), and
     // getFooList() which might be useful for building an object's string representation.
     Map<String, Method> nameToNoArgMethod = new HashMap<String, Method>();
+    Map<String, Method> nameToMethod = new HashMap<String, Method>();
+    Set<String> getters = new TreeSet<String>();
     for (Method method : messageLite.getClass().getDeclaredMethods()) {
+      nameToMethod.put(method.getName(), method);
       if (method.getParameterTypes().length == 0) {
         nameToNoArgMethod.put(method.getName(), method);
+
+        if (method.getName().startsWith("get")) {
+          getters.add(method.getName());
+        }
       }
     }
 
-    for (Field field : messageLite.getClass().getDeclaredFields()) {
-      String fieldName = field.getName();
-      // Skip all fields that aren't in a format like "FOO_BAR_FIELD_NUMBER"
-      if (!fieldName.endsWith(FIELD_NUMBER_NAME_SUFFIX)) {
-        continue;
+    for (String getter : getters) {
+      String suffix = getter.replaceFirst("get", "");
+      if (suffix.endsWith(LIST_SUFFIX) && !suffix.endsWith(BUILDER_LIST_SUFFIX)) {
+        String camelCase = suffix.substring(0, 1).toLowerCase()
+            + suffix.substring(1, suffix.length() - LIST_SUFFIX.length());
+        // Try to reflectively get the value and toString() the field as if it were repeated. This
+        // only works if the method names have not be proguarded out or renamed.
+        Method listMethod = nameToNoArgMethod.get("get" + suffix);
+        if (listMethod != null) {
+          printField(
+              buffer,
+              indent,
+              camelCaseToSnakeCase(camelCase),
+              GeneratedMessageLite.invokeOrDie(listMethod, messageLite));
+          continue;
+        }
       }
 
-      // For "FOO_BAR_FIELD_NUMBER" his would be "FOO_BAR"
-      String upperUnderscore =
-          fieldName.substring(0, fieldName.length() - FIELD_NUMBER_NAME_SUFFIX.length());
-
-      // For "FOO_BAR_FIELD_NUMBER" his would be "FooBar"
-      String upperCamelCaseName = upperUnderscoreToUpperCamel(upperUnderscore);
+      Method setter = nameToMethod.get("set" + suffix);
+      if (setter == null) {
+        continue;
+      }
+      if (suffix.endsWith(BYTES_SUFFIX)
+          && nameToNoArgMethod.containsKey(
+              "get" + suffix.substring(0, suffix.length() - "Bytes".length()))) {
+        // Heuristic to skip bytes based accessors for string fields.
+        continue;
+      }
+      
+      String camelCase = suffix.substring(0, 1).toLowerCase() + suffix.substring(1);
 
       // Try to reflectively get the value and toString() the field as if it were optional. This
       // only works if the method names have not be proguarded out or renamed.
-      Method getMethod = nameToNoArgMethod.get("get" + upperCamelCaseName);
-      Method hasMethod = nameToNoArgMethod.get("has" + upperCamelCaseName);
-      if (getMethod != null && hasMethod != null) {
-        if ((Boolean) GeneratedMessageLite.invokeOrDie(hasMethod, messageLite)) {
+      Method getMethod = nameToNoArgMethod.get("get" + suffix);
+      Method hasMethod = nameToNoArgMethod.get("has" + suffix);
+      // TODO(dweis): Fix proto3 semantics.
+      if (getMethod != null) {
+        Object value = GeneratedMessageLite.invokeOrDie(getMethod, messageLite);
+        final boolean hasValue = hasMethod == null
+            ? !isDefaultValue(value)
+            : (Boolean) GeneratedMessageLite.invokeOrDie(hasMethod, messageLite);
+         // TODO(dweis): This doesn't stop printing oneof case twice: value and enum style.
+        if (hasValue) {
           printField(
               buffer,
               indent,
-              upperUnderscore.toLowerCase(),
-              GeneratedMessageLite.invokeOrDie(getMethod, messageLite));
+              camelCaseToSnakeCase(camelCase),
+              value);
         }
         continue;
       }
-
-      // Try to reflectively get the value and toString() the field as if it were repeated. This
-      // only works if the method names have not be proguarded out or renamed.
-      Method listMethod = nameToNoArgMethod.get("get" + upperCamelCaseName + "List");
-      if (listMethod != null) {
-        printField(
-            buffer,
-            indent,
-            upperUnderscore.toLowerCase(),
-            GeneratedMessageLite.invokeOrDie(listMethod, messageLite));
-        continue;
-      }
     }
 
     if (messageLite instanceof GeneratedMessageLite.ExtendableMessage) {
@@ -130,10 +149,39 @@ final class MessageLiteToString {
       }
     }
 
-    if (((GeneratedMessageLite) messageLite).unknownFields != null) {
-      ((GeneratedMessageLite) messageLite).unknownFields.printWithIndent(buffer, indent);
+    if (((GeneratedMessageLite<?, ?>) messageLite).unknownFields != null) {
+      ((GeneratedMessageLite<?, ?>) messageLite).unknownFields.printWithIndent(buffer, indent);
     }
   }
+  
+  private static boolean isDefaultValue(Object o) {
+    if (o instanceof Boolean) {
+      return !((Boolean) o);
+    }
+    if (o instanceof Integer) {
+      return ((Integer) o) == 0;
+    }
+    if (o instanceof Float) {
+      return ((Float) o) == 0f;
+    }
+    if (o instanceof Double) {
+      return ((Double) o) == 0d;
+    }
+    if (o instanceof String) {
+      return o.equals("");
+    }
+    if (o instanceof ByteString) {
+      return o.equals(ByteString.EMPTY);
+    }
+    if (o instanceof MessageLite) { // Can happen in oneofs.
+      return o == ((MessageLite) o).getDefaultInstanceForType();
+    }
+    if (o instanceof java.lang.Enum<?>) { // Catches oneof enums.
+      return ((java.lang.Enum<?>) o).ordinal() == 0;
+    }
+    
+    return false;
+  }
 
   /**
    * Formats a text proto field.
@@ -166,7 +214,7 @@ final class MessageLiteToString {
       buffer.append(": \"").append(TextFormatEscaper.escapeBytes((ByteString) object)).append('"');
     } else if (object instanceof GeneratedMessageLite) {
       buffer.append(" {");
-      reflectivePrintWithIndent((GeneratedMessageLite) object, buffer, indent + 2);
+      reflectivePrintWithIndent((GeneratedMessageLite<?, ?>) object, buffer, indent + 2);
       buffer.append("\n");
       for (int i = 0; i < indent; i++) {
         buffer.append(' ');
@@ -176,25 +224,16 @@ final class MessageLiteToString {
       buffer.append(": ").append(object.toString());
     }
   }
-
-  /**
-   * A Guava-less implementation of:
-   * {@code CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.UPPER_CAMEL, upperUnderscore)}
-   */
-  private static String upperUnderscoreToUpperCamel(String upperUnderscore) {
-    String upperCamelCaseName = "";
-    boolean nextCharacterShouldBeUpper = true;
-    for (int i = 0; i < upperUnderscore.length(); i++) {
-      char ch = upperUnderscore.charAt(i);
-      if (ch == '_') {
-        nextCharacterShouldBeUpper = true;
-      } else if (nextCharacterShouldBeUpper){
-        upperCamelCaseName += Character.toUpperCase(ch);
-        nextCharacterShouldBeUpper = false;
-      } else {
-        upperCamelCaseName += Character.toLowerCase(ch);
+  
+  private static final String camelCaseToSnakeCase(String camelCase) {
+    StringBuilder builder = new StringBuilder();
+    for (int i = 0; i < camelCase.length(); i++) {
+      char ch = camelCase.charAt(i);
+      if (Character.isUpperCase(ch)) {
+        builder.append("_");
       }
+      builder.append(Character.toLowerCase(ch));
     }
-    return upperCamelCaseName;
+    return builder.toString();
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/MessageOrBuilder.java b/java/core/src/main/java/com/google/protobuf/MessageOrBuilder.java
index f0fc4859..5e7d7821 100644
--- a/java/core/src/main/java/com/google/protobuf/MessageOrBuilder.java
+++ b/java/core/src/main/java/com/google/protobuf/MessageOrBuilder.java
@@ -42,7 +42,7 @@ import java.util.Map;
 public interface MessageOrBuilder extends MessageLiteOrBuilder {
 
   // (From MessageLite, re-declared here only for return type covariance.)
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   Message getDefaultInstanceForType();
 
   /**
diff --git a/java/core/src/main/java/com/google/protobuf/MessageReflection.java b/java/core/src/main/java/com/google/protobuf/MessageReflection.java
index de4bfd3e..7b791d9e 100644
--- a/java/core/src/main/java/com/google/protobuf/MessageReflection.java
+++ b/java/core/src/main/java/com/google/protobuf/MessageReflection.java
@@ -364,12 +364,14 @@ class MessageReflection {
      * Finishes the merge and returns the underlying object.
      */
     Object finish();
+    
   }
 
   static class BuilderAdapter implements MergeTarget {
 
     private final Message.Builder builder;
 
+    @Override
     public Descriptors.Descriptor getDescriptorForType() {
       return builder.getDescriptorForType();
     }
@@ -378,6 +380,7 @@ class MessageReflection {
       this.builder = builder;
     }
 
+    @Override
     public Object getField(Descriptors.FieldDescriptor field) {
       return builder.getField(field);
     }
@@ -387,25 +390,27 @@ class MessageReflection {
       return builder.hasField(field);
     }
 
-    public MergeTarget setField(Descriptors.FieldDescriptor field,
-        Object value) {
+    @Override
+    public MergeTarget setField(Descriptors.FieldDescriptor field, Object value) {
       builder.setField(field, value);
       return this;
     }
 
+    @Override
     public MergeTarget clearField(Descriptors.FieldDescriptor field) {
       builder.clearField(field);
       return this;
     }
 
+    @Override
     public MergeTarget setRepeatedField(
         Descriptors.FieldDescriptor field, int index, Object value) {
       builder.setRepeatedField(field, index, value);
       return this;
     }
 
-    public MergeTarget addRepeatedField(
-        Descriptors.FieldDescriptor field, Object value) {
+    @Override
+    public MergeTarget addRepeatedField(Descriptors.FieldDescriptor field, Object value) {
       builder.addRepeatedField(field, value);
       return this;
     }
@@ -426,25 +431,30 @@ class MessageReflection {
       return builder.getOneofFieldDescriptor(oneof);
     }
 
+    @Override
     public ContainerType getContainerType() {
       return ContainerType.MESSAGE;
     }
 
+    @Override
     public ExtensionRegistry.ExtensionInfo findExtensionByName(
         ExtensionRegistry registry, String name) {
       return registry.findImmutableExtensionByName(name);
     }
 
+    @Override
     public ExtensionRegistry.ExtensionInfo findExtensionByNumber(
-        ExtensionRegistry registry, Descriptors.Descriptor containingType,
-        int fieldNumber) {
+        ExtensionRegistry registry, Descriptors.Descriptor containingType, int fieldNumber) {
       return registry.findImmutableExtensionByNumber(containingType,
           fieldNumber);
     }
 
-    public Object parseGroup(CodedInputStream input,
+    @Override
+    public Object parseGroup(
+        CodedInputStream input,
         ExtensionRegistryLite extensionRegistry,
-        Descriptors.FieldDescriptor field, Message defaultInstance)
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
         throws IOException {
       Message.Builder subBuilder;
       // When default instance is not null. The field is an extension field.
@@ -463,9 +473,12 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
-    public Object parseMessage(CodedInputStream input,
+    @Override
+    public Object parseMessage(
+        CodedInputStream input,
         ExtensionRegistryLite extensionRegistry,
-        Descriptors.FieldDescriptor field, Message defaultInstance)
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
         throws IOException {
       Message.Builder subBuilder;
       // When default instance is not null. The field is an extension field.
@@ -484,9 +497,12 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
-    public Object parseMessageFromBytes(ByteString bytes,
+    @Override
+    public Object parseMessageFromBytes(
+        ByteString bytes,
         ExtensionRegistryLite extensionRegistry,
-        Descriptors.FieldDescriptor field, Message defaultInstance)
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
         throws IOException {
       Message.Builder subBuilder;
       // When default instance is not null. The field is an extension field.
@@ -505,8 +521,9 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
-    public MergeTarget newMergeTargetForField(Descriptors.FieldDescriptor field,
-        Message defaultInstance) {
+    @Override
+    public MergeTarget newMergeTargetForField(
+        Descriptors.FieldDescriptor field, Message defaultInstance) {
       if (defaultInstance != null) {
         return new BuilderAdapter(
             defaultInstance.newBuilderForType());
@@ -515,8 +532,8 @@ class MessageReflection {
       }
     }
 
-    public WireFormat.Utf8Validation
-        getUtf8Validation(Descriptors.FieldDescriptor descriptor) {
+    @Override
+    public WireFormat.Utf8Validation getUtf8Validation(Descriptors.FieldDescriptor descriptor) {
       if (descriptor.needsUtf8Check()) {
         return WireFormat.Utf8Validation.STRICT;
       }
@@ -528,9 +545,11 @@ class MessageReflection {
       return WireFormat.Utf8Validation.LOOSE;
     }
 
+    @Override
     public Object finish() {
       return builder.buildPartial();
     }
+    
   }
 
 
@@ -542,38 +561,43 @@ class MessageReflection {
       this.extensions = extensions;
     }
 
+    @Override
     public Descriptors.Descriptor getDescriptorForType() {
       throw new UnsupportedOperationException(
           "getDescriptorForType() called on FieldSet object");
     }
 
+    @Override
     public Object getField(Descriptors.FieldDescriptor field) {
       return extensions.getField(field);
     }
 
+    @Override
     public boolean hasField(Descriptors.FieldDescriptor field) {
       return extensions.hasField(field);
     }
 
-    public MergeTarget setField(Descriptors.FieldDescriptor field,
-        Object value) {
+    @Override
+    public MergeTarget setField(Descriptors.FieldDescriptor field, Object value) {
       extensions.setField(field, value);
       return this;
     }
 
+    @Override
     public MergeTarget clearField(Descriptors.FieldDescriptor field) {
       extensions.clearField(field);
       return this;
     }
 
+    @Override
     public MergeTarget setRepeatedField(
         Descriptors.FieldDescriptor field, int index, Object value) {
       extensions.setRepeatedField(field, index, value);
       return this;
     }
 
-    public MergeTarget addRepeatedField(
-        Descriptors.FieldDescriptor field, Object value) {
+    @Override
+    public MergeTarget addRepeatedField(Descriptors.FieldDescriptor field, Object value) {
       extensions.addRepeatedField(field, value);
       return this;
     }
@@ -594,25 +618,31 @@ class MessageReflection {
       return null;
     }
 
+    @Override
     public ContainerType getContainerType() {
       return ContainerType.EXTENSION_SET;
     }
 
+    @Override
     public ExtensionRegistry.ExtensionInfo findExtensionByName(
         ExtensionRegistry registry, String name) {
       return registry.findImmutableExtensionByName(name);
     }
 
+    @Override
     public ExtensionRegistry.ExtensionInfo findExtensionByNumber(
-        ExtensionRegistry registry, Descriptors.Descriptor containingType,
-        int fieldNumber) {
+        ExtensionRegistry registry, Descriptors.Descriptor containingType, int fieldNumber) {
       return registry.findImmutableExtensionByNumber(containingType,
           fieldNumber);
     }
 
-    public Object parseGroup(CodedInputStream input,
-        ExtensionRegistryLite registry, Descriptors.FieldDescriptor field,
-        Message defaultInstance) throws IOException {
+    @Override
+    public Object parseGroup(
+        CodedInputStream input,
+        ExtensionRegistryLite registry,
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
+        throws IOException {
       Message.Builder subBuilder =
           defaultInstance.newBuilderForType();
       if (!field.isRepeated()) {
@@ -625,9 +655,13 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
-    public Object parseMessage(CodedInputStream input,
-        ExtensionRegistryLite registry, Descriptors.FieldDescriptor field,
-        Message defaultInstance) throws IOException {
+    @Override
+    public Object parseMessage(
+        CodedInputStream input,
+        ExtensionRegistryLite registry,
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
+        throws IOException {
       Message.Builder subBuilder =
           defaultInstance.newBuilderForType();
       if (!field.isRepeated()) {
@@ -640,9 +674,13 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
-    public Object parseMessageFromBytes(ByteString bytes,
-        ExtensionRegistryLite registry, Descriptors.FieldDescriptor field,
-        Message defaultInstance) throws IOException {
+    @Override
+    public Object parseMessageFromBytes(
+        ByteString bytes,
+        ExtensionRegistryLite registry,
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
+        throws IOException {
       Message.Builder subBuilder =  defaultInstance.newBuilderForType();
       if (!field.isRepeated()) {
         Message originalMessage = (Message) getField(field);
@@ -654,14 +692,15 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
+    @Override
     public MergeTarget newMergeTargetForField(
         Descriptors.FieldDescriptor descriptor, Message defaultInstance) {
       throw new UnsupportedOperationException(
           "newMergeTargetForField() called on FieldSet object");
     }
 
-    public WireFormat.Utf8Validation
-        getUtf8Validation(Descriptors.FieldDescriptor descriptor) {
+    @Override
+    public WireFormat.Utf8Validation getUtf8Validation(Descriptors.FieldDescriptor descriptor) {
       if (descriptor.needsUtf8Check()) {
         return WireFormat.Utf8Validation.STRICT;
       }
@@ -669,10 +708,12 @@ class MessageReflection {
       return WireFormat.Utf8Validation.LOOSE;
     }
 
+    @Override
     public Object finish() {
       throw new UnsupportedOperationException(
           "finish() called on FieldSet object");
     }
+    
   }
 
   /**
diff --git a/java/core/src/main/java/com/google/protobuf/ProtobufArrayList.java b/java/core/src/main/java/com/google/protobuf/ProtobufArrayList.java
index d2f82ac5..81255ec2 100644
--- a/java/core/src/main/java/com/google/protobuf/ProtobufArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/ProtobufArrayList.java
@@ -38,7 +38,7 @@ import java.util.List;
 /**
  * Implements {@link ProtobufList} for non-primitive and {@link String} types.
  */
-class ProtobufArrayList<E> extends AbstractProtobufList<E> {
+final class ProtobufArrayList<E> extends AbstractProtobufList<E> {
 
   private static final ProtobufArrayList<Object> EMPTY_LIST = new ProtobufArrayList<Object>();
   static {
@@ -51,17 +51,23 @@ class ProtobufArrayList<E> extends AbstractProtobufList<E> {
   }
   
   private final List<E> list;
-  
+
   ProtobufArrayList() {
-    list = new ArrayList<E>();
+    this(new ArrayList<E>(DEFAULT_CAPACITY));
   }
   
-  ProtobufArrayList(List<E> toCopy) {
-    list = new ArrayList<E>(toCopy);
+  private ProtobufArrayList(List<E> list) {
+    this.list = list;
   }
-  
-  ProtobufArrayList(int capacity) {
-    list = new ArrayList<E>(capacity);
+
+  @Override
+  public ProtobufArrayList<E> mutableCopyWithCapacity(int capacity) {
+    if (capacity < size()) {
+      throw new IllegalArgumentException();
+    }
+    List<E> newList = new ArrayList<E>(capacity);
+    newList.addAll(list);
+    return new ProtobufArrayList<E>(newList);
   }
   
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/ProtocolMessageEnum.java b/java/core/src/main/java/com/google/protobuf/ProtocolMessageEnum.java
index 0c8df989..a596d301 100644
--- a/java/core/src/main/java/com/google/protobuf/ProtocolMessageEnum.java
+++ b/java/core/src/main/java/com/google/protobuf/ProtocolMessageEnum.java
@@ -42,6 +42,7 @@ public interface ProtocolMessageEnum extends Internal.EnumLite {
   /**
    * Return the value's numeric value as defined in the .proto file.
    */
+  @Override
   int getNumber();
 
   /**
diff --git a/java/core/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java b/java/core/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java
index f91cdbce..29f567dc 100644
--- a/java/core/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java
+++ b/java/core/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java
@@ -579,7 +579,7 @@ public class RepeatedFieldBuilder
     }
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void markDirty() {
     onChanged();
   }
@@ -621,10 +621,12 @@ public class RepeatedFieldBuilder
       this.builder = builder;
     }
 
+    @Override
     public int size() {
       return this.builder.getCount();
     }
 
+    @Override
     public MType get(int index) {
       return builder.getMessage(index);
     }
@@ -654,10 +656,12 @@ public class RepeatedFieldBuilder
       this.builder = builder;
     }
 
+    @Override
     public int size() {
       return this.builder.getCount();
     }
 
+    @Override
     public BType get(int index) {
       return builder.getBuilder(index);
     }
@@ -687,10 +691,12 @@ public class RepeatedFieldBuilder
       this.builder = builder;
     }
 
+    @Override
     public int size() {
       return this.builder.getCount();
     }
 
+    @Override
     public IType get(int index) {
       return builder.getMessageOrBuilder(index);
     }
diff --git a/java/core/src/main/java/com/google/protobuf/RpcUtil.java b/java/core/src/main/java/com/google/protobuf/RpcUtil.java
index 694b8d13..f7d555ae 100644
--- a/java/core/src/main/java/com/google/protobuf/RpcUtil.java
+++ b/java/core/src/main/java/com/google/protobuf/RpcUtil.java
@@ -71,6 +71,7 @@ public final class RpcUtil {
       final Class<Type> originalClass,
       final Type defaultInstance) {
     return new RpcCallback<Message>() {
+      @Override
       public void run(final Message parameter) {
         Type typedParameter;
         try {
@@ -107,8 +108,9 @@ public final class RpcUtil {
     return new RpcCallback<ParameterType>() {
       private boolean alreadyCalled = false;
 
+      @Override
       public void run(final ParameterType parameter) {
-        synchronized(this) {
+        synchronized (this) {
           if (alreadyCalled) {
             throw new AlreadyCalledException();
           }
diff --git a/java/core/src/main/java/com/google/protobuf/SingleFieldBuilder.java b/java/core/src/main/java/com/google/protobuf/SingleFieldBuilder.java
index aba65e32..941b5def 100644
--- a/java/core/src/main/java/com/google/protobuf/SingleFieldBuilder.java
+++ b/java/core/src/main/java/com/google/protobuf/SingleFieldBuilder.java
@@ -234,7 +234,7 @@ public class SingleFieldBuilder
     }
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void markDirty() {
     onChanged();
   }
diff --git a/java/core/src/main/java/com/google/protobuf/SmallSortedMap.java b/java/core/src/main/java/com/google/protobuf/SmallSortedMap.java
index dff19328..409fec10 100644
--- a/java/core/src/main/java/com/google/protobuf/SmallSortedMap.java
+++ b/java/core/src/main/java/com/google/protobuf/SmallSortedMap.java
@@ -411,22 +411,22 @@ class SmallSortedMap<K extends Comparable<K>, V> extends AbstractMap<K, V> {
       this.value = value;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public K getKey() {
       return key;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public V getValue() {
       return value;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public int compareTo(Entry other) {
       return getKey().compareTo(other.getKey());
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public V setValue(V newValue) {
       checkMutable();
       final V oldValue = this.value;
@@ -535,13 +535,13 @@ class SmallSortedMap<K extends Comparable<K>, V> extends AbstractMap<K, V> {
     private boolean nextCalledBeforeRemove;
     private Iterator<Map.Entry<K, V>> lazyOverflowIterator;
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public boolean hasNext() {
       return (pos + 1) < entryList.size() ||
           getOverflowIterator().hasNext();
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public Map.Entry<K, V> next() {
       nextCalledBeforeRemove = true;
       // Always increment pos so that we know whether the last returned value
@@ -552,7 +552,7 @@ class SmallSortedMap<K extends Comparable<K>, V> extends AbstractMap<K, V> {
       return getOverflowIterator().next();
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public void remove() {
       if (!nextCalledBeforeRemove) {
         throw new IllegalStateException("remove() was called before next()");
@@ -588,31 +588,83 @@ class SmallSortedMap<K extends Comparable<K>, V> extends AbstractMap<K, V> {
    */
   private static class EmptySet {
 
-    private static final Iterator<Object> ITERATOR = new Iterator<Object>() {
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
-      public boolean hasNext() {
-        return false;
-      }
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
-      public Object next() {
-        throw new NoSuchElementException();
-      }
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
-      public void remove() {
-        throw new UnsupportedOperationException();
-      }
-    };
+    private static final Iterator<Object> ITERATOR =
+        new Iterator<Object>() {
+          @Override
+          public boolean hasNext() {
+            return false;
+          }
+          @Override
+          public Object next() {
+            throw new NoSuchElementException();
+          }
+          @Override
+          public void remove() {
+            throw new UnsupportedOperationException();
+          }
+        };
 
-    private static final Iterable<Object> ITERABLE = new Iterable<Object>() {
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
-      public Iterator<Object> iterator() {
-        return ITERATOR;
-      }
-    };
+    private static final Iterable<Object> ITERABLE =
+        new Iterable<Object>() {
+          @Override
+          public Iterator<Object> iterator() {
+            return ITERATOR;
+          }
+        };
 
     @SuppressWarnings("unchecked")
     static <T> Iterable<T> iterable() {
       return (Iterable<T>) ITERABLE;
     }
   }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    
+    if (!(o instanceof SmallSortedMap)) {
+      return super.equals(o);
+    }
+    
+    SmallSortedMap<?, ?> other = (SmallSortedMap<?, ?>) o;
+    final int size = size();
+    if (size != other.size()) {
+      return false;
+    }
+    
+    // Best effort try to avoid allocating an entry set.
+    final int numArrayEntries = getNumArrayEntries();
+    if (numArrayEntries != other.getNumArrayEntries()) {
+      return entrySet().equals(other.entrySet());
+    }
+    
+    for (int i = 0; i < numArrayEntries; i++) {
+      if (!getArrayEntryAt(i).equals(other.getArrayEntryAt(i))) {
+        return false;
+      }
+    }
+    
+    if (numArrayEntries != size) {
+      return overflowEntries.equals(other.overflowEntries);
+    }
+    
+    
+    return true;
+  }
+  
+  @Override
+  public int hashCode() {
+    int h = 0;
+    final int listSize = getNumArrayEntries();
+    for (int i = 0; i < listSize; i++) {
+      h += entryList.get(i).hashCode();
+    }
+    // Avoid the iterator allocation if possible.
+    if (getNumOverflowEntries() > 0) {
+      h += overflowEntries.hashCode();
+    }
+    return h;
+  }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/TextFormat.java b/java/core/src/main/java/com/google/protobuf/TextFormat.java
index edf114fa..c1c328fc 100644
--- a/java/core/src/main/java/com/google/protobuf/TextFormat.java
+++ b/java/core/src/main/java/com/google/protobuf/TextFormat.java
@@ -965,11 +965,13 @@ public final class TextFormat {
      */
     public boolean consumeBoolean() throws ParseException {
       if (currentToken.equals("true")
+          || currentToken.equals("True")
           || currentToken.equals("t")
           || currentToken.equals("1")) {
         nextToken();
         return true;
       } else if (currentToken.equals("false")
+          || currentToken.equals("False")
           || currentToken.equals("f")
           || currentToken.equals("0")) {
         nextToken();
diff --git a/java/core/src/main/java/com/google/protobuf/UnknownFieldSet.java b/java/core/src/main/java/com/google/protobuf/UnknownFieldSet.java
index 7cd2250e..c906420d 100644
--- a/java/core/src/main/java/com/google/protobuf/UnknownFieldSet.java
+++ b/java/core/src/main/java/com/google/protobuf/UnknownFieldSet.java
@@ -76,6 +76,7 @@ public final class UnknownFieldSet implements MessageLite {
   public static UnknownFieldSet getDefaultInstance() {
     return defaultInstance;
   }
+  @Override
   public UnknownFieldSet getDefaultInstanceForType() {
     return defaultInstance;
   }
@@ -126,6 +127,7 @@ public final class UnknownFieldSet implements MessageLite {
   }
 
   /** Serializes the set and writes it to {@code output}. */
+  @Override
   public void writeTo(final CodedOutputStream output) throws IOException {
     for (final Map.Entry<Integer, Field> entry : fields.entrySet()) {
       entry.getValue().writeTo(entry.getKey(), output);
@@ -146,6 +148,7 @@ public final class UnknownFieldSet implements MessageLite {
    * Serializes the message to a {@code ByteString} and returns it. This is
    * just a trivial wrapper around {@link #writeTo(CodedOutputStream)}.
    */
+  @Override
   public ByteString toByteString() {
     try {
       final ByteString.CodedBuilder out =
@@ -163,6 +166,7 @@ public final class UnknownFieldSet implements MessageLite {
    * Serializes the message to a {@code byte} array and returns it.  This is
    * just a trivial wrapper around {@link #writeTo(CodedOutputStream)}.
    */
+  @Override
   public byte[] toByteArray() {
     try {
       final byte[] result = new byte[getSerializedSize()];
@@ -181,12 +185,14 @@ public final class UnknownFieldSet implements MessageLite {
    * Serializes the message and writes it to {@code output}.  This is just a
    * trivial wrapper around {@link #writeTo(CodedOutputStream)}.
    */
+  @Override
   public void writeTo(final OutputStream output) throws IOException {
     final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output);
     writeTo(codedOutput);
     codedOutput.flush();
   }
 
+  @Override
   public void writeDelimitedTo(OutputStream output) throws IOException {
     final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output);
     codedOutput.writeRawVarint32(getSerializedSize());
@@ -195,6 +201,7 @@ public final class UnknownFieldSet implements MessageLite {
   }
 
   /** Get the number of bytes required to encode this set. */
+  @Override
   public int getSerializedSize() {
     int result = 0;
     for (final Map.Entry<Integer, Field> entry : fields.entrySet()) {
@@ -228,6 +235,7 @@ public final class UnknownFieldSet implements MessageLite {
     return result;
   }
 
+  @Override
   public boolean isInitialized() {
     // UnknownFieldSets do not have required fields, so they are always
     // initialized.
@@ -258,10 +266,12 @@ public final class UnknownFieldSet implements MessageLite {
     return newBuilder().mergeFrom(input).build();
   }
 
+  @Override
   public Builder newBuilderForType() {
     return newBuilder();
   }
 
+  @Override
   public Builder toBuilder() {
     return newBuilder().mergeFrom(this);
   }
@@ -329,6 +339,7 @@ public final class UnknownFieldSet implements MessageLite {
      * in undefined behavior and can cause a {@code NullPointerException} to be
      * thrown.
      */
+    @Override
     public UnknownFieldSet build() {
       getFieldBuilder(0);  // Force lastField to be built.
       final UnknownFieldSet result;
@@ -341,6 +352,7 @@ public final class UnknownFieldSet implements MessageLite {
       return result;
     }
 
+    @Override
     public UnknownFieldSet buildPartial() {
       // No required fields, so this is the same as build().
       return build();
@@ -353,6 +365,7 @@ public final class UnknownFieldSet implements MessageLite {
           new UnknownFieldSet(fields));
     }
 
+    @Override
     public UnknownFieldSet getDefaultInstanceForType() {
       return UnknownFieldSet.getDefaultInstance();
     }
@@ -364,6 +377,7 @@ public final class UnknownFieldSet implements MessageLite {
     }
 
     /** Reset the builder to an empty set. */
+    @Override
     public Builder clear() {
       reinitialize();
       return this;
@@ -487,6 +501,7 @@ public final class UnknownFieldSet implements MessageLite {
      * Parse an entire message from {@code input} and merge its fields into
      * this set.
      */
+    @Override
     public Builder mergeFrom(final CodedInputStream input) throws IOException {
       while (true) {
         final int tag = input.readTag();
@@ -536,8 +551,8 @@ public final class UnknownFieldSet implements MessageLite {
      * set being built.  This is just a small wrapper around
      * {@link #mergeFrom(CodedInputStream)}.
      */
-    public Builder mergeFrom(final ByteString data)
-        throws InvalidProtocolBufferException {
+    @Override
+    public Builder mergeFrom(final ByteString data) throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input = data.newCodedInput();
         mergeFrom(input);
@@ -557,8 +572,8 @@ public final class UnknownFieldSet implements MessageLite {
      * set being built.  This is just a small wrapper around
      * {@link #mergeFrom(CodedInputStream)}.
      */
-    public Builder mergeFrom(final byte[] data)
-        throws InvalidProtocolBufferException {
+    @Override
+    public Builder mergeFrom(final byte[] data) throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input = CodedInputStream.newInstance(data);
         mergeFrom(input);
@@ -578,6 +593,7 @@ public final class UnknownFieldSet implements MessageLite {
      * set being built.  This is just a small wrapper around
      * {@link #mergeFrom(CodedInputStream)}.
      */
+    @Override
     public Builder mergeFrom(final InputStream input) throws IOException {
       final CodedInputStream codedInput = CodedInputStream.newInstance(input);
       mergeFrom(codedInput);
@@ -585,8 +601,8 @@ public final class UnknownFieldSet implements MessageLite {
       return this;
     }
 
-    public boolean mergeDelimitedFrom(InputStream input)
-        throws IOException {
+    @Override
+    public boolean mergeDelimitedFrom(InputStream input) throws IOException {
       final int firstByte = input.read();
       if (firstByte == -1) {
         return false;
@@ -597,30 +613,29 @@ public final class UnknownFieldSet implements MessageLite {
       return true;
     }
 
-    public boolean mergeDelimitedFrom(
-        InputStream input,
-        ExtensionRegistryLite extensionRegistry) throws IOException {
+    @Override
+    public boolean mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException {
       // UnknownFieldSet has no extensions.
       return mergeDelimitedFrom(input);
     }
 
-    public Builder mergeFrom(
-        CodedInputStream input,
-        ExtensionRegistryLite extensionRegistry) throws IOException {
+    @Override
+    public Builder mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException {
       // UnknownFieldSet has no extensions.
       return mergeFrom(input);
     }
 
-    public Builder mergeFrom(
-        ByteString data,
-        ExtensionRegistryLite extensionRegistry)
+    @Override
+    public Builder mergeFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       // UnknownFieldSet has no extensions.
       return mergeFrom(data);
     }
 
-    public Builder mergeFrom(byte[] data, int off, int len)
-        throws InvalidProtocolBufferException {
+    @Override
+    public Builder mergeFrom(byte[] data, int off, int len) throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input =
             CodedInputStream.newInstance(data, off, len);
@@ -636,29 +651,37 @@ public final class UnknownFieldSet implements MessageLite {
       }
     }
 
-    public Builder mergeFrom(
-        byte[] data,
-        ExtensionRegistryLite extensionRegistry)
+    @Override
+    public Builder mergeFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       // UnknownFieldSet has no extensions.
       return mergeFrom(data);
     }
 
-    public Builder mergeFrom(
-        byte[] data, int off, int len,
-        ExtensionRegistryLite extensionRegistry)
+    @Override
+    public Builder mergeFrom(byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       // UnknownFieldSet has no extensions.
       return mergeFrom(data, off, len);
     }
 
-    public Builder mergeFrom(
-        InputStream input,
-        ExtensionRegistryLite extensionRegistry) throws IOException {
+    @Override
+    public Builder mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException {
       // UnknownFieldSet has no extensions.
       return mergeFrom(input);
     }
 
+    @Override
+    public Builder mergeFrom(MessageLite m) {
+      if (m instanceof UnknownFieldSet) {
+        return mergeFrom((UnknownFieldSet) m);
+      }
+      throw new IllegalArgumentException(
+          "mergeFrom(MessageLite) can only merge messages of the same type.");
+    }
+
+    @Override
     public boolean isInitialized() {
       // UnknownFieldSets do not have required fields, so they are always
       // initialized.
@@ -987,6 +1010,7 @@ public final class UnknownFieldSet implements MessageLite {
    * Parser to implement MessageLite interface.
    */
   public static final class Parser extends AbstractParser<UnknownFieldSet> {
+    @Override
     public UnknownFieldSet parsePartialFrom(
         CodedInputStream input, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
@@ -1004,6 +1028,7 @@ public final class UnknownFieldSet implements MessageLite {
   }
 
   private static final Parser PARSER = new Parser();
+  @Override
   public final Parser getParserForType() {
     return PARSER;
   }
diff --git a/java/core/src/main/java/com/google/protobuf/UnmodifiableLazyStringList.java b/java/core/src/main/java/com/google/protobuf/UnmodifiableLazyStringList.java
index 5257c5a2..30e87911 100644
--- a/java/core/src/main/java/com/google/protobuf/UnmodifiableLazyStringList.java
+++ b/java/core/src/main/java/com/google/protobuf/UnmodifiableLazyStringList.java
@@ -68,42 +68,42 @@ public class UnmodifiableLazyStringList extends AbstractList<String>
     return list.size();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public ByteString getByteString(int index) {
     return list.getByteString(index);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void add(ByteString element) {
     throw new UnsupportedOperationException();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void set(int index, ByteString element) {
     throw new UnsupportedOperationException();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public boolean addAllByteString(Collection<? extends ByteString> element) {
     throw new UnsupportedOperationException();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public byte[] getByteArray(int index) {
     return list.getByteArray(index);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void add(byte[] element) {
     throw new UnsupportedOperationException();
   }
   
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void set(int index, byte[] element) {
     throw new UnsupportedOperationException();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public boolean addAllByteArray(Collection<byte[]> element) {
     throw new UnsupportedOperationException();
   }
@@ -113,47 +113,47 @@ public class UnmodifiableLazyStringList extends AbstractList<String>
     return new ListIterator<String>() {
       ListIterator<String> iter = list.listIterator(index);
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public boolean hasNext() {
         return iter.hasNext();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public String next() {
         return iter.next();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public boolean hasPrevious() {
         return iter.hasPrevious();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public String previous() {
         return iter.previous();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public int nextIndex() {
         return iter.nextIndex();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public int previousIndex() {
         return iter.previousIndex();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public void remove() {
         throw new UnsupportedOperationException();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public void set(String o) {
         throw new UnsupportedOperationException();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public void add(String o) {
         throw new UnsupportedOperationException();
       }
@@ -165,45 +165,45 @@ public class UnmodifiableLazyStringList extends AbstractList<String>
     return new Iterator<String>() {
       Iterator<String> iter = list.iterator();
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public boolean hasNext() {
         return iter.hasNext();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public String next() {
         return iter.next();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public void remove() {
         throw new UnsupportedOperationException();
       }
     };
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public List<?> getUnderlyingElements() {
     // The returned value is already unmodifiable.
     return list.getUnderlyingElements();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void mergeFrom(LazyStringList other) {
     throw new UnsupportedOperationException();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public List<byte[]> asByteArrayList() {
     return Collections.unmodifiableList(list.asByteArrayList());
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public List<ByteString> asByteStringList() {
     return Collections.unmodifiableList(list.asByteStringList());
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public LazyStringList getUnmodifiableView() {
     return this;
   }
diff --git a/java/core/src/main/java/com/google/protobuf/WireFormat.java b/java/core/src/main/java/com/google/protobuf/WireFormat.java
index 8dbe1ae3..6a58b081 100644
--- a/java/core/src/main/java/com/google/protobuf/WireFormat.java
+++ b/java/core/src/main/java/com/google/protobuf/WireFormat.java
@@ -116,16 +116,24 @@ public final class WireFormat {
     FIXED32 (JavaType.INT        , WIRETYPE_FIXED32         ),
     BOOL    (JavaType.BOOLEAN    , WIRETYPE_VARINT          ),
     STRING  (JavaType.STRING     , WIRETYPE_LENGTH_DELIMITED) {
-      public boolean isPackable() { return false; }
+      @Override
+      public boolean isPackable() {
+        return false; }
     },
     GROUP   (JavaType.MESSAGE    , WIRETYPE_START_GROUP     ) {
-      public boolean isPackable() { return false; }
+      @Override
+      public boolean isPackable() {
+        return false; }
     },
     MESSAGE (JavaType.MESSAGE    , WIRETYPE_LENGTH_DELIMITED) {
-      public boolean isPackable() { return false; }
+      @Override
+      public boolean isPackable() {
+        return false; }
     },
     BYTES   (JavaType.BYTE_STRING, WIRETYPE_LENGTH_DELIMITED) {
-      public boolean isPackable() { return false; }
+      @Override
+      public boolean isPackable() {
+        return false; }
     },
     UINT32  (JavaType.INT        , WIRETYPE_VARINT          ),
     ENUM    (JavaType.ENUM       , WIRETYPE_VARINT          ),
@@ -170,18 +178,21 @@ public final class WireFormat {
   enum Utf8Validation {
     /** Eagerly parses to String; silently accepts invalid UTF8 bytes. */
     LOOSE {
+      @Override
       Object readString(CodedInputStream input) throws IOException {
         return input.readString();
       }
     },
     /** Eagerly parses to String; throws an IOException on invalid bytes. */
     STRICT {
+      @Override
       Object readString(CodedInputStream input) throws IOException {
         return input.readStringRequireUtf8();
       }
     },
     /** Keep data as ByteString; validation/conversion to String is lazy. */
     LAZY {
+      @Override
       Object readString(CodedInputStream input) throws IOException {
         return input.readBytes();
       }
diff --git a/java/core/src/test/java/com/google/protobuf/AbstractMessageTest.java b/java/core/src/test/java/com/google/protobuf/AbstractMessageTest.java
index 1e57b647..7dc9fc15 100644
--- a/java/core/src/test/java/com/google/protobuf/AbstractMessageTest.java
+++ b/java/core/src/test/java/com/google/protobuf/AbstractMessageTest.java
@@ -64,35 +64,44 @@ public class AbstractMessageTest extends TestCase {
       this.wrappedMessage = wrappedMessage;
     }
 
+    @Override
     public Descriptors.Descriptor getDescriptorForType() {
       return wrappedMessage.getDescriptorForType();
     }
+    @Override
     public AbstractMessageWrapper getDefaultInstanceForType() {
       return new AbstractMessageWrapper(
         wrappedMessage.getDefaultInstanceForType());
     }
+    @Override
     public Map<Descriptors.FieldDescriptor, Object> getAllFields() {
       return wrappedMessage.getAllFields();
     }
+    @Override
     public boolean hasField(Descriptors.FieldDescriptor field) {
       return wrappedMessage.hasField(field);
     }
+    @Override
     public Object getField(Descriptors.FieldDescriptor field) {
       return wrappedMessage.getField(field);
     }
+    @Override
     public int getRepeatedFieldCount(Descriptors.FieldDescriptor field) {
       return wrappedMessage.getRepeatedFieldCount(field);
     }
-    public Object getRepeatedField(
-        Descriptors.FieldDescriptor field, int index) {
+    @Override
+    public Object getRepeatedField(Descriptors.FieldDescriptor field, int index) {
       return wrappedMessage.getRepeatedField(field, index);
     }
+    @Override
     public UnknownFieldSet getUnknownFields() {
       return wrappedMessage.getUnknownFields();
     }
+    @Override
     public Builder newBuilderForType() {
       return new Builder(wrappedMessage.newBuilderForType());
     }
+    @Override
     public Builder toBuilder() {
       return new Builder(wrappedMessage.toBuilder());
     }
@@ -104,65 +113,80 @@ public class AbstractMessageTest extends TestCase {
         this.wrappedBuilder = wrappedBuilder;
       }
 
+      @Override
       public AbstractMessageWrapper build() {
         return new AbstractMessageWrapper(wrappedBuilder.build());
       }
+      @Override
       public AbstractMessageWrapper buildPartial() {
         return new AbstractMessageWrapper(wrappedBuilder.buildPartial());
       }
+      @Override
       public Builder clone() {
         return new Builder(wrappedBuilder.clone());
       }
+      @Override
       public boolean isInitialized() {
         return clone().buildPartial().isInitialized();
       }
+      @Override
       public Descriptors.Descriptor getDescriptorForType() {
         return wrappedBuilder.getDescriptorForType();
       }
+      @Override
       public AbstractMessageWrapper getDefaultInstanceForType() {
         return new AbstractMessageWrapper(
           wrappedBuilder.getDefaultInstanceForType());
       }
+      @Override
       public Map<Descriptors.FieldDescriptor, Object> getAllFields() {
         return wrappedBuilder.getAllFields();
       }
+      @Override
       public Builder newBuilderForField(Descriptors.FieldDescriptor field) {
         return new Builder(wrappedBuilder.newBuilderForField(field));
       }
+      @Override
       public boolean hasField(Descriptors.FieldDescriptor field) {
         return wrappedBuilder.hasField(field);
       }
+      @Override
       public Object getField(Descriptors.FieldDescriptor field) {
         return wrappedBuilder.getField(field);
       }
+      @Override
       public Builder setField(Descriptors.FieldDescriptor field, Object value) {
         wrappedBuilder.setField(field, value);
         return this;
       }
+      @Override
       public Builder clearField(Descriptors.FieldDescriptor field) {
         wrappedBuilder.clearField(field);
         return this;
       }
+      @Override
       public int getRepeatedFieldCount(Descriptors.FieldDescriptor field) {
         return wrappedBuilder.getRepeatedFieldCount(field);
       }
-      public Object getRepeatedField(
-          Descriptors.FieldDescriptor field, int index) {
+      @Override
+      public Object getRepeatedField(Descriptors.FieldDescriptor field, int index) {
         return wrappedBuilder.getRepeatedField(field, index);
       }
-      public Builder setRepeatedField(Descriptors.FieldDescriptor field,
-                                      int index, Object value) {
+      @Override
+      public Builder setRepeatedField(Descriptors.FieldDescriptor field, int index, Object value) {
         wrappedBuilder.setRepeatedField(field, index, value);
         return this;
       }
-      public Builder addRepeatedField(
-          Descriptors.FieldDescriptor field, Object value) {
+      @Override
+      public Builder addRepeatedField(Descriptors.FieldDescriptor field, Object value) {
         wrappedBuilder.addRepeatedField(field, value);
         return this;
       }
+      @Override
       public UnknownFieldSet getUnknownFields() {
         return wrappedBuilder.getUnknownFields();
       }
+      @Override
       public Builder setUnknownFields(UnknownFieldSet unknownFields) {
         wrappedBuilder.setUnknownFields(unknownFields);
         return this;
@@ -172,6 +196,7 @@ public class AbstractMessageTest extends TestCase {
         return wrappedBuilder.getFieldBuilder(field);
       }
     }
+    @Override
     public Parser<? extends Message> getParserForType() {
       return wrappedMessage.getParserForType();
     }
diff --git a/java/core/src/test/java/com/google/protobuf/BooleanArrayListTest.java b/java/core/src/test/java/com/google/protobuf/BooleanArrayListTest.java
index b8ad1fe4..24b96c60 100644
--- a/java/core/src/test/java/com/google/protobuf/BooleanArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/BooleanArrayListTest.java
@@ -73,20 +73,6 @@ public class BooleanArrayListTest extends TestCase {
     assertImmutable(list);
   }
   
-  public void testCopyConstructor() {
-    BooleanArrayList copy = new BooleanArrayList(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new BooleanArrayList(BooleanArrayList.emptyList());
-    assertEquals(BooleanArrayList.emptyList(), copy);
-    
-    copy = new BooleanArrayList(asList(false, false, true));
-    assertEquals(asList(false, false, true), copy);
-
-    copy = new BooleanArrayList(Collections.<Boolean>emptyList());
-    assertEquals(BooleanArrayList.emptyList(), copy);
-  }
-  
   public void testModificationWithIteration() {
     list.addAll(asList(true, false, false, true));
     Iterator<Boolean> iterator = list.iterator();
diff --git a/java/core/src/test/java/com/google/protobuf/CodedInputStreamTest.java b/java/core/src/test/java/com/google/protobuf/CodedInputStreamTest.java
index a1d6f1be..ca940ced 100644
--- a/java/core/src/test/java/com/google/protobuf/CodedInputStreamTest.java
+++ b/java/core/src/test/java/com/google/protobuf/CodedInputStreamTest.java
@@ -81,10 +81,12 @@ public class CodedInputStreamTest extends TestCase {
       this.blockSize = blockSize;
     }
 
+    @Override
     public int read(byte[] b) throws IOException {
       return super.read(b, 0, Math.min(b.length, blockSize));
     }
 
+    @Override
     public int read(byte[] b, int off, int len) throws IOException {
       return super.read(b, off, Math.min(len, blockSize));
     }
diff --git a/java/core/src/test/java/com/google/protobuf/CodedOutputStreamTest.java b/java/core/src/test/java/com/google/protobuf/CodedOutputStreamTest.java
index 6018ea55..33aa4357 100644
--- a/java/core/src/test/java/com/google/protobuf/CodedOutputStreamTest.java
+++ b/java/core/src/test/java/com/google/protobuf/CodedOutputStreamTest.java
@@ -30,6 +30,7 @@
 
 package com.google.protobuf;
 
+import com.google.protobuf.CodedOutputStream.OutOfSpaceException;
 import protobuf_unittest.UnittestProto.SparseEnumMessage;
 import protobuf_unittest.UnittestProto.TestAllTypes;
 import protobuf_unittest.UnittestProto.TestPackedTypes;
@@ -50,118 +51,180 @@ import java.util.List;
  * @author kenton@google.com Kenton Varda
  */
 public class CodedOutputStreamTest extends TestCase {
-  /**
-   * Helper to construct a byte array from a bunch of bytes.  The inputs are
-   * actually ints so that I can use hex notation and not get stupid errors
-   * about precision.
-   */
-  private byte[] bytes(int... bytesAsInts) {
-    byte[] bytes = new byte[bytesAsInts.length];
-    for (int i = 0; i < bytesAsInts.length; i++) {
-      bytes[i] = (byte) bytesAsInts[i];
-    }
-    return bytes;
+  private interface Coder {
+    CodedOutputStream stream();
+
+    byte[] toByteArray();
+
+    OutputType getOutputType();
   }
 
-  /** Arrays.asList() does not work with arrays of primitives.  :( */
-  private List<Byte> toList(byte[] bytes) {
-    List<Byte> result = new ArrayList<Byte>();
-    for (byte b : bytes) {
-      result.add(b);
+  private static final class OutputStreamCoder implements Coder {
+    private final CodedOutputStream stream;
+    private final ByteArrayOutputStream output;
+
+    OutputStreamCoder(int size) {
+      output = new ByteArrayOutputStream();
+      stream = CodedOutputStream.newInstance(output, size);
+    }
+
+    @Override
+    public CodedOutputStream stream() {
+      return stream;
+    }
+
+    @Override
+    public byte[] toByteArray() {
+      return output.toByteArray();
+    }
+
+    @Override
+    public OutputType getOutputType() {
+      return OutputType.STREAM;
     }
-    return result;
   }
 
-  private void assertEqualBytes(byte[] a, byte[] b) {
-    assertEquals(toList(a), toList(b));
+  private static final class ArrayCoder implements Coder {
+    private final CodedOutputStream stream;
+    private final byte[] bytes;
+
+    ArrayCoder(int size) {
+      bytes = new byte[size];
+      stream = CodedOutputStream.newInstance(bytes);
+    }
+
+    @Override
+    public CodedOutputStream stream() {
+      return stream;
+    }
+
+    @Override
+    public byte[] toByteArray() {
+      return Arrays.copyOf(bytes, stream.getTotalBytesWritten());
+    }
+
+    @Override
+    public OutputType getOutputType() {
+      return OutputType.ARRAY;
+    }
   }
 
-  /**
-   * Writes the given value using writeRawVarint32() and writeRawVarint64() and
-   * checks that the result matches the given bytes.
-   */
-  private void assertWriteVarint(byte[] data, long value) throws Exception {
-    // Only test 32-bit write if the value fits into an int.
-    if (value == (int) value) {
-      ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-      CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-      output.writeRawVarint32((int) value);
-      output.flush();
-      assertEqualBytes(data, rawOutput.toByteArray());
+  private static final class NioHeapCoder implements Coder {
+    private final CodedOutputStream stream;
+    private final ByteBuffer buffer;
+    private final int initialPosition;
 
-      // Also try computing size.
-      assertEquals(data.length,
-                   CodedOutputStream.computeRawVarint32Size((int) value));
+    NioHeapCoder(int size) {
+      this(size, 0);
     }
 
-    {
-      ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-      CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-      output.writeRawVarint64(value);
-      output.flush();
-      assertEqualBytes(data, rawOutput.toByteArray());
+    NioHeapCoder(int size, int initialPosition) {
+      this.initialPosition = initialPosition;
+      buffer = ByteBuffer.allocate(size);
+      buffer.position(initialPosition);
+      stream = CodedOutputStream.newInstance(buffer);
+    }
 
-      // Also try computing size.
-      assertEquals(data.length,
-                   CodedOutputStream.computeRawVarint64Size(value));
+    @Override
+    public CodedOutputStream stream() {
+      return stream;
     }
 
-    // Try different block sizes.
-    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
-      // Only test 32-bit write if the value fits into an int.
-      if (value == (int) value) {
-        ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-        CodedOutputStream output =
-          CodedOutputStream.newInstance(rawOutput, blockSize);
-        output.writeRawVarint32((int) value);
-        output.flush();
-        assertEqualBytes(data, rawOutput.toByteArray());
-      }
+    @Override
+    public byte[] toByteArray() {
+      ByteBuffer dup = buffer.duplicate();
+      dup.position(initialPosition);
+      dup.limit(buffer.position());
 
-      {
-        ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-        CodedOutputStream output =
-          CodedOutputStream.newInstance(rawOutput, blockSize);
-        output.writeRawVarint64(value);
-        output.flush();
-        assertEqualBytes(data, rawOutput.toByteArray());
-      }
+      byte[] bytes = new byte[dup.remaining()];
+      dup.get(bytes);
+      return bytes;
+    }
+
+    @Override
+    public OutputType getOutputType() {
+      return OutputType.NIO_HEAP;
     }
   }
 
-  private void assertVarintRoundTrip(long value) throws Exception {
-    {
-      ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-      CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-      output.writeRawVarint64(value);
-      output.flush();
-      byte[] bytes = rawOutput.toByteArray();
-      assertEquals(bytes.length, CodedOutputStream.computeRawVarint64Size(value));
-      CodedInputStream input = CodedInputStream.newInstance(new ByteArrayInputStream(bytes));
-      assertEquals(value, input.readRawVarint64());
+  private static final class NioDirectCoder implements Coder {
+    private final int initialPosition;
+    private final CodedOutputStream stream;
+    private final ByteBuffer buffer;
+
+    NioDirectCoder(int size) {
+      this(size, 0);
     }
 
-    if (value == (int) value) {
-      ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-      CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-      output.writeRawVarint32((int) value);
-      output.flush();
-      byte[] bytes = rawOutput.toByteArray();
-      assertEquals(bytes.length, CodedOutputStream.computeRawVarint32Size((int) value));
-      CodedInputStream input = CodedInputStream.newInstance(new ByteArrayInputStream(bytes));
-      assertEquals(value, input.readRawVarint32());
+    NioDirectCoder(int size, int initialPosition) {
+      this.initialPosition = initialPosition;
+      buffer = ByteBuffer.allocateDirect(size);
+      buffer.position(initialPosition);
+      stream = CodedOutputStream.newInstance(buffer);
+    }
+
+    @Override
+    public CodedOutputStream stream() {
+      return stream;
+    }
+
+    @Override
+    public byte[] toByteArray() {
+      ByteBuffer dup = buffer.duplicate();
+      dup.position(initialPosition);
+      dup.limit(buffer.position());
+
+      byte[] bytes = new byte[dup.remaining()];
+      dup.get(bytes);
+      return bytes;
+    }
+
+    @Override
+    public OutputType getOutputType() {
+      return OutputType.NIO_DIRECT;
     }
   }
 
+  private enum OutputType {
+    ARRAY() {
+      @Override
+      Coder newCoder(int size) {
+        return new ArrayCoder(size);
+      }
+    },
+    NIO_HEAP() {
+      @Override
+      Coder newCoder(int size) {
+        return new NioHeapCoder(size);
+      }
+    },
+    NIO_DIRECT() {
+      @Override
+      Coder newCoder(int size) {
+        return new NioDirectCoder(size);
+      }
+    },
+    STREAM() {
+      @Override
+      Coder newCoder(int size) {
+        return new OutputStreamCoder(size);
+      }
+    };
+
+    abstract Coder newCoder(int size);
+  }
+
   /** Checks that invariants are maintained for varint round trip input and output. */
   public void testVarintRoundTrips() throws Exception {
-    assertVarintRoundTrip(0L);
-    for (int bits = 0; bits < 64; bits++) {
-      long value = 1L << bits;
-      assertVarintRoundTrip(value);
-      assertVarintRoundTrip(value + 1);
-      assertVarintRoundTrip(value - 1);
-      assertVarintRoundTrip(-value);
+    for (OutputType outputType : OutputType.values()) {
+      assertVarintRoundTrip(outputType, 0L);
+      for (int bits = 0; bits < 64; bits++) {
+        long value = 1L << bits;
+        assertVarintRoundTrip(outputType, value);
+        assertVarintRoundTrip(outputType, value + 1);
+        assertVarintRoundTrip(outputType, value - 1);
+        assertVarintRoundTrip(outputType, -value);
+      }
     }
   }
 
@@ -173,70 +236,25 @@ public class CodedOutputStreamTest extends TestCase {
     // 14882
     assertWriteVarint(bytes(0xa2, 0x74), (0x22 << 0) | (0x74 << 7));
     // 2961488830
-    assertWriteVarint(bytes(0xbe, 0xf7, 0x92, 0x84, 0x0b),
-      (0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) |
-      (0x0bL << 28));
+    assertWriteVarint(
+        bytes(0xbe, 0xf7, 0x92, 0x84, 0x0b),
+        (0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) | (0x0bL << 28));
 
     // 64-bit
     // 7256456126
-    assertWriteVarint(bytes(0xbe, 0xf7, 0x92, 0x84, 0x1b),
-      (0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) |
-      (0x1bL << 28));
+    assertWriteVarint(
+        bytes(0xbe, 0xf7, 0x92, 0x84, 0x1b),
+        (0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) | (0x1bL << 28));
     // 41256202580718336
     assertWriteVarint(
-      bytes(0x80, 0xe6, 0xeb, 0x9c, 0xc3, 0xc9, 0xa4, 0x49),
-      (0x00 << 0) | (0x66 << 7) | (0x6b << 14) | (0x1c << 21) |
-      (0x43L << 28) | (0x49L << 35) | (0x24L << 42) | (0x49L << 49));
+        bytes(0x80, 0xe6, 0xeb, 0x9c, 0xc3, 0xc9, 0xa4, 0x49),
+        (0x00 << 0) | (0x66 << 7) | (0x6b << 14) | (0x1c << 21) | (0x43L << 28) | (0x49L << 35)
+        | (0x24L << 42) | (0x49L << 49));
     // 11964378330978735131
     assertWriteVarint(
-      bytes(0x9b, 0xa8, 0xf9, 0xc2, 0xbb, 0xd6, 0x80, 0x85, 0xa6, 0x01),
-      (0x1b << 0) | (0x28 << 7) | (0x79 << 14) | (0x42 << 21) |
-      (0x3bL << 28) | (0x56L << 35) | (0x00L << 42) |
-      (0x05L << 49) | (0x26L << 56) | (0x01L << 63));
-  }
-
-  /**
-   * Parses the given bytes using writeRawLittleEndian32() and checks
-   * that the result matches the given value.
-   */
-  private void assertWriteLittleEndian32(byte[] data, int value)
-                                         throws Exception {
-    ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-    CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-    output.writeRawLittleEndian32(value);
-    output.flush();
-    assertEqualBytes(data, rawOutput.toByteArray());
-
-    // Try different block sizes.
-    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
-      rawOutput = new ByteArrayOutputStream();
-      output = CodedOutputStream.newInstance(rawOutput, blockSize);
-      output.writeRawLittleEndian32(value);
-      output.flush();
-      assertEqualBytes(data, rawOutput.toByteArray());
-    }
-  }
-
-  /**
-   * Parses the given bytes using writeRawLittleEndian64() and checks
-   * that the result matches the given value.
-   */
-  private void assertWriteLittleEndian64(byte[] data, long value)
-                                         throws Exception {
-    ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-    CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-    output.writeRawLittleEndian64(value);
-    output.flush();
-    assertEqualBytes(data, rawOutput.toByteArray());
-
-    // Try different block sizes.
-    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
-      rawOutput = new ByteArrayOutputStream();
-      output = CodedOutputStream.newInstance(rawOutput, blockSize);
-      output.writeRawLittleEndian64(value);
-      output.flush();
-      assertEqualBytes(data, rawOutput.toByteArray());
-    }
+        bytes(0x9b, 0xa8, 0xf9, 0xc2, 0xbb, 0xd6, 0x80, 0x85, 0xa6, 0x01),
+        (0x1b << 0) | (0x28 << 7) | (0x79 << 14) | (0x42 << 21) | (0x3bL << 28) | (0x56L << 35)
+        | (0x00L << 42) | (0x05L << 49) | (0x26L << 56) | (0x01L << 63));
   }
 
   /** Tests writeRawLittleEndian32() and writeRawLittleEndian64(). */
@@ -245,141 +263,138 @@ public class CodedOutputStreamTest extends TestCase {
     assertWriteLittleEndian32(bytes(0xf0, 0xde, 0xbc, 0x9a), 0x9abcdef0);
 
     assertWriteLittleEndian64(
-      bytes(0xf0, 0xde, 0xbc, 0x9a, 0x78, 0x56, 0x34, 0x12),
-      0x123456789abcdef0L);
+        bytes(0xf0, 0xde, 0xbc, 0x9a, 0x78, 0x56, 0x34, 0x12), 0x123456789abcdef0L);
     assertWriteLittleEndian64(
-      bytes(0x78, 0x56, 0x34, 0x12, 0xf0, 0xde, 0xbc, 0x9a),
-      0x9abcdef012345678L);
+        bytes(0x78, 0x56, 0x34, 0x12, 0xf0, 0xde, 0xbc, 0x9a), 0x9abcdef012345678L);
   }
 
   /** Test encodeZigZag32() and encodeZigZag64(). */
   public void testEncodeZigZag() throws Exception {
-    assertEquals(0, CodedOutputStream.encodeZigZag32( 0));
+    assertEquals(0, CodedOutputStream.encodeZigZag32(0));
     assertEquals(1, CodedOutputStream.encodeZigZag32(-1));
-    assertEquals(2, CodedOutputStream.encodeZigZag32( 1));
+    assertEquals(2, CodedOutputStream.encodeZigZag32(1));
     assertEquals(3, CodedOutputStream.encodeZigZag32(-2));
     assertEquals(0x7FFFFFFE, CodedOutputStream.encodeZigZag32(0x3FFFFFFF));
     assertEquals(0x7FFFFFFF, CodedOutputStream.encodeZigZag32(0xC0000000));
     assertEquals(0xFFFFFFFE, CodedOutputStream.encodeZigZag32(0x7FFFFFFF));
     assertEquals(0xFFFFFFFF, CodedOutputStream.encodeZigZag32(0x80000000));
 
-    assertEquals(0, CodedOutputStream.encodeZigZag64( 0));
+    assertEquals(0, CodedOutputStream.encodeZigZag64(0));
     assertEquals(1, CodedOutputStream.encodeZigZag64(-1));
-    assertEquals(2, CodedOutputStream.encodeZigZag64( 1));
+    assertEquals(2, CodedOutputStream.encodeZigZag64(1));
     assertEquals(3, CodedOutputStream.encodeZigZag64(-2));
-    assertEquals(0x000000007FFFFFFEL,
-                 CodedOutputStream.encodeZigZag64(0x000000003FFFFFFFL));
-    assertEquals(0x000000007FFFFFFFL,
-                 CodedOutputStream.encodeZigZag64(0xFFFFFFFFC0000000L));
-    assertEquals(0x00000000FFFFFFFEL,
-                 CodedOutputStream.encodeZigZag64(0x000000007FFFFFFFL));
-    assertEquals(0x00000000FFFFFFFFL,
-                 CodedOutputStream.encodeZigZag64(0xFFFFFFFF80000000L));
-    assertEquals(0xFFFFFFFFFFFFFFFEL,
-                 CodedOutputStream.encodeZigZag64(0x7FFFFFFFFFFFFFFFL));
-    assertEquals(0xFFFFFFFFFFFFFFFFL,
-                 CodedOutputStream.encodeZigZag64(0x8000000000000000L));
+    assertEquals(0x000000007FFFFFFEL, CodedOutputStream.encodeZigZag64(0x000000003FFFFFFFL));
+    assertEquals(0x000000007FFFFFFFL, CodedOutputStream.encodeZigZag64(0xFFFFFFFFC0000000L));
+    assertEquals(0x00000000FFFFFFFEL, CodedOutputStream.encodeZigZag64(0x000000007FFFFFFFL));
+    assertEquals(0x00000000FFFFFFFFL, CodedOutputStream.encodeZigZag64(0xFFFFFFFF80000000L));
+    assertEquals(0xFFFFFFFFFFFFFFFEL, CodedOutputStream.encodeZigZag64(0x7FFFFFFFFFFFFFFFL));
+    assertEquals(0xFFFFFFFFFFFFFFFFL, CodedOutputStream.encodeZigZag64(0x8000000000000000L));
 
     // Some easier-to-verify round-trip tests.  The inputs (other than 0, 1, -1)
     // were chosen semi-randomly via keyboard bashing.
-    assertEquals(0,
-      CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(0)));
-    assertEquals(1,
-      CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(1)));
-    assertEquals(-1,
-      CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(-1)));
-    assertEquals(14927,
-      CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(14927)));
-    assertEquals(-3612,
-      CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(-3612)));
-
-    assertEquals(0,
-      CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(0)));
-    assertEquals(1,
-      CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(1)));
-    assertEquals(-1,
-      CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(-1)));
-    assertEquals(14927,
-      CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(14927)));
-    assertEquals(-3612,
-      CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(-3612)));
-
-    assertEquals(856912304801416L,
-      CodedOutputStream.encodeZigZag64(
-        CodedInputStream.decodeZigZag64(
-          856912304801416L)));
-    assertEquals(-75123905439571256L,
-      CodedOutputStream.encodeZigZag64(
-        CodedInputStream.decodeZigZag64(
-          -75123905439571256L)));
+    assertEquals(0, CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(0)));
+    assertEquals(1, CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(1)));
+    assertEquals(-1, CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(-1)));
+    assertEquals(14927, CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(14927)));
+    assertEquals(-3612, CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(-3612)));
+
+    assertEquals(0, CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(0)));
+    assertEquals(1, CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(1)));
+    assertEquals(-1, CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(-1)));
+    assertEquals(14927, CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(14927)));
+    assertEquals(-3612, CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(-3612)));
+
+    assertEquals(
+        856912304801416L,
+        CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(856912304801416L)));
+    assertEquals(
+        -75123905439571256L,
+        CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(-75123905439571256L)));
   }
 
   /** Tests writing a whole message with every field type. */
   public void testWriteWholeMessage() throws Exception {
+    final byte[] expectedBytes = TestUtil.getGoldenMessage().toByteArray();
     TestAllTypes message = TestUtil.getAllSet();
 
-    byte[] rawBytes = message.toByteArray();
-    assertEqualBytes(TestUtil.getGoldenMessage().toByteArray(), rawBytes);
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(message.getSerializedSize());
+      message.writeTo(coder.stream());
+      coder.stream().flush();
+      byte[] rawBytes = coder.toByteArray();
+      assertEqualBytes(outputType, expectedBytes, rawBytes);
+    }
 
     // Try different block sizes.
     for (int blockSize = 1; blockSize < 256; blockSize *= 2) {
-      ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-      CodedOutputStream output =
-        CodedOutputStream.newInstance(rawOutput, blockSize);
-      message.writeTo(output);
-      output.flush();
-      assertEqualBytes(rawBytes, rawOutput.toByteArray());
+      Coder coder = OutputType.STREAM.newCoder(blockSize);
+      message.writeTo(coder.stream());
+      coder.stream().flush();
+      assertEqualBytes(OutputType.STREAM, expectedBytes, coder.toByteArray());
     }
   }
 
-  /** Tests writing a whole message with every packed field type. Ensures the
-   * wire format of packed fields is compatible with C++. */
+  /**
+   * Tests writing a whole message with every packed field type. Ensures the
+   * wire format of packed fields is compatible with C++.
+   */
   public void testWriteWholePackedFieldsMessage() throws Exception {
+    byte[] expectedBytes = TestUtil.getGoldenPackedFieldsMessage().toByteArray();
     TestPackedTypes message = TestUtil.getPackedSet();
 
-    byte[] rawBytes = message.toByteArray();
-    assertEqualBytes(TestUtil.getGoldenPackedFieldsMessage().toByteArray(),
-                     rawBytes);
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(message.getSerializedSize());
+      message.writeTo(coder.stream());
+      coder.stream().flush();
+      byte[] rawBytes = coder.toByteArray();
+      assertEqualBytes(outputType, expectedBytes, rawBytes);
+    }
   }
 
-  /** Test writing a message containing a negative enum value. This used to
+  /**
+   * Test writing a message containing a negative enum value. This used to
    * fail because the size was not properly computed as a sign-extended varint.
    */
   public void testWriteMessageWithNegativeEnumValue() throws Exception {
-    SparseEnumMessage message = SparseEnumMessage.newBuilder()
-        .setSparseEnum(TestSparseEnum.SPARSE_E) .build();
+    SparseEnumMessage message =
+        SparseEnumMessage.newBuilder().setSparseEnum(TestSparseEnum.SPARSE_E).build();
     assertTrue(message.getSparseEnum().getNumber() < 0);
-    byte[] rawBytes = message.toByteArray();
-    SparseEnumMessage message2 = SparseEnumMessage.parseFrom(rawBytes);
-    assertEquals(TestSparseEnum.SPARSE_E, message2.getSparseEnum());
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(message.getSerializedSize());
+      message.writeTo(coder.stream());
+      coder.stream().flush();
+      byte[] rawBytes = coder.toByteArray();
+      SparseEnumMessage message2 = SparseEnumMessage.parseFrom(rawBytes);
+      assertEquals(TestSparseEnum.SPARSE_E, message2.getSparseEnum());
+    }
   }
 
   /** Test getTotalBytesWritten() */
   public void testGetTotalBytesWritten() throws Exception {
-    final int BUFFER_SIZE = 4 * 1024;
-    ByteArrayOutputStream outputStream = new ByteArrayOutputStream(BUFFER_SIZE);
-    CodedOutputStream codedStream = CodedOutputStream.newInstance(outputStream);
+    Coder coder = OutputType.STREAM.newCoder(4 * 1024);
+
+    // Write some some bytes (more than the buffer can hold) and verify that totalWritten
+    // is correct.
     byte[] value = "abcde".getBytes(Internal.UTF_8);
     for (int i = 0; i < 1024; ++i) {
-      codedStream.writeRawBytes(value, 0, value.length);
+      coder.stream().writeRawBytes(value, 0, value.length);
     }
+    assertEquals(value.length * 1024, coder.stream().getTotalBytesWritten());
+
+    // Now write an encoded string.
     String string =
         "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz";
     // Ensure we take the slower fast path.
-    assertTrue(CodedOutputStream.computeRawVarint32Size(string.length())
-        != CodedOutputStream.computeRawVarint32Size(string.length() * Utf8.MAX_BYTES_PER_CHAR));
-    
-    codedStream.writeStringNoTag(string);
+    assertTrue(CodedOutputStream.computeUInt32SizeNoTag(string.length())
+        != CodedOutputStream.computeUInt32SizeNoTag(string.length() * Utf8.MAX_BYTES_PER_CHAR));
+
+    coder.stream().writeStringNoTag(string);
     int stringSize = CodedOutputStream.computeStringSizeNoTag(string);
-    
-    // Make sure we have written more bytes than the buffer could hold. This is
-    // to make the test complete.
-    assertTrue(codedStream.getTotalBytesWritten() > BUFFER_SIZE);
-    
+
     // Verify that the total bytes written is correct
-    assertEquals((value.length * 1024) + stringSize, codedStream.getTotalBytesWritten());
+    assertEquals((value.length * 1024) + stringSize, coder.stream().getTotalBytesWritten());
   }
-  
+
   // TODO(dweis): Write a comprehensive test suite for CodedOutputStream that covers more than just
   //    this case.
   public void testWriteStringNoTag_fastpath() throws Exception {
@@ -390,14 +405,16 @@ public class CodedOutputStreamTest extends TestCase {
       string += threeBytesPer;
     }
     // These checks ensure we will tickle the slower fast path.
-    assertEquals(1, CodedOutputStream.computeRawVarint32Size(string.length()));
+    assertEquals(1, CodedOutputStream.computeUInt32SizeNoTag(string.length()));
     assertEquals(
-        2, CodedOutputStream.computeRawVarint32Size(string.length() * Utf8.MAX_BYTES_PER_CHAR));
+        2, CodedOutputStream.computeUInt32SizeNoTag(string.length() * Utf8.MAX_BYTES_PER_CHAR));
     assertEquals(bufferSize, string.length() * Utf8.MAX_BYTES_PER_CHAR);
-    
-    CodedOutputStream output =
-        CodedOutputStream.newInstance(ByteBuffer.allocate(bufferSize), bufferSize);
-    output.writeStringNoTag(string);
+
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(bufferSize + 2);
+      coder.stream().writeStringNoTag(string);
+      coder.stream().flush();
+    }
   }
 
   public void testWriteToByteBuffer() throws Exception {
@@ -464,83 +481,296 @@ public class CodedOutputStreamTest extends TestCase {
     byte[] destination = new byte[4];
     CodedOutputStream codedStream = CodedOutputStream.newInstance(destination);
     codedStream.writeByteArrayNoTag(fullArray, 2, 2);
-    assertEqualBytes(bytes(0x02, 0x33, 0x44, 0x00), destination);
+    assertEqualBytes(OutputType.ARRAY, bytes(0x02, 0x33, 0x44, 0x00), destination);
     assertEquals(3, codedStream.getTotalBytesWritten());
   }
-  
+
+  public void testSerializeUtf8_MultipleSmallWrites() throws Exception {
+    final String source = "abcdefghijklmnopqrstuvwxyz";
+
+    // Generate the expected output if the source string is written 2 bytes at a time.
+    ByteArrayOutputStream expectedBytesStream = new ByteArrayOutputStream();
+    for (int pos = 0; pos < source.length(); pos += 2) {
+      String substr = source.substring(pos, pos + 2);
+      expectedBytesStream.write(2);
+      expectedBytesStream.write(substr.getBytes(Internal.UTF_8));
+    }
+    final byte[] expectedBytes = expectedBytesStream.toByteArray();
+
+    // For each output type, write the source string 2 bytes at a time and verify the output.
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(expectedBytes.length);
+      for (int pos = 0; pos < source.length(); pos += 2) {
+        String substr = source.substring(pos, pos + 2);
+        coder.stream().writeStringNoTag(substr);
+      }
+      coder.stream().flush();
+      assertEqualBytes(outputType, expectedBytes, coder.toByteArray());
+    }
+  }
+
   public void testSerializeInvalidUtf8() throws Exception {
-    String[] invalidStrings = new String[] {
-        newString(Character.MIN_HIGH_SURROGATE),
-        "foobar" + newString(Character.MIN_HIGH_SURROGATE),
-        newString(Character.MIN_LOW_SURROGATE),
+    String[] invalidStrings = new String[] {newString(Character.MIN_HIGH_SURROGATE),
+        "foobar" + newString(Character.MIN_HIGH_SURROGATE), newString(Character.MIN_LOW_SURROGATE),
         "foobar" + newString(Character.MIN_LOW_SURROGATE),
-        newString(Character.MIN_HIGH_SURROGATE, Character.MIN_HIGH_SURROGATE)
-    };
-    
+        newString(Character.MIN_HIGH_SURROGATE, Character.MIN_HIGH_SURROGATE)};
+
     CodedOutputStream outputWithStream = CodedOutputStream.newInstance(new ByteArrayOutputStream());
     CodedOutputStream outputWithArray = CodedOutputStream.newInstance(new byte[10000]);
+    CodedOutputStream outputWithByteBuffer =
+        CodedOutputStream.newInstance(ByteBuffer.allocate(10000));
     for (String s : invalidStrings) {
       // TODO(dweis): These should all fail; instead they are corrupting data.
       CodedOutputStream.computeStringSizeNoTag(s);
       outputWithStream.writeStringNoTag(s);
       outputWithArray.writeStringNoTag(s);
+      outputWithByteBuffer.writeStringNoTag(s);
     }
   }
-  
-  private static String newString(char... chars) {
-    return new String(chars);
+
+  // TODO(nathanmittler): This test can be deleted once we properly throw IOException while
+  // encoding invalid UTF-8 strings.
+  public void testSerializeInvalidUtf8FollowedByOutOfSpace() throws Exception {
+    final int notEnoughBytes = 4;
+    CodedOutputStream outputWithArray = CodedOutputStream.newInstance(new byte[notEnoughBytes]);
+    CodedOutputStream outputWithByteBuffer =
+        CodedOutputStream.newInstance(ByteBuffer.allocate(notEnoughBytes));
+
+    String invalidString = newString(Character.MIN_HIGH_SURROGATE, 'f', 'o', 'o', 'b', 'a', 'r');
+    try {
+      outputWithArray.writeStringNoTag(invalidString);
+      fail("Expected OutOfSpaceException");
+    } catch (OutOfSpaceException e) {
+      assertTrue(e.getCause() instanceof IndexOutOfBoundsException);
+    }
+    try {
+      outputWithByteBuffer.writeStringNoTag(invalidString);
+      fail("Expected OutOfSpaceException");
+    } catch (OutOfSpaceException e) {
+      assertTrue(e.getCause() instanceof IndexOutOfBoundsException);
+    }
   }
 
   /** Regression test for https://github.com/google/protobuf/issues/292 */
   public void testCorrectExceptionThrowWhenEncodingStringsWithoutEnoughSpace() throws Exception {
     String testCase = "Foooooooo";
-    assertEquals(CodedOutputStream.computeRawVarint32Size(testCase.length()),
-        CodedOutputStream.computeRawVarint32Size(testCase.length() * 3));
+    assertEquals(
+        CodedOutputStream.computeUInt32SizeNoTag(testCase.length()),
+        CodedOutputStream.computeUInt32SizeNoTag(testCase.length() * 3));
     assertEquals(11, CodedOutputStream.computeStringSize(1, testCase));
     // Tag is one byte, varint describing string length is 1 byte, string length is 9 bytes.
     // An array of size 1 will cause a failure when trying to write the varint.
-    for (int i = 0; i < 11; i++) {
-      CodedOutputStream output = CodedOutputStream.newInstance(new byte[i]);
-      try {
-        output.writeString(1, testCase);
-        fail("Should have thrown an out of space exception");
-      } catch (CodedOutputStream.OutOfSpaceException expected) {}
+    for (OutputType outputType :
+        new OutputType[] {OutputType.ARRAY, OutputType.NIO_HEAP, OutputType.NIO_DIRECT}) {
+      for (int i = 0; i < 11; i++) {
+        Coder coder = outputType.newCoder(i);
+        try {
+          coder.stream().writeString(1, testCase);
+          fail("Should have thrown an out of space exception");
+        } catch (CodedOutputStream.OutOfSpaceException expected) {
+        }
+      }
     }
   }
-  
+
   public void testDifferentStringLengths() throws Exception {
     // Test string serialization roundtrip using strings of the following lengths,
     // with ASCII and Unicode characters requiring different UTF-8 byte counts per
     // char, hence causing the length delimiter varint to sometimes require more
     // bytes for the Unicode strings than the ASCII string of the same length.
     int[] lengths = new int[] {
-            0,
-            1,
-            (1 << 4) - 1,  // 1 byte for ASCII and Unicode
-            (1 << 7) - 1,  // 1 byte for ASCII, 2 bytes for Unicode
-            (1 << 11) - 1, // 2 bytes for ASCII and Unicode
-            (1 << 14) - 1, // 2 bytes for ASCII, 3 bytes for Unicode
-            (1 << 17) - 1, // 3 bytes for ASCII and Unicode
+        0,
+        1,
+        (1 << 4) - 1, // 1 byte for ASCII and Unicode
+        (1 << 7) - 1, // 1 byte for ASCII, 2 bytes for Unicode
+        (1 << 11) - 1, // 2 bytes for ASCII and Unicode
+        (1 << 14) - 1, // 2 bytes for ASCII, 3 bytes for Unicode
+        (1 << 17) - 1,
+        // 3 bytes for ASCII and Unicode
     };
-    for (int i : lengths) {
-      testEncodingOfString('q', i);      // 1 byte per char
-      testEncodingOfString('\u07FF', i); // 2 bytes per char
-      testEncodingOfString('\u0981', i); // 3 bytes per char
+    for (OutputType outputType : OutputType.values()) {
+      for (int i : lengths) {
+        testEncodingOfString(outputType, 'q', i); // 1 byte per char
+        testEncodingOfString(outputType, '\u07FF', i); // 2 bytes per char
+        testEncodingOfString(outputType, '\u0981', i); // 3 bytes per char
+      }
     }
   }
 
-  private void testEncodingOfString(char c, int length) throws Exception {
+  public void testNioEncodersWithInitialOffsets() throws Exception {
+    String value = "abc";
+    for (Coder coder : new Coder[] {new NioHeapCoder(10, 2), new NioDirectCoder(10, 2)}) {
+      coder.stream().writeStringNoTag(value);
+      coder.stream().flush();
+      assertEqualBytes(coder.getOutputType(), new byte[]{3, 'a', 'b', 'c'}, coder.toByteArray());
+    }
+  }
+
+  /**
+   * Parses the given bytes using writeRawLittleEndian32() and checks
+   * that the result matches the given value.
+   */
+  private static void assertWriteLittleEndian32(byte[] data, int value) throws Exception {
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(data.length);
+      coder.stream().writeFixed32NoTag(value);
+      coder.stream().flush();
+      assertEqualBytes(outputType, data, coder.toByteArray());
+    }
+
+    // Try different block sizes.
+    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
+      Coder coder = OutputType.STREAM.newCoder(blockSize);
+      coder.stream().writeFixed32NoTag(value);
+      coder.stream().flush();
+      assertEqualBytes(OutputType.STREAM, data, coder.toByteArray());
+    }
+  }
+
+  /**
+   * Parses the given bytes using writeRawLittleEndian64() and checks
+   * that the result matches the given value.
+   */
+  private static void assertWriteLittleEndian64(byte[] data, long value) throws Exception {
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(data.length);
+      coder.stream().writeFixed64NoTag(value);
+      coder.stream().flush();
+      assertEqualBytes(outputType, data, coder.toByteArray());
+    }
+
+    // Try different block sizes.
+    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
+      Coder coder = OutputType.STREAM.newCoder(blockSize);
+      coder.stream().writeFixed64NoTag(value);
+      coder.stream().flush();
+      assertEqualBytes(OutputType.STREAM, data, coder.toByteArray());
+    }
+  }
+
+  private static String newString(char... chars) {
+    return new String(chars);
+  }
+
+  private static void testEncodingOfString(OutputType outputType, char c, int length)
+      throws Exception {
     String fullString = fullString(c, length);
-    TestAllTypes testAllTypes = TestAllTypes.newBuilder()
-        .setOptionalString(fullString)
-        .build();
+    TestAllTypes testAllTypes = TestAllTypes.newBuilder().setOptionalString(fullString).build();
+    Coder coder = outputType.newCoder(testAllTypes.getSerializedSize());
+    testAllTypes.writeTo(coder.stream());
+    coder.stream().flush();
     assertEquals(
-        fullString, TestAllTypes.parseFrom(testAllTypes.toByteArray()).getOptionalString());
+        "OuputType: " + outputType,
+        fullString,
+        TestAllTypes.parseFrom(coder.toByteArray()).getOptionalString());
   }
 
-  private String fullString(char c, int length) {
+  private static String fullString(char c, int length) {
     char[] result = new char[length];
     Arrays.fill(result, c);
     return new String(result);
   }
+
+  /**
+   * Helper to construct a byte array from a bunch of bytes.  The inputs are
+   * actually ints so that I can use hex notation and not get stupid errors
+   * about precision.
+   */
+  private static byte[] bytes(int... bytesAsInts) {
+    byte[] bytes = new byte[bytesAsInts.length];
+    for (int i = 0; i < bytesAsInts.length; i++) {
+      bytes[i] = (byte) bytesAsInts[i];
+    }
+    return bytes;
+  }
+
+  /** Arrays.asList() does not work with arrays of primitives.  :( */
+  private static List<Byte> toList(byte[] bytes) {
+    List<Byte> result = new ArrayList<Byte>();
+    for (byte b : bytes) {
+      result.add(b);
+    }
+    return result;
+  }
+
+  private static void assertEqualBytes(OutputType outputType, byte[] a, byte[] b) {
+    assertEquals(outputType.name(), toList(a), toList(b));
+  }
+
+  /**
+   * Writes the given value using writeRawVarint32() and writeRawVarint64() and
+   * checks that the result matches the given bytes.
+   */
+  private static void assertWriteVarint(byte[] data, long value) throws Exception {
+    for (OutputType outputType : OutputType.values()) {
+      // Only test 32-bit write if the value fits into an int.
+      if (value == (int) value) {
+        Coder coder = outputType.newCoder(10);
+        coder.stream().writeUInt32NoTag((int) value);
+        coder.stream().flush();
+        assertEqualBytes(outputType, data, coder.toByteArray());
+
+        // Also try computing size.
+        assertEquals(data.length, CodedOutputStream.computeUInt32SizeNoTag((int) value));
+      }
+
+      {
+        Coder coder = outputType.newCoder(10);
+        coder.stream().writeUInt64NoTag(value);
+        coder.stream().flush();
+        assertEqualBytes(outputType, data, coder.toByteArray());
+
+        // Also try computing size.
+        assertEquals(data.length, CodedOutputStream.computeUInt64SizeNoTag(value));
+      }
+    }
+
+    // Try different block sizes.
+    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
+      // Only test 32-bit write if the value fits into an int.
+      if (value == (int) value) {
+        Coder coder = OutputType.STREAM.newCoder(blockSize);
+        coder.stream().writeUInt64NoTag((int) value);
+        coder.stream().flush();
+        assertEqualBytes(OutputType.STREAM, data, coder.toByteArray());
+
+        ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
+        CodedOutputStream output = CodedOutputStream.newInstance(rawOutput, blockSize);
+        output.writeUInt32NoTag((int) value);
+        output.flush();
+        assertEqualBytes(OutputType.STREAM, data, rawOutput.toByteArray());
+      }
+
+      {
+        Coder coder = OutputType.STREAM.newCoder(blockSize);
+        coder.stream().writeUInt64NoTag(value);
+        coder.stream().flush();
+        assertEqualBytes(OutputType.STREAM, data, coder.toByteArray());
+      }
+    }
+  }
+
+  private static void assertVarintRoundTrip(OutputType outputType, long value) throws Exception {
+    {
+      Coder coder = outputType.newCoder(10);
+      coder.stream().writeUInt64NoTag(value);
+      coder.stream().flush();
+      byte[] bytes = coder.toByteArray();
+      assertEquals(
+          outputType.name(), bytes.length, CodedOutputStream.computeUInt64SizeNoTag(value));
+      CodedInputStream input = CodedInputStream.newInstance(new ByteArrayInputStream(bytes));
+      assertEquals(outputType.name(), value, input.readRawVarint64());
+    }
+
+    if (value == (int) value) {
+      Coder coder = outputType.newCoder(10);
+      coder.stream().writeUInt32NoTag((int) value);
+      coder.stream().flush();
+      byte[] bytes = coder.toByteArray();
+      assertEquals(
+          outputType.name(), bytes.length, CodedOutputStream.computeUInt32SizeNoTag((int) value));
+      CodedInputStream input = CodedInputStream.newInstance(new ByteArrayInputStream(bytes));
+      assertEquals(outputType.name(), value, input.readRawVarint32());
+    }
+  }
 }
diff --git a/java/core/src/test/java/com/google/protobuf/DoubleArrayListTest.java b/java/core/src/test/java/com/google/protobuf/DoubleArrayListTest.java
index d3deaa07..85b418c4 100644
--- a/java/core/src/test/java/com/google/protobuf/DoubleArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/DoubleArrayListTest.java
@@ -73,20 +73,6 @@ public class DoubleArrayListTest extends TestCase {
     assertImmutable(list);
   }
   
-  public void testCopyConstructor() {
-    DoubleArrayList copy = new DoubleArrayList(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new DoubleArrayList(DoubleArrayList.emptyList());
-    assertEquals(DoubleArrayList.emptyList(), copy);
-    
-    copy = new DoubleArrayList(asList(1D, 2D, 3D));
-    assertEquals(asList(1D, 2D, 3D), copy);
-
-    copy = new DoubleArrayList(Collections.<Double>emptyList());
-    assertEquals(DoubleArrayList.emptyList(), copy);
-  }
-  
   public void testModificationWithIteration() {
     list.addAll(asList(1D, 2D, 3D, 4D));
     Iterator<Double> iterator = list.iterator();
diff --git a/java/core/src/test/java/com/google/protobuf/FloatArrayListTest.java b/java/core/src/test/java/com/google/protobuf/FloatArrayListTest.java
index a5e65424..88a75743 100644
--- a/java/core/src/test/java/com/google/protobuf/FloatArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/FloatArrayListTest.java
@@ -73,20 +73,6 @@ public class FloatArrayListTest extends TestCase {
     assertImmutable(list);
   }
   
-  public void testCopyConstructor() {
-    FloatArrayList copy = new FloatArrayList(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new FloatArrayList(FloatArrayList.emptyList());
-    assertEquals(FloatArrayList.emptyList(), copy);
-    
-    copy = new FloatArrayList(asList(1F, 2F, 3F));
-    assertEquals(asList(1F, 2F, 3F), copy);
-
-    copy = new FloatArrayList(Collections.<Float>emptyList());
-    assertEquals(FloatArrayList.emptyList(), copy);
-  }
-  
   public void testModificationWithIteration() {
     list.addAll(asList(1F, 2F, 3F, 4F));
     Iterator<Float> iterator = list.iterator();
diff --git a/java/core/src/test/java/com/google/protobuf/ForceFieldBuildersPreRun.java b/java/core/src/test/java/com/google/protobuf/ForceFieldBuildersPreRun.java
index a92ba374..b7eaebf5 100644
--- a/java/core/src/test/java/com/google/protobuf/ForceFieldBuildersPreRun.java
+++ b/java/core/src/test/java/com/google/protobuf/ForceFieldBuildersPreRun.java
@@ -41,7 +41,7 @@ package com.google.protobuf;
  */
 public class ForceFieldBuildersPreRun implements Runnable {
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void run() {
     GeneratedMessage.enableAlwaysUseFieldBuildersForTesting();
   }
diff --git a/java/core/src/test/java/com/google/protobuf/GeneratedMessageTest.java b/java/core/src/test/java/com/google/protobuf/GeneratedMessageTest.java
index 8cd1f38d..a9b8b638 100644
--- a/java/core/src/test/java/com/google/protobuf/GeneratedMessageTest.java
+++ b/java/core/src/test/java/com/google/protobuf/GeneratedMessageTest.java
@@ -723,7 +723,7 @@ public class GeneratedMessageTest extends TestCase {
 
   public void testLiteExtensionMessageOrBuilder() throws Exception {
     TestAllExtensionsLite.Builder builder = TestAllExtensionsLite.newBuilder();
-    TestUtil.setAllExtensions(builder);
+    TestUtilLite.setAllExtensions(builder);
     TestUtil.assertAllExtensionsSet(builder);
 
     TestAllExtensionsLite message = builder.build();
@@ -732,8 +732,8 @@ public class GeneratedMessageTest extends TestCase {
 
   public void testLiteExtensionRepeatedSetters() throws Exception {
     TestAllExtensionsLite.Builder builder = TestAllExtensionsLite.newBuilder();
-    TestUtil.setAllExtensions(builder);
-    TestUtil.modifyRepeatedExtensions(builder);
+    TestUtilLite.setAllExtensions(builder);
+    TestUtilLite.modifyRepeatedExtensions(builder);
     TestUtil.assertRepeatedExtensionsModified(builder);
 
     TestAllExtensionsLite message = builder.build();
@@ -760,7 +760,7 @@ public class GeneratedMessageTest extends TestCase {
   }
 
   public void testLiteExtensionCopy() throws Exception {
-    TestAllExtensionsLite original = TestUtil.getAllLiteExtensionsSet();
+    TestAllExtensionsLite original = TestUtilLite.getAllLiteExtensionsSet();
     TestAllExtensionsLite copy =
         TestAllExtensionsLite.newBuilder(original).build();
     TestUtil.assertAllExtensionsSet(copy);
diff --git a/java/core/src/test/java/com/google/protobuf/IntArrayListTest.java b/java/core/src/test/java/com/google/protobuf/IntArrayListTest.java
index 3733eb30..efb8f3e2 100644
--- a/java/core/src/test/java/com/google/protobuf/IntArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/IntArrayListTest.java
@@ -72,20 +72,6 @@ public class IntArrayListTest extends TestCase {
     list.makeImmutable();
     assertImmutable(list);
   }
-  
-  public void testCopyConstructor() {
-    IntArrayList copy = new IntArrayList(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new IntArrayList(IntArrayList.emptyList());
-    assertEquals(IntArrayList.emptyList(), copy);
-    
-    copy = new IntArrayList(asList(1, 2, 3));
-    assertEquals(asList(1, 2, 3), copy);
-
-    copy = new IntArrayList(Collections.<Integer>emptyList());
-    assertEquals(IntArrayList.emptyList(), copy);
-  }
 
   public void testModificationWithIteration() {
     list.addAll(asList(1, 2, 3, 4));
diff --git a/java/core/src/test/java/com/google/protobuf/LiteTest.java b/java/core/src/test/java/com/google/protobuf/LiteTest.java
index 9e503cc3..88c3e0b2 100644
--- a/java/core/src/test/java/com/google/protobuf/LiteTest.java
+++ b/java/core/src/test/java/com/google/protobuf/LiteTest.java
@@ -33,17 +33,25 @@ package com.google.protobuf;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 
+import com.google.protobuf.UnittestImportLite.ImportEnumLite;
+import com.google.protobuf.UnittestImportPublicLite.PublicImportMessageLite;
 import com.google.protobuf.UnittestLite;
 import com.google.protobuf.UnittestLite.ForeignEnumLite;
 import com.google.protobuf.UnittestLite.ForeignMessageLite;
 import com.google.protobuf.UnittestLite.TestAllExtensionsLite;
 import com.google.protobuf.UnittestLite.TestAllTypesLite;
+import com.google.protobuf.UnittestLite.TestAllTypesLite.NestedEnum;
 import com.google.protobuf.UnittestLite.TestAllTypesLite.NestedMessage;
 import com.google.protobuf.UnittestLite.TestAllTypesLite.OneofFieldCase;
 import com.google.protobuf.UnittestLite.TestAllTypesLite.OptionalGroup;
 import com.google.protobuf.UnittestLite.TestAllTypesLite.RepeatedGroup;
 import com.google.protobuf.UnittestLite.TestAllTypesLiteOrBuilder;
 import com.google.protobuf.UnittestLite.TestNestedExtensionLite;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.Bar;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.BarPrime;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.Foo;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.TestOneofEquals;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.TestRecursiveOneof;
 
 import junit.framework.TestCase;
 
@@ -59,6 +67,7 @@ import java.io.ObjectOutputStream;
  * @author kenton@google.com Kenton Varda
  */
 public class LiteTest extends TestCase {
+  @Override
   public void setUp() throws Exception {
     // Test that nested extensions are initialized correctly even if the outer
     // class has not been accessed directly.  This was once a bug with lite
@@ -302,11 +311,9 @@ public class LiteTest extends TestCase {
     assertEquals(
         ForeignMessageLite.getDefaultInstance(),
         message.getOptionalForeignMessage());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on foreignMessage.
-    assertEquals(3, builder.getOptionalForeignMessage().getC());
+    assertEquals(foreignMessageBuilder.build(), builder.getOptionalForeignMessage());
     messageAfterBuild = builder.build();
-    assertEquals(3, messageAfterBuild.getOptionalForeignMessage().getC());
+    assertEquals(foreignMessageBuilder.build(), messageAfterBuild.getOptionalForeignMessage());
     assertEquals(
         ForeignMessageLite.getDefaultInstance(),
         message.getOptionalForeignMessage());
@@ -314,7 +321,7 @@ public class LiteTest extends TestCase {
     assertEquals(
         ForeignMessageLite.getDefaultInstance(),
         builder.getOptionalForeignMessage());
-    assertEquals(3, messageAfterBuild.getOptionalForeignMessage().getC());
+    assertEquals(foreignMessageBuilder.build(), messageAfterBuild.getOptionalForeignMessage());
 
     message = builder.build();
     OptionalGroup optionalGroup = OptionalGroup.newBuilder()
@@ -339,17 +346,15 @@ public class LiteTest extends TestCase {
     builder.setOptionalGroup(optionalGroupBuilder);
     assertEquals(
         OptionalGroup.getDefaultInstance(), message.getOptionalGroup());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on optionalGroup.
-    assertEquals(3, builder.getOptionalGroup().getA());
+    assertEquals(optionalGroupBuilder.build(), builder.getOptionalGroup());
     messageAfterBuild = builder.build();
-    assertEquals(3, messageAfterBuild.getOptionalGroup().getA());
+    assertEquals(optionalGroupBuilder.build(), messageAfterBuild.getOptionalGroup());
     assertEquals(
         OptionalGroup.getDefaultInstance(), message.getOptionalGroup());
     builder.clearOptionalGroup();
     assertEquals(
         OptionalGroup.getDefaultInstance(), builder.getOptionalGroup());
-    assertEquals(3, messageAfterBuild.getOptionalGroup().getA());
+    assertEquals(optionalGroupBuilder.build(), messageAfterBuild.getOptionalGroup());
 
     message = builder.build();
     builder.setOptionalInt32(1);
@@ -400,17 +405,16 @@ public class LiteTest extends TestCase {
     assertEquals(
         NestedMessage.getDefaultInstance(),
         message.getOptionalLazyMessage());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property.
-    assertEquals(3, builder.getOptionalLazyMessage().getBb());
+    assertEquals(nestedMessageBuilder.build(), builder.getOptionalLazyMessage());
     messageAfterBuild = builder.build();
-    assertEquals(3, messageAfterBuild.getOptionalLazyMessage().getBb());
+    assertEquals(nestedMessageBuilder.build(), messageAfterBuild.getOptionalLazyMessage());
     assertEquals(
         NestedMessage.getDefaultInstance(),
         message.getOptionalLazyMessage());
     builder.clearOptionalLazyMessage();
     assertEquals(
         NestedMessage.getDefaultInstance(), builder.getOptionalLazyMessage());
-    assertEquals(3, messageAfterBuild.getOptionalLazyMessage().getBb());
+    assertEquals(nestedMessageBuilder.build(), messageAfterBuild.getOptionalLazyMessage());
 
     message = builder.build();
     builder.setOptionalSfixed32(1);
@@ -1100,8 +1104,7 @@ public class LiteTest extends TestCase {
     assertEquals(0, message.getRepeatedForeignMessageCount());
     builder.setRepeatedForeignMessage(
         0, ForeignMessageLite.getDefaultInstance());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property.
-    assertEquals(3, messageAfterBuild.getRepeatedForeignMessage(0).getC());
+    assertEquals(foreignMessageBuilder.build(), messageAfterBuild.getRepeatedForeignMessage(0));
     assertEquals(
         ForeignMessageLite.getDefaultInstance(),
         builder.getRepeatedForeignMessage(0));
@@ -1114,8 +1117,7 @@ public class LiteTest extends TestCase {
     builder.setRepeatedForeignMessage(0, foreignMessageBuilder);
     assertEquals(
         foreignMessage, messageAfterBuild.getRepeatedForeignMessage(0));
-    // LITE_RUNTIME doesn't implement equals so we compare on a property.
-    assertEquals(3, builder.getRepeatedForeignMessage(0).getC());
+    assertEquals(foreignMessageBuilder.build(), builder.getRepeatedForeignMessage(0));
     builder.clearRepeatedForeignMessage();
 
     message = builder.build();
@@ -1148,9 +1150,7 @@ public class LiteTest extends TestCase {
     messageAfterBuild = builder.build();
     assertEquals(0, message.getRepeatedGroupCount());
     builder.setRepeatedGroup(0, RepeatedGroup.getDefaultInstance());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on repeatedGroup.
-    assertEquals(3, messageAfterBuild.getRepeatedGroup(0).getA());
+    assertEquals(repeatedGroupBuilder.build(), messageAfterBuild.getRepeatedGroup(0));
     assertEquals(
         RepeatedGroup.getDefaultInstance(), builder.getRepeatedGroup(0));
     builder.clearRepeatedGroup();
@@ -1160,9 +1160,7 @@ public class LiteTest extends TestCase {
     messageAfterBuild = builder.build();
     assertEquals(0, message.getRepeatedGroupCount());
     builder.setRepeatedGroup(0, RepeatedGroup.getDefaultInstance());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on repeatedGroup.
-    assertEquals(3, messageAfterBuild.getRepeatedGroup(0).getA());
+    assertEquals(repeatedGroupBuilder.build(), messageAfterBuild.getRepeatedGroup(0));
     assertEquals(
         RepeatedGroup.getDefaultInstance(), builder.getRepeatedGroup(0));
     builder.clearRepeatedGroup();
@@ -1210,9 +1208,7 @@ public class LiteTest extends TestCase {
     messageAfterBuild = builder.build();
     assertEquals(0, message.getRepeatedLazyMessageCount());
     builder.setRepeatedLazyMessage(0, NestedMessage.getDefaultInstance());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on repeatedGroup.
-    assertEquals(3, messageAfterBuild.getRepeatedLazyMessage(0).getBb());
+    assertEquals(nestedMessageBuilder.build(), messageAfterBuild.getRepeatedLazyMessage(0));
     assertEquals(
         NestedMessage.getDefaultInstance(), builder.getRepeatedLazyMessage(0));
     builder.clearRepeatedLazyMessage();
@@ -1222,9 +1218,7 @@ public class LiteTest extends TestCase {
     messageAfterBuild = builder.build();
     assertEquals(0, message.getRepeatedLazyMessageCount());
     builder.setRepeatedLazyMessage(0, NestedMessage.getDefaultInstance());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on repeatedGroup.
-    assertEquals(3, messageAfterBuild.getRepeatedLazyMessage(0).getBb());
+    assertEquals(nestedMessageBuilder.build(), messageAfterBuild.getRepeatedLazyMessage(0));
     assertEquals(
         NestedMessage.getDefaultInstance(), builder.getRepeatedLazyMessage(0));
     builder.clearRepeatedLazyMessage();
@@ -1456,7 +1450,7 @@ public class LiteTest extends TestCase {
         .setOptionalFloat(2.72f)
         .setOptionalDouble(3.14)
         .build();
-    assertToStringEquals("optional_float: 2.72\noptional_double: 3.14", proto);
+    assertToStringEquals("optional_double: 3.14\noptional_float: 2.72", proto);
   }
 
   public void testToStringStringFields() throws Exception {
@@ -1511,7 +1505,7 @@ public class LiteTest extends TestCase {
             .setC(3))
         .build();
     assertToStringEquals(
-        "optional_foreign_message {\n  c: 3\n}\noptional_foreign_enum: FOREIGN_LITE_BAR",
+        "optional_foreign_enum: FOREIGN_LITE_BAR\noptional_foreign_message {\n  c: 3\n}",
         proto);
   }
 
@@ -1546,6 +1540,27 @@ public class LiteTest extends TestCase {
         "1: 123\n18: \"\\b\\a\"\n21: 3\n44: \"spam\"\n44: \"eggs\"",
         messageWithUnknownFields);
   }
+  
+  public void testToStringLazyMessage() throws Exception {
+    TestAllTypesLite message = TestAllTypesLite.newBuilder()
+        .setOptionalLazyMessage(NestedMessage.newBuilder().setBb(1).build())
+        .build();
+    assertToStringEquals("optional_lazy_message {\n  bb: 1\n}", message);
+  }
+  
+  public void testToStringGroup() throws Exception {
+    TestAllTypesLite message = TestAllTypesLite.newBuilder()
+        .setOptionalGroup(OptionalGroup.newBuilder().setA(1).build())
+        .build();
+    assertToStringEquals("optional_group {\n  a: 1\n}", message);
+  }
+  
+  public void testToStringOneof() throws Exception {
+    TestAllTypesLite message = TestAllTypesLite.newBuilder()
+        .setOneofString("hello")
+        .build();
+    assertToStringEquals("oneof_string: \"hello\"", message);
+  }
 
   // Asserts that the toString() representation of the message matches the expected. This verifies
   // the first line starts with a comment; but, does not factor in said comment as part of the
@@ -1598,4 +1613,617 @@ public class LiteTest extends TestCase {
     assertEquals(11, message.getOneofLazyNestedMessage().getBb());
     assertEquals(22L, message.getOneofLazyNestedMessage().getCc());
   }
+
+  public void testMergeFromStream_repeatedField() throws Exception {
+    TestAllTypesLite.Builder builder = TestAllTypesLite.newBuilder()
+        .addRepeatedString("hello");
+    builder.mergeFrom(CodedInputStream.newInstance(builder.build().toByteArray()));
+
+    assertEquals(2, builder.getRepeatedStringCount());
+  }
+
+  public void testMergeFromStream_invalidBytes() throws Exception {
+    TestAllTypesLite.Builder builder = TestAllTypesLite.newBuilder()
+        .setDefaultBool(true);
+    try {
+      builder.mergeFrom(CodedInputStream.newInstance("Invalid bytes".getBytes(Internal.UTF_8)));
+      fail();
+    } catch (InvalidProtocolBufferException expected) {}
+  }
+  
+  public void testMergeFrom_sanity() throws Exception {
+    TestAllTypesLite one = TestUtilLite.getAllLiteSetBuilder().build();
+    byte[] bytes = one.toByteArray();
+    TestAllTypesLite two = TestAllTypesLite.parseFrom(bytes);
+    
+    one = one.toBuilder().mergeFrom(one).build();
+    two = two.toBuilder().mergeFrom(bytes).build();
+    assertEquals(one, two);
+    assertEquals(two, one);
+    assertEquals(one.hashCode(), two.hashCode());
+  }
+  
+  public void testEquals_notEqual() throws Exception {
+    TestAllTypesLite one = TestUtilLite.getAllLiteSetBuilder().build();
+    byte[] bytes = one.toByteArray();
+    TestAllTypesLite two = one.toBuilder().mergeFrom(one).mergeFrom(bytes).build();
+    
+    assertFalse(one.equals(two));
+    assertFalse(two.equals(one));
+    
+    assertFalse(one.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(one));
+    
+    TestAllTypesLite oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultBool(true)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultCord("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultCordBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultDouble(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultFixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultFixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultFloat(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultImportEnum(ImportEnumLite.IMPORT_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultInt32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultInt64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultNestedEnum(NestedEnum.BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultSfixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultSfixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultSint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultSint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultString("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultStringBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultStringPiece("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultStringPieceBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultUint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultUint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedBool(true)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedCord("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedCordBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedDouble(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedFixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedFixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedFloat(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedImportEnum(ImportEnumLite.IMPORT_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedInt32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedInt64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedNestedEnum(NestedEnum.BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedSfixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedSfixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedSint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedSint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedString("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedStringBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedStringPiece("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedStringPieceBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedUint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedUint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalBool(true)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalCord("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalCordBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalDouble(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalFixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalFixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalFloat(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalImportEnum(ImportEnumLite.IMPORT_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalInt32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalInt64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalNestedEnum(NestedEnum.BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalSfixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalSfixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalSint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalSint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalString("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalStringBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalStringPiece("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalStringPieceBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalUint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalUint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofLazyNestedMessage(NestedMessage.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofNestedMessage(NestedMessage.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofString("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofStringBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofUint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalForeignMessage(ForeignMessageLite.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalGroup(OptionalGroup.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalPublicImportMessage(PublicImportMessageLite.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalLazyMessage(NestedMessage.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedLazyMessage(NestedMessage.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+  }
+
+  public void testEquals() throws Exception {
+    // Check that two identical objs are equal.
+    Foo foo1a = Foo.newBuilder()
+        .setValue(1)
+        .addBar(Bar.newBuilder().setName("foo1"))
+        .build();
+    Foo foo1b = Foo.newBuilder()
+        .setValue(1)
+        .addBar(Bar.newBuilder().setName("foo1"))
+        .build();
+    Foo foo2 = Foo.newBuilder()
+        .setValue(1)
+        .addBar(Bar.newBuilder().setName("foo2"))
+        .build();
+
+    // Check that equals is doing value rather than object equality.
+    assertEquals(foo1a, foo1b);
+    assertEquals(foo1a.hashCode(), foo1b.hashCode());
+
+    // Check that a diffeent object is not equal.
+    assertFalse(foo1a.equals(foo2));
+
+    // Check that two objects which have different types but the same field values are not
+    // considered to be equal.
+    Bar bar = Bar.newBuilder().setName("bar").build();
+    BarPrime barPrime = BarPrime.newBuilder().setName("bar").build();
+    assertFalse(bar.equals(barPrime));
+  }
+
+  public void testOneofEquals() throws Exception {
+    TestOneofEquals.Builder builder = TestOneofEquals.newBuilder();
+    TestOneofEquals message1 = builder.build();
+    // Set message2's name field to default value. The two messages should be different when we
+    // check with the oneof case.
+    builder.setName("");
+    TestOneofEquals message2 = builder.build();
+    assertFalse(message1.equals(message2));
+  }
+  
+  public void testEquals_sanity() throws Exception {
+    TestAllTypesLite one = TestUtilLite.getAllLiteSetBuilder().build();
+    TestAllTypesLite two = TestAllTypesLite.parseFrom(one.toByteArray());
+    assertEquals(one, two);
+    assertEquals(one.hashCode(), two.hashCode());
+    
+    assertEquals(
+        one.toBuilder().mergeFrom(two).build(),
+        two.toBuilder().mergeFrom(two.toByteArray()).build());
+  }
+
+  public void testEqualsAndHashCodeWithUnknownFields() throws InvalidProtocolBufferException {
+    Foo fooWithOnlyValue = Foo.newBuilder()
+        .setValue(1)
+        .build();
+
+    Foo fooWithValueAndExtension = fooWithOnlyValue.toBuilder()
+        .setValue(1)
+        .setExtension(Bar.fooExt, Bar.newBuilder()
+            .setName("name")
+            .build())
+        .build();
+
+    Foo fooWithValueAndUnknownFields = Foo.parseFrom(fooWithValueAndExtension.toByteArray());
+
+    assertEqualsAndHashCodeAreFalse(fooWithOnlyValue, fooWithValueAndUnknownFields);
+    assertEqualsAndHashCodeAreFalse(fooWithValueAndExtension, fooWithValueAndUnknownFields);
+  }
+  
+  // Test to ensure we avoid a class cast exception with oneofs.
+  public void testEquals_oneOfMessages() {
+    TestAllTypesLite mine = TestAllTypesLite.newBuilder()
+        .setOneofString("Hello")
+        .build();
+    
+    TestAllTypesLite other = TestAllTypesLite.newBuilder()
+        .setOneofNestedMessage(NestedMessage.getDefaultInstance())
+        .build();
+    
+    assertFalse(mine.equals(other));
+    assertFalse(other.equals(mine));
+  }
+
+  private void assertEqualsAndHashCodeAreFalse(Object o1, Object o2) {
+    assertFalse(o1.equals(o2));
+    assertFalse(o1.hashCode() == o2.hashCode());
+  }
+
+  public void testRecursiveHashcode() {
+    // This tests that we don't infinite loop.
+    TestRecursiveOneof.getDefaultInstance().hashCode();
+  }
 }
diff --git a/java/core/src/test/java/com/google/protobuf/LongArrayListTest.java b/java/core/src/test/java/com/google/protobuf/LongArrayListTest.java
index 1bd094f7..0a8f9ed2 100644
--- a/java/core/src/test/java/com/google/protobuf/LongArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/LongArrayListTest.java
@@ -73,20 +73,6 @@ public class LongArrayListTest extends TestCase {
     assertImmutable(list);
   }
   
-  public void testCopyConstructor() {
-    LongArrayList copy = new LongArrayList(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new LongArrayList(LongArrayList.emptyList());
-    assertEquals(LongArrayList.emptyList(), copy);
-    
-    copy = new LongArrayList(asList(1L, 2L, 3L));
-    assertEquals(asList(1L, 2L, 3L), copy);
-
-    copy = new LongArrayList(Collections.<Long>emptyList());
-    assertEquals(LongArrayList.emptyList(), copy);
-  }
-  
   public void testModificationWithIteration() {
     list.addAll(asList(1L, 2L, 3L, 4L));
     Iterator<Long> iterator = list.iterator();
diff --git a/java/core/src/test/java/com/google/protobuf/ParserTest.java b/java/core/src/test/java/com/google/protobuf/ParserTest.java
index 9d4b6b94..30842d2c 100644
--- a/java/core/src/test/java/com/google/protobuf/ParserTest.java
+++ b/java/core/src/test/java/com/google/protobuf/ParserTest.java
@@ -179,16 +179,16 @@ public class ParserTest extends TestCase {
   public void testParseExtensions() throws Exception {
     assertRoundTripEquals(TestUtil.getAllExtensionsSet(),
                           TestUtil.getExtensionRegistry());
-    assertRoundTripEquals(TestUtil.getAllLiteExtensionsSet(),
-                          TestUtil.getExtensionRegistryLite());
+    assertRoundTripEquals(
+        TestUtilLite.getAllLiteExtensionsSet(), TestUtilLite.getExtensionRegistryLite());
   }
 
   public void testParsePacked() throws Exception {
     assertRoundTripEquals(TestUtil.getPackedSet());
     assertRoundTripEquals(TestUtil.getPackedExtensionsSet(),
                           TestUtil.getExtensionRegistry());
-    assertRoundTripEquals(TestUtil.getLitePackedExtensionsSet(),
-                          TestUtil.getExtensionRegistryLite());
+    assertRoundTripEquals(
+        TestUtilLite.getLitePackedExtensionsSet(), TestUtilLite.getExtensionRegistryLite());
   }
 
   public void testParseDelimitedTo() throws Exception {
@@ -198,8 +198,7 @@ public class ParserTest extends TestCase {
     normalMessage.writeDelimitedTo(output);
 
     // Write MessageLite with packed extension fields.
-    TestPackedExtensionsLite packedMessage =
-        TestUtil.getLitePackedExtensionsSet();
+    TestPackedExtensionsLite packedMessage = TestUtilLite.getLitePackedExtensionsSet();
     packedMessage.writeDelimitedTo(output);
 
     InputStream input = new ByteArrayInputStream(output.toByteArray());
@@ -208,8 +207,9 @@ public class ParserTest extends TestCase {
         normalMessage.getParserForType().parseDelimitedFrom(input));
     assertMessageEquals(
         packedMessage,
-        packedMessage.getParserForType().parseDelimitedFrom(
-            input, TestUtil.getExtensionRegistryLite()));
+        packedMessage
+            .getParserForType()
+            .parseDelimitedFrom(input, TestUtilLite.getExtensionRegistryLite()));
   }
 
   public void testParseUnknownFields() throws Exception {
diff --git a/java/core/src/test/java/com/google/protobuf/ProtobufArrayListTest.java b/java/core/src/test/java/com/google/protobuf/ProtobufArrayListTest.java
index 245c3dee..3f45e226 100644
--- a/java/core/src/test/java/com/google/protobuf/ProtobufArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/ProtobufArrayListTest.java
@@ -63,20 +63,6 @@ public class ProtobufArrayListTest extends TestCase {
     assertImmutable(ProtobufArrayList.<Integer>emptyList());
   }
   
-  public void testCopyConstructor() {
-    ProtobufArrayList<Integer> copy = new ProtobufArrayList<Integer>(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new ProtobufArrayList<Integer>(IntArrayList.emptyList());
-    assertEquals(ProtobufArrayList.emptyList(), copy);
-    
-    copy = new ProtobufArrayList<Integer>(asList(1, 2, 3));
-    assertEquals(asList(1, 2, 3), copy);
-
-    copy = new ProtobufArrayList<Integer>(Collections.<Integer>emptyList());
-    assertEquals(ProtobufArrayList.emptyList(), copy);
-  }
-  
   public void testModificationWithIteration() {
     list.addAll(asList(1, 2, 3, 4));
     Iterator<Integer> iterator = list.iterator();
diff --git a/java/core/src/test/java/com/google/protobuf/ServiceTest.java b/java/core/src/test/java/com/google/protobuf/ServiceTest.java
index 7f3439d0..b902737d 100644
--- a/java/core/src/test/java/com/google/protobuf/ServiceTest.java
+++ b/java/core/src/test/java/com/google/protobuf/ServiceTest.java
@@ -175,12 +175,14 @@ public class ServiceTest extends TestCase {
     MethodDescriptor fooMethod =
         ServiceWithNoOuter.getDescriptor().findMethodByName("Foo");
     MessageWithNoOuter request = MessageWithNoOuter.getDefaultInstance();
-    RpcCallback<Message> callback = new RpcCallback<Message>() {
-      public void run(Message parameter) {
-        // No reason this should be run.
-        fail();
-      }
-    };
+    RpcCallback<Message> callback =
+        new RpcCallback<Message>() {
+          @Override
+          public void run(Message parameter) {
+            // No reason this should be run.
+            fail();
+          }
+        };
     RpcCallback<TestAllTypes> specializedCallback =
         RpcUtil.specializeCallback(callback);
 
@@ -290,7 +292,9 @@ public class ServiceTest extends TestCase {
     public boolean isCalled() { return called; }
 
     public void reset() { called = false; }
-    public void run(Type message) { called = true; }
+    @Override
+    public void run(Type message) {
+      called = true; }
   }
 
   /** Implementation of the wrapsCallback() argument matcher. */
@@ -301,6 +305,7 @@ public class ServiceTest extends TestCase {
       this.callback = callback;
     }
 
+    @Override
     @SuppressWarnings("unchecked")
     public boolean matches(Object actual) {
       if (!(actual instanceof RpcCallback)) {
@@ -313,6 +318,7 @@ public class ServiceTest extends TestCase {
       return callback.isCalled();
     }
 
+    @Override
     public void appendTo(StringBuffer buffer) {
       buffer.append("wrapsCallback(mockCallback)");
     }
diff --git a/java/core/src/test/java/com/google/protobuf/SmallSortedMapTest.java b/java/core/src/test/java/com/google/protobuf/SmallSortedMapTest.java
index 366086d3..e96ecd65 100644
--- a/java/core/src/test/java/com/google/protobuf/SmallSortedMapTest.java
+++ b/java/core/src/test/java/com/google/protobuf/SmallSortedMapTest.java
@@ -56,14 +56,17 @@ public class SmallSortedMapTest extends TestCase {
       this.value = value;
     }
 
+    @Override
     public K getKey() {
       return key;
     }
 
+    @Override
     public V getValue() {
       return value;
     }
 
+    @Override
     public V setValue(V value) {
       V oldValue = this.value;
       this.value = value;
diff --git a/java/core/src/test/java/com/google/protobuf/TestUtil.java b/java/core/src/test/java/com/google/protobuf/TestUtil.java
index 53d65428..08b2a76d 100644
--- a/java/core/src/test/java/com/google/protobuf/TestUtil.java
+++ b/java/core/src/test/java/com/google/protobuf/TestUtil.java
@@ -30,8 +30,6 @@
 
 package com.google.protobuf;
 
-import static com.google.protobuf.UnittestLite.OptionalGroup_extension_lite;
-import static com.google.protobuf.UnittestLite.RepeatedGroup_extension_lite;
 import static com.google.protobuf.UnittestLite.defaultBoolExtensionLite;
 import static com.google.protobuf.UnittestLite.defaultBytesExtensionLite;
 import static com.google.protobuf.UnittestLite.defaultCordExtensionLite;
@@ -216,12 +214,7 @@ import static protobuf_unittest.UnittestProto.repeatedUint32Extension;
 import static protobuf_unittest.UnittestProto.repeatedUint64Extension;
 
 import com.google.protobuf.UnittestImportLite.ImportEnumLite;
-import com.google.protobuf.UnittestImportLite.ImportMessageLite;
-import com.google.protobuf.UnittestImportPublicLite.PublicImportMessageLite;
-import com.google.protobuf.UnittestLite;
 import com.google.protobuf.UnittestLite.ForeignEnumLite;
-import com.google.protobuf.UnittestLite.ForeignMessageLite;
-import com.google.protobuf.UnittestLite.TestAllExtensionsLite;
 import com.google.protobuf.UnittestLite.TestAllExtensionsLiteOrBuilder;
 import com.google.protobuf.UnittestLite.TestAllTypesLite;
 import com.google.protobuf.UnittestLite.TestPackedExtensionsLite;
@@ -287,16 +280,6 @@ public final class TestUtil {
   }
 
   /**
-   * Get a {@code TestAllTypesLite.Builder} with all fields set as they would be by
-   * {@link #setAllFields(TestAllTypesLite.Builder)}.
-   */
-  public static TestAllTypesLite.Builder getAllLiteSetBuilder() {
-    TestAllTypesLite.Builder builder = TestAllTypesLite.newBuilder();
-    setAllFields(builder);
-    return builder;
-  }
-
-  /**
    * Get a {@code TestAllExtensions} with all fields set as they would be by
    * {@link #setAllExtensions(TestAllExtensions.Builder)}.
    */
@@ -306,12 +289,6 @@ public final class TestUtil {
     return builder.build();
   }
 
-  public static TestAllExtensionsLite getAllLiteExtensionsSet() {
-    TestAllExtensionsLite.Builder builder = TestAllExtensionsLite.newBuilder();
-    setAllExtensions(builder);
-    return builder.build();
-  }
-
   public static TestPackedTypes getPackedSet() {
     TestPackedTypes.Builder builder = TestPackedTypes.newBuilder();
     setPackedFields(builder);
@@ -330,157 +307,6 @@ public final class TestUtil {
     return builder.build();
   }
 
-  public static TestPackedExtensionsLite getLitePackedExtensionsSet() {
-    TestPackedExtensionsLite.Builder builder =
-        TestPackedExtensionsLite.newBuilder();
-    setPackedExtensions(builder);
-    return builder.build();
-  }
-  
-  /**
-   * Set every field of {@code builder} to the values expected by
-   * {@code assertAllFieldsSet()}.
-   */
-  public static void setAllFields(TestAllTypesLite.Builder builder) {
-    builder.setOptionalInt32   (101);
-    builder.setOptionalInt64   (102);
-    builder.setOptionalUint32  (103);
-    builder.setOptionalUint64  (104);
-    builder.setOptionalSint32  (105);
-    builder.setOptionalSint64  (106);
-    builder.setOptionalFixed32 (107);
-    builder.setOptionalFixed64 (108);
-    builder.setOptionalSfixed32(109);
-    builder.setOptionalSfixed64(110);
-    builder.setOptionalFloat   (111);
-    builder.setOptionalDouble  (112);
-    builder.setOptionalBool    (true);
-    builder.setOptionalString  ("115");
-    builder.setOptionalBytes   (toBytes("116"));
-
-    builder.setOptionalGroup(
-        TestAllTypesLite.OptionalGroup.newBuilder().setA(117).build());
-    builder.setOptionalNestedMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(118).build());
-    builder.setOptionalForeignMessage(
-        ForeignMessageLite.newBuilder().setC(119).build());
-    builder.setOptionalImportMessage(
-        ImportMessageLite.newBuilder().setD(120).build());
-    builder.setOptionalPublicImportMessage(
-        PublicImportMessageLite.newBuilder().setE(126).build());
-    builder.setOptionalLazyMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(127).build());
-
-    builder.setOptionalNestedEnum (TestAllTypesLite.NestedEnum.BAZ);
-    builder.setOptionalForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAZ);
-    builder.setOptionalImportEnum (ImportEnumLite.IMPORT_LITE_BAZ);
-
-    builder.setOptionalStringPiece("124");
-    builder.setOptionalCord("125");
-
-    // -----------------------------------------------------------------
-
-    builder.addRepeatedInt32   (201);
-    builder.addRepeatedInt64   (202);
-    builder.addRepeatedUint32  (203);
-    builder.addRepeatedUint64  (204);
-    builder.addRepeatedSint32  (205);
-    builder.addRepeatedSint64  (206);
-    builder.addRepeatedFixed32 (207);
-    builder.addRepeatedFixed64 (208);
-    builder.addRepeatedSfixed32(209);
-    builder.addRepeatedSfixed64(210);
-    builder.addRepeatedFloat   (211);
-    builder.addRepeatedDouble  (212);
-    builder.addRepeatedBool    (true);
-    builder.addRepeatedString  ("215");
-    builder.addRepeatedBytes   (toBytes("216"));
-
-    builder.addRepeatedGroup(
-        TestAllTypesLite.RepeatedGroup.newBuilder().setA(217).build());
-    builder.addRepeatedNestedMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(218).build());
-    builder.addRepeatedForeignMessage(
-        ForeignMessageLite.newBuilder().setC(219).build());
-    builder.addRepeatedImportMessage(
-        ImportMessageLite.newBuilder().setD(220).build());
-    builder.addRepeatedLazyMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(227).build());
-
-    builder.addRepeatedNestedEnum (TestAllTypesLite.NestedEnum.BAR);
-    builder.addRepeatedForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR);
-    builder.addRepeatedImportEnum (ImportEnumLite.IMPORT_LITE_BAR);
-
-    builder.addRepeatedStringPiece("224");
-    builder.addRepeatedCord("225");
-
-    // Add a second one of each field.
-    builder.addRepeatedInt32   (301);
-    builder.addRepeatedInt64   (302);
-    builder.addRepeatedUint32  (303);
-    builder.addRepeatedUint64  (304);
-    builder.addRepeatedSint32  (305);
-    builder.addRepeatedSint64  (306);
-    builder.addRepeatedFixed32 (307);
-    builder.addRepeatedFixed64 (308);
-    builder.addRepeatedSfixed32(309);
-    builder.addRepeatedSfixed64(310);
-    builder.addRepeatedFloat   (311);
-    builder.addRepeatedDouble  (312);
-    builder.addRepeatedBool    (false);
-    builder.addRepeatedString  ("315");
-    builder.addRepeatedBytes   (toBytes("316"));
-
-    builder.addRepeatedGroup(
-        TestAllTypesLite.RepeatedGroup.newBuilder().setA(317).build());
-    builder.addRepeatedNestedMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(318).build());
-    builder.addRepeatedForeignMessage(
-        ForeignMessageLite.newBuilder().setC(319).build());
-    builder.addRepeatedImportMessage(
-        ImportMessageLite.newBuilder().setD(320).build());
-    builder.addRepeatedLazyMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(327).build());
-
-    builder.addRepeatedNestedEnum (TestAllTypesLite.NestedEnum.BAZ);
-    builder.addRepeatedForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAZ);
-    builder.addRepeatedImportEnum (ImportEnumLite.IMPORT_LITE_BAZ);
-
-    builder.addRepeatedStringPiece("324");
-    builder.addRepeatedCord("325");
-
-    // -----------------------------------------------------------------
-
-    builder.setDefaultInt32   (401);
-    builder.setDefaultInt64   (402);
-    builder.setDefaultUint32  (403);
-    builder.setDefaultUint64  (404);
-    builder.setDefaultSint32  (405);
-    builder.setDefaultSint64  (406);
-    builder.setDefaultFixed32 (407);
-    builder.setDefaultFixed64 (408);
-    builder.setDefaultSfixed32(409);
-    builder.setDefaultSfixed64(410);
-    builder.setDefaultFloat   (411);
-    builder.setDefaultDouble  (412);
-    builder.setDefaultBool    (false);
-    builder.setDefaultString  ("415");
-    builder.setDefaultBytes   (toBytes("416"));
-
-    builder.setDefaultNestedEnum (TestAllTypesLite.NestedEnum.FOO);
-    builder.setDefaultForeignEnum(ForeignEnumLite.FOREIGN_LITE_FOO);
-    builder.setDefaultImportEnum (ImportEnumLite.IMPORT_LITE_FOO);
-
-    builder.setDefaultStringPiece("424");
-    builder.setDefaultCord("425");
-
-    builder.setOneofUint32(601);
-    builder.setOneofNestedMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(602).build());
-    builder.setOneofString("603");
-    builder.setOneofBytes(toBytes("604"));
-  }
-
   /**
    * Set every field of {@code message} to the values expected by
    * {@code assertAllFieldsSet()}.
@@ -1370,23 +1196,13 @@ public final class TestUtil {
     return registry.getUnmodifiable();
   }
 
-  public static ExtensionRegistryLite getExtensionRegistryLite() {
-    ExtensionRegistryLite registry = ExtensionRegistryLite.newInstance();
-    registerAllExtensionsLite(registry);
-    return registry.getUnmodifiable();
-  }
-
   /**
    * Register all of {@code TestAllExtensions}'s extensions with the
    * given {@link ExtensionRegistry}.
    */
   public static void registerAllExtensions(ExtensionRegistry registry) {
     UnittestProto.registerAllExtensions(registry);
-    registerAllExtensionsLite(registry);
-  }
-
-  public static void registerAllExtensionsLite(ExtensionRegistryLite registry) {
-    UnittestLite.registerAllExtensions(registry);
+    TestUtilLite.registerAllExtensionsLite(registry);
   }
 
   /**
@@ -2180,195 +1996,6 @@ public final class TestUtil {
   // Lite extensions
 
   /**
-   * Set every field of {@code message} to the values expected by
-   * {@code assertAllExtensionsSet()}.
-   */
-  public static void setAllExtensions(TestAllExtensionsLite.Builder message) {
-    message.setExtension(optionalInt32ExtensionLite   , 101);
-    message.setExtension(optionalInt64ExtensionLite   , 102L);
-    message.setExtension(optionalUint32ExtensionLite  , 103);
-    message.setExtension(optionalUint64ExtensionLite  , 104L);
-    message.setExtension(optionalSint32ExtensionLite  , 105);
-    message.setExtension(optionalSint64ExtensionLite  , 106L);
-    message.setExtension(optionalFixed32ExtensionLite , 107);
-    message.setExtension(optionalFixed64ExtensionLite , 108L);
-    message.setExtension(optionalSfixed32ExtensionLite, 109);
-    message.setExtension(optionalSfixed64ExtensionLite, 110L);
-    message.setExtension(optionalFloatExtensionLite   , 111F);
-    message.setExtension(optionalDoubleExtensionLite  , 112D);
-    message.setExtension(optionalBoolExtensionLite    , true);
-    message.setExtension(optionalStringExtensionLite  , "115");
-    message.setExtension(optionalBytesExtensionLite   , toBytes("116"));
-
-    message.setExtension(optionalGroupExtensionLite,
-      OptionalGroup_extension_lite.newBuilder().setA(117).build());
-    message.setExtension(optionalNestedMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(118).build());
-    message.setExtension(optionalForeignMessageExtensionLite,
-      ForeignMessageLite.newBuilder().setC(119).build());
-    message.setExtension(optionalImportMessageExtensionLite,
-      ImportMessageLite.newBuilder().setD(120).build());
-    message.setExtension(optionalPublicImportMessageExtensionLite,
-      PublicImportMessageLite.newBuilder().setE(126).build());
-    message.setExtension(optionalLazyMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(127).build());
-
-    message.setExtension(optionalNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAZ);
-    message.setExtension(optionalForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
-    message.setExtension(optionalImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAZ);
-
-    message.setExtension(optionalStringPieceExtensionLite, "124");
-    message.setExtension(optionalCordExtensionLite, "125");
-
-    // -----------------------------------------------------------------
-
-    message.addExtension(repeatedInt32ExtensionLite   , 201);
-    message.addExtension(repeatedInt64ExtensionLite   , 202L);
-    message.addExtension(repeatedUint32ExtensionLite  , 203);
-    message.addExtension(repeatedUint64ExtensionLite  , 204L);
-    message.addExtension(repeatedSint32ExtensionLite  , 205);
-    message.addExtension(repeatedSint64ExtensionLite  , 206L);
-    message.addExtension(repeatedFixed32ExtensionLite , 207);
-    message.addExtension(repeatedFixed64ExtensionLite , 208L);
-    message.addExtension(repeatedSfixed32ExtensionLite, 209);
-    message.addExtension(repeatedSfixed64ExtensionLite, 210L);
-    message.addExtension(repeatedFloatExtensionLite   , 211F);
-    message.addExtension(repeatedDoubleExtensionLite  , 212D);
-    message.addExtension(repeatedBoolExtensionLite    , true);
-    message.addExtension(repeatedStringExtensionLite  , "215");
-    message.addExtension(repeatedBytesExtensionLite   , toBytes("216"));
-
-    message.addExtension(repeatedGroupExtensionLite,
-      RepeatedGroup_extension_lite.newBuilder().setA(217).build());
-    message.addExtension(repeatedNestedMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(218).build());
-    message.addExtension(repeatedForeignMessageExtensionLite,
-      ForeignMessageLite.newBuilder().setC(219).build());
-    message.addExtension(repeatedImportMessageExtensionLite,
-      ImportMessageLite.newBuilder().setD(220).build());
-    message.addExtension(repeatedLazyMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(227).build());
-
-    message.addExtension(repeatedNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAR);
-    message.addExtension(repeatedForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAR);
-    message.addExtension(repeatedImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAR);
-
-    message.addExtension(repeatedStringPieceExtensionLite, "224");
-    message.addExtension(repeatedCordExtensionLite, "225");
-
-    // Add a second one of each field.
-    message.addExtension(repeatedInt32ExtensionLite   , 301);
-    message.addExtension(repeatedInt64ExtensionLite   , 302L);
-    message.addExtension(repeatedUint32ExtensionLite  , 303);
-    message.addExtension(repeatedUint64ExtensionLite  , 304L);
-    message.addExtension(repeatedSint32ExtensionLite  , 305);
-    message.addExtension(repeatedSint64ExtensionLite  , 306L);
-    message.addExtension(repeatedFixed32ExtensionLite , 307);
-    message.addExtension(repeatedFixed64ExtensionLite , 308L);
-    message.addExtension(repeatedSfixed32ExtensionLite, 309);
-    message.addExtension(repeatedSfixed64ExtensionLite, 310L);
-    message.addExtension(repeatedFloatExtensionLite   , 311F);
-    message.addExtension(repeatedDoubleExtensionLite  , 312D);
-    message.addExtension(repeatedBoolExtensionLite    , false);
-    message.addExtension(repeatedStringExtensionLite  , "315");
-    message.addExtension(repeatedBytesExtensionLite   , toBytes("316"));
-
-    message.addExtension(repeatedGroupExtensionLite,
-      RepeatedGroup_extension_lite.newBuilder().setA(317).build());
-    message.addExtension(repeatedNestedMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(318).build());
-    message.addExtension(repeatedForeignMessageExtensionLite,
-      ForeignMessageLite.newBuilder().setC(319).build());
-    message.addExtension(repeatedImportMessageExtensionLite,
-      ImportMessageLite.newBuilder().setD(320).build());
-    message.addExtension(repeatedLazyMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(327).build());
-
-    message.addExtension(repeatedNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAZ);
-    message.addExtension(repeatedForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
-    message.addExtension(repeatedImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAZ);
-
-    message.addExtension(repeatedStringPieceExtensionLite, "324");
-    message.addExtension(repeatedCordExtensionLite, "325");
-
-    // -----------------------------------------------------------------
-
-    message.setExtension(defaultInt32ExtensionLite   , 401);
-    message.setExtension(defaultInt64ExtensionLite   , 402L);
-    message.setExtension(defaultUint32ExtensionLite  , 403);
-    message.setExtension(defaultUint64ExtensionLite  , 404L);
-    message.setExtension(defaultSint32ExtensionLite  , 405);
-    message.setExtension(defaultSint64ExtensionLite  , 406L);
-    message.setExtension(defaultFixed32ExtensionLite , 407);
-    message.setExtension(defaultFixed64ExtensionLite , 408L);
-    message.setExtension(defaultSfixed32ExtensionLite, 409);
-    message.setExtension(defaultSfixed64ExtensionLite, 410L);
-    message.setExtension(defaultFloatExtensionLite   , 411F);
-    message.setExtension(defaultDoubleExtensionLite  , 412D);
-    message.setExtension(defaultBoolExtensionLite    , false);
-    message.setExtension(defaultStringExtensionLite  , "415");
-    message.setExtension(defaultBytesExtensionLite   , toBytes("416"));
-
-    message.setExtension(defaultNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.FOO);
-    message.setExtension(defaultForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_FOO);
-    message.setExtension(defaultImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_FOO);
-
-    message.setExtension(defaultStringPieceExtensionLite, "424");
-    message.setExtension(defaultCordExtensionLite, "425");
-
-    message.setExtension(oneofUint32ExtensionLite, 601);
-    message.setExtension(oneofNestedMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(602).build());
-    message.setExtension(oneofStringExtensionLite, "603");
-    message.setExtension(oneofBytesExtensionLite, toBytes("604"));
-  }
-
-  // -------------------------------------------------------------------
-
-  /**
-   * Modify the repeated extensions of {@code message} to contain the values
-   * expected by {@code assertRepeatedExtensionsModified()}.
-   */
-  public static void modifyRepeatedExtensions(
-      TestAllExtensionsLite.Builder message) {
-    message.setExtension(repeatedInt32ExtensionLite   , 1, 501);
-    message.setExtension(repeatedInt64ExtensionLite   , 1, 502L);
-    message.setExtension(repeatedUint32ExtensionLite  , 1, 503);
-    message.setExtension(repeatedUint64ExtensionLite  , 1, 504L);
-    message.setExtension(repeatedSint32ExtensionLite  , 1, 505);
-    message.setExtension(repeatedSint64ExtensionLite  , 1, 506L);
-    message.setExtension(repeatedFixed32ExtensionLite , 1, 507);
-    message.setExtension(repeatedFixed64ExtensionLite , 1, 508L);
-    message.setExtension(repeatedSfixed32ExtensionLite, 1, 509);
-    message.setExtension(repeatedSfixed64ExtensionLite, 1, 510L);
-    message.setExtension(repeatedFloatExtensionLite   , 1, 511F);
-    message.setExtension(repeatedDoubleExtensionLite  , 1, 512D);
-    message.setExtension(repeatedBoolExtensionLite    , 1, true);
-    message.setExtension(repeatedStringExtensionLite  , 1, "515");
-    message.setExtension(repeatedBytesExtensionLite   , 1, toBytes("516"));
-
-    message.setExtension(repeatedGroupExtensionLite, 1,
-      RepeatedGroup_extension_lite.newBuilder().setA(517).build());
-    message.setExtension(repeatedNestedMessageExtensionLite, 1,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(518).build());
-    message.setExtension(repeatedForeignMessageExtensionLite, 1,
-      ForeignMessageLite.newBuilder().setC(519).build());
-    message.setExtension(repeatedImportMessageExtensionLite, 1,
-      ImportMessageLite.newBuilder().setD(520).build());
-    message.setExtension(repeatedLazyMessageExtensionLite, 1,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(527).build());
-
-    message.setExtension(repeatedNestedEnumExtensionLite , 1, TestAllTypesLite.NestedEnum.FOO);
-    message.setExtension(repeatedForeignEnumExtensionLite, 1, ForeignEnumLite.FOREIGN_LITE_FOO);
-    message.setExtension(repeatedImportEnumExtensionLite , 1, ImportEnumLite.IMPORT_LITE_FOO);
-
-    message.setExtension(repeatedStringPieceExtensionLite, 1, "524");
-    message.setExtension(repeatedCordExtensionLite, 1, "525");
-  }
-
-  // -------------------------------------------------------------------
-
-  /**
    * Assert (using {@code junit.framework.Assert}} that all extensions of
    * {@code message} are set to the values assigned by {@code setAllExtensions}.
    */
@@ -2867,38 +2494,6 @@ public final class TestUtil {
     assertEqualsExactType("525", message.getExtension(repeatedCordExtensionLite, 1));
   }
 
-  public static void setPackedExtensions(TestPackedExtensionsLite.Builder message) {
-    message.addExtension(packedInt32ExtensionLite   , 601);
-    message.addExtension(packedInt64ExtensionLite   , 602L);
-    message.addExtension(packedUint32ExtensionLite  , 603);
-    message.addExtension(packedUint64ExtensionLite  , 604L);
-    message.addExtension(packedSint32ExtensionLite  , 605);
-    message.addExtension(packedSint64ExtensionLite  , 606L);
-    message.addExtension(packedFixed32ExtensionLite , 607);
-    message.addExtension(packedFixed64ExtensionLite , 608L);
-    message.addExtension(packedSfixed32ExtensionLite, 609);
-    message.addExtension(packedSfixed64ExtensionLite, 610L);
-    message.addExtension(packedFloatExtensionLite   , 611F);
-    message.addExtension(packedDoubleExtensionLite  , 612D);
-    message.addExtension(packedBoolExtensionLite    , true);
-    message.addExtension(packedEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAR);
-    // Add a second one of each field.
-    message.addExtension(packedInt32ExtensionLite   , 701);
-    message.addExtension(packedInt64ExtensionLite   , 702L);
-    message.addExtension(packedUint32ExtensionLite  , 703);
-    message.addExtension(packedUint64ExtensionLite  , 704L);
-    message.addExtension(packedSint32ExtensionLite  , 705);
-    message.addExtension(packedSint64ExtensionLite  , 706L);
-    message.addExtension(packedFixed32ExtensionLite , 707);
-    message.addExtension(packedFixed64ExtensionLite , 708L);
-    message.addExtension(packedSfixed32ExtensionLite, 709);
-    message.addExtension(packedSfixed64ExtensionLite, 710L);
-    message.addExtension(packedFloatExtensionLite   , 711F);
-    message.addExtension(packedDoubleExtensionLite  , 712D);
-    message.addExtension(packedBoolExtensionLite    , false);
-    message.addExtension(packedEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
-  }
-
   public static void assertPackedExtensionsSet(TestPackedExtensionsLite message) {
     Assert.assertEquals(2, message.getExtensionCount(packedInt32ExtensionLite   ));
     Assert.assertEquals(2, message.getExtensionCount(packedInt64ExtensionLite   ));
@@ -4250,7 +3845,7 @@ public final class TestUtil {
 
     private int invalidations;
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public void markDirty() {
       invalidations++;
     }
diff --git a/java/core/src/test/java/com/google/protobuf/TestUtilLite.java b/java/core/src/test/java/com/google/protobuf/TestUtilLite.java
new file mode 100644
index 00000000..8f33fa14
--- /dev/null
+++ b/java/core/src/test/java/com/google/protobuf/TestUtilLite.java
@@ -0,0 +1,559 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+import static com.google.protobuf.UnittestLite.OptionalGroup_extension_lite;
+import static com.google.protobuf.UnittestLite.RepeatedGroup_extension_lite;
+import static com.google.protobuf.UnittestLite.defaultBoolExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultBytesExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultCordExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultDoubleExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultFixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultFixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultFloatExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultForeignEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultImportEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultInt32ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultInt64ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultNestedEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultSfixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultSfixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultSint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultSint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultStringExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultStringPieceExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultUint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultUint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.oneofBytesExtensionLite;
+import static com.google.protobuf.UnittestLite.oneofNestedMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.oneofStringExtensionLite;
+import static com.google.protobuf.UnittestLite.oneofUint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalBoolExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalBytesExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalCordExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalDoubleExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalFixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalFixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalFloatExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalForeignEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalForeignMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalGroupExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalImportEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalImportMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalInt32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalInt64ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalLazyMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalNestedEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalNestedMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalPublicImportMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalSfixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalSfixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalSint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalSint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalStringExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalStringPieceExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalUint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalUint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedBoolExtensionLite;
+import static com.google.protobuf.UnittestLite.packedDoubleExtensionLite;
+import static com.google.protobuf.UnittestLite.packedEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.packedFixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedFixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedFloatExtensionLite;
+import static com.google.protobuf.UnittestLite.packedInt32ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedInt64ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedSfixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedSfixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedSint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedSint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedUint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedUint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedBoolExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedBytesExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedCordExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedDoubleExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedFixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedFixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedFloatExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedForeignEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedForeignMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedGroupExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedImportEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedImportMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedInt32ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedInt64ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedLazyMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedNestedEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedNestedMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedSfixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedSfixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedSint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedSint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedStringExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedStringPieceExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedUint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedUint64ExtensionLite;
+
+import com.google.protobuf.UnittestImportLite.ImportEnumLite;
+import com.google.protobuf.UnittestImportLite.ImportMessageLite;
+import com.google.protobuf.UnittestImportPublicLite.PublicImportMessageLite;
+import com.google.protobuf.UnittestLite.ForeignEnumLite;
+import com.google.protobuf.UnittestLite.ForeignMessageLite;
+import com.google.protobuf.UnittestLite.TestAllExtensionsLite;
+import com.google.protobuf.UnittestLite.TestAllTypesLite;
+import com.google.protobuf.UnittestLite.TestPackedExtensionsLite;
+
+/**
+ * Contains methods for setting fields of {@code TestAllTypesLite}, {@code TestAllExtensionsLite},
+ * and {@code TestPackedExtensionsLite}. This is analogous to the functionality in TestUtil.java but
+ * does not depend on the presence of any non-lite protos.
+ *
+ * <p>This code is not to be used outside of {@code com.google.protobuf} and
+ * subpackages.
+ */
+public final class TestUtilLite {
+  private TestUtilLite() {}
+
+  /** Helper to convert a String to ByteString. */
+  static ByteString toBytes(String str) {
+    return ByteString.copyFrom(str.getBytes(Internal.UTF_8));
+  }
+
+  /**
+   * Get a {@code TestAllTypesLite.Builder} with all fields set as they would be by
+   * {@link #setAllFields(TestAllTypesLite.Builder)}.
+   */
+  public static TestAllTypesLite.Builder getAllLiteSetBuilder() {
+    TestAllTypesLite.Builder builder = TestAllTypesLite.newBuilder();
+    setAllFields(builder);
+    return builder;
+  }
+
+  /**
+   * Get a {@code TestAllExtensionsLite} with all fields set as they would be by
+   * {@link #setAllExtensions(TestAllExtensionsLite.Builder)}.
+   */
+  public static TestAllExtensionsLite getAllLiteExtensionsSet() {
+    TestAllExtensionsLite.Builder builder = TestAllExtensionsLite.newBuilder();
+    setAllExtensions(builder);
+    return builder.build();
+  }
+
+  public static TestPackedExtensionsLite getLitePackedExtensionsSet() {
+    TestPackedExtensionsLite.Builder builder = TestPackedExtensionsLite.newBuilder();
+    setPackedExtensions(builder);
+    return builder.build();
+  }
+  
+  /**
+   * Set every field of {@code builder} to the values expected by
+   * {@code assertAllFieldsSet()}.
+   */
+  public static void setAllFields(TestAllTypesLite.Builder builder) {
+    builder.setOptionalInt32   (101);
+    builder.setOptionalInt64   (102);
+    builder.setOptionalUint32  (103);
+    builder.setOptionalUint64  (104);
+    builder.setOptionalSint32  (105);
+    builder.setOptionalSint64  (106);
+    builder.setOptionalFixed32 (107);
+    builder.setOptionalFixed64 (108);
+    builder.setOptionalSfixed32(109);
+    builder.setOptionalSfixed64(110);
+    builder.setOptionalFloat   (111);
+    builder.setOptionalDouble  (112);
+    builder.setOptionalBool    (true);
+    builder.setOptionalString  ("115");
+    builder.setOptionalBytes   (toBytes("116"));
+
+    builder.setOptionalGroup(
+        TestAllTypesLite.OptionalGroup.newBuilder().setA(117).build());
+    builder.setOptionalNestedMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(118).build());
+    builder.setOptionalForeignMessage(
+        ForeignMessageLite.newBuilder().setC(119).build());
+    builder.setOptionalImportMessage(
+        ImportMessageLite.newBuilder().setD(120).build());
+    builder.setOptionalPublicImportMessage(
+        PublicImportMessageLite.newBuilder().setE(126).build());
+    builder.setOptionalLazyMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(127).build());
+
+    builder.setOptionalNestedEnum (TestAllTypesLite.NestedEnum.BAZ);
+    builder.setOptionalForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAZ);
+    builder.setOptionalImportEnum (ImportEnumLite.IMPORT_LITE_BAZ);
+
+    builder.setOptionalStringPiece("124");
+    builder.setOptionalCord("125");
+
+    // -----------------------------------------------------------------
+
+    builder.addRepeatedInt32   (201);
+    builder.addRepeatedInt64   (202);
+    builder.addRepeatedUint32  (203);
+    builder.addRepeatedUint64  (204);
+    builder.addRepeatedSint32  (205);
+    builder.addRepeatedSint64  (206);
+    builder.addRepeatedFixed32 (207);
+    builder.addRepeatedFixed64 (208);
+    builder.addRepeatedSfixed32(209);
+    builder.addRepeatedSfixed64(210);
+    builder.addRepeatedFloat   (211);
+    builder.addRepeatedDouble  (212);
+    builder.addRepeatedBool    (true);
+    builder.addRepeatedString  ("215");
+    builder.addRepeatedBytes   (toBytes("216"));
+
+    builder.addRepeatedGroup(
+        TestAllTypesLite.RepeatedGroup.newBuilder().setA(217).build());
+    builder.addRepeatedNestedMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(218).build());
+    builder.addRepeatedForeignMessage(
+        ForeignMessageLite.newBuilder().setC(219).build());
+    builder.addRepeatedImportMessage(
+        ImportMessageLite.newBuilder().setD(220).build());
+    builder.addRepeatedLazyMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(227).build());
+
+    builder.addRepeatedNestedEnum (TestAllTypesLite.NestedEnum.BAR);
+    builder.addRepeatedForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR);
+    builder.addRepeatedImportEnum (ImportEnumLite.IMPORT_LITE_BAR);
+
+    builder.addRepeatedStringPiece("224");
+    builder.addRepeatedCord("225");
+
+    // Add a second one of each field.
+    builder.addRepeatedInt32   (301);
+    builder.addRepeatedInt64   (302);
+    builder.addRepeatedUint32  (303);
+    builder.addRepeatedUint64  (304);
+    builder.addRepeatedSint32  (305);
+    builder.addRepeatedSint64  (306);
+    builder.addRepeatedFixed32 (307);
+    builder.addRepeatedFixed64 (308);
+    builder.addRepeatedSfixed32(309);
+    builder.addRepeatedSfixed64(310);
+    builder.addRepeatedFloat   (311);
+    builder.addRepeatedDouble  (312);
+    builder.addRepeatedBool    (false);
+    builder.addRepeatedString  ("315");
+    builder.addRepeatedBytes   (toBytes("316"));
+
+    builder.addRepeatedGroup(
+        TestAllTypesLite.RepeatedGroup.newBuilder().setA(317).build());
+    builder.addRepeatedNestedMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(318).build());
+    builder.addRepeatedForeignMessage(
+        ForeignMessageLite.newBuilder().setC(319).build());
+    builder.addRepeatedImportMessage(
+        ImportMessageLite.newBuilder().setD(320).build());
+    builder.addRepeatedLazyMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(327).build());
+
+    builder.addRepeatedNestedEnum (TestAllTypesLite.NestedEnum.BAZ);
+    builder.addRepeatedForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAZ);
+    builder.addRepeatedImportEnum (ImportEnumLite.IMPORT_LITE_BAZ);
+
+    builder.addRepeatedStringPiece("324");
+    builder.addRepeatedCord("325");
+
+    // -----------------------------------------------------------------
+
+    builder.setDefaultInt32   (401);
+    builder.setDefaultInt64   (402);
+    builder.setDefaultUint32  (403);
+    builder.setDefaultUint64  (404);
+    builder.setDefaultSint32  (405);
+    builder.setDefaultSint64  (406);
+    builder.setDefaultFixed32 (407);
+    builder.setDefaultFixed64 (408);
+    builder.setDefaultSfixed32(409);
+    builder.setDefaultSfixed64(410);
+    builder.setDefaultFloat   (411);
+    builder.setDefaultDouble  (412);
+    builder.setDefaultBool    (false);
+    builder.setDefaultString  ("415");
+    builder.setDefaultBytes   (toBytes("416"));
+
+    builder.setDefaultNestedEnum (TestAllTypesLite.NestedEnum.FOO);
+    builder.setDefaultForeignEnum(ForeignEnumLite.FOREIGN_LITE_FOO);
+    builder.setDefaultImportEnum (ImportEnumLite.IMPORT_LITE_FOO);
+
+    builder.setDefaultStringPiece("424");
+    builder.setDefaultCord("425");
+
+    builder.setOneofUint32(601);
+    builder.setOneofNestedMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(602).build());
+    builder.setOneofString("603");
+    builder.setOneofBytes(toBytes("604"));
+  }
+
+  /**
+   * Get an unmodifiable {@link ExtensionRegistryLite} containing all the
+   * extensions of {@code TestAllExtensionsLite}.
+   */
+  public static ExtensionRegistryLite getExtensionRegistryLite() {
+    ExtensionRegistryLite registry = ExtensionRegistryLite.newInstance();
+    registerAllExtensionsLite(registry);
+    return registry.getUnmodifiable();
+  }
+
+  /**
+   * Register all of {@code TestAllExtensionsLite}'s extensions with the
+   * given {@link ExtensionRegistryLite}.
+   */
+  public static void registerAllExtensionsLite(ExtensionRegistryLite registry) {
+    UnittestLite.registerAllExtensions(registry);
+  }
+
+  // ===================================================================
+  // Lite extensions
+
+  /**
+   * Set every field of {@code message} to the values expected by
+   * {@code assertAllExtensionsSet()}.
+   */
+  public static void setAllExtensions(TestAllExtensionsLite.Builder message) {
+    message.setExtension(optionalInt32ExtensionLite   , 101);
+    message.setExtension(optionalInt64ExtensionLite   , 102L);
+    message.setExtension(optionalUint32ExtensionLite  , 103);
+    message.setExtension(optionalUint64ExtensionLite  , 104L);
+    message.setExtension(optionalSint32ExtensionLite  , 105);
+    message.setExtension(optionalSint64ExtensionLite  , 106L);
+    message.setExtension(optionalFixed32ExtensionLite , 107);
+    message.setExtension(optionalFixed64ExtensionLite , 108L);
+    message.setExtension(optionalSfixed32ExtensionLite, 109);
+    message.setExtension(optionalSfixed64ExtensionLite, 110L);
+    message.setExtension(optionalFloatExtensionLite   , 111F);
+    message.setExtension(optionalDoubleExtensionLite  , 112D);
+    message.setExtension(optionalBoolExtensionLite    , true);
+    message.setExtension(optionalStringExtensionLite  , "115");
+    message.setExtension(optionalBytesExtensionLite   , toBytes("116"));
+
+    message.setExtension(optionalGroupExtensionLite,
+      OptionalGroup_extension_lite.newBuilder().setA(117).build());
+    message.setExtension(optionalNestedMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(118).build());
+    message.setExtension(optionalForeignMessageExtensionLite,
+      ForeignMessageLite.newBuilder().setC(119).build());
+    message.setExtension(optionalImportMessageExtensionLite,
+      ImportMessageLite.newBuilder().setD(120).build());
+    message.setExtension(optionalPublicImportMessageExtensionLite,
+      PublicImportMessageLite.newBuilder().setE(126).build());
+    message.setExtension(optionalLazyMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(127).build());
+
+    message.setExtension(optionalNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAZ);
+    message.setExtension(optionalForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
+    message.setExtension(optionalImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAZ);
+
+    message.setExtension(optionalStringPieceExtensionLite, "124");
+    message.setExtension(optionalCordExtensionLite, "125");
+
+    // -----------------------------------------------------------------
+
+    message.addExtension(repeatedInt32ExtensionLite   , 201);
+    message.addExtension(repeatedInt64ExtensionLite   , 202L);
+    message.addExtension(repeatedUint32ExtensionLite  , 203);
+    message.addExtension(repeatedUint64ExtensionLite  , 204L);
+    message.addExtension(repeatedSint32ExtensionLite  , 205);
+    message.addExtension(repeatedSint64ExtensionLite  , 206L);
+    message.addExtension(repeatedFixed32ExtensionLite , 207);
+    message.addExtension(repeatedFixed64ExtensionLite , 208L);
+    message.addExtension(repeatedSfixed32ExtensionLite, 209);
+    message.addExtension(repeatedSfixed64ExtensionLite, 210L);
+    message.addExtension(repeatedFloatExtensionLite   , 211F);
+    message.addExtension(repeatedDoubleExtensionLite  , 212D);
+    message.addExtension(repeatedBoolExtensionLite    , true);
+    message.addExtension(repeatedStringExtensionLite  , "215");
+    message.addExtension(repeatedBytesExtensionLite   , toBytes("216"));
+
+    message.addExtension(repeatedGroupExtensionLite,
+      RepeatedGroup_extension_lite.newBuilder().setA(217).build());
+    message.addExtension(repeatedNestedMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(218).build());
+    message.addExtension(repeatedForeignMessageExtensionLite,
+      ForeignMessageLite.newBuilder().setC(219).build());
+    message.addExtension(repeatedImportMessageExtensionLite,
+      ImportMessageLite.newBuilder().setD(220).build());
+    message.addExtension(repeatedLazyMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(227).build());
+
+    message.addExtension(repeatedNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAR);
+    message.addExtension(repeatedForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAR);
+    message.addExtension(repeatedImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAR);
+
+    message.addExtension(repeatedStringPieceExtensionLite, "224");
+    message.addExtension(repeatedCordExtensionLite, "225");
+
+    // Add a second one of each field.
+    message.addExtension(repeatedInt32ExtensionLite   , 301);
+    message.addExtension(repeatedInt64ExtensionLite   , 302L);
+    message.addExtension(repeatedUint32ExtensionLite  , 303);
+    message.addExtension(repeatedUint64ExtensionLite  , 304L);
+    message.addExtension(repeatedSint32ExtensionLite  , 305);
+    message.addExtension(repeatedSint64ExtensionLite  , 306L);
+    message.addExtension(repeatedFixed32ExtensionLite , 307);
+    message.addExtension(repeatedFixed64ExtensionLite , 308L);
+    message.addExtension(repeatedSfixed32ExtensionLite, 309);
+    message.addExtension(repeatedSfixed64ExtensionLite, 310L);
+    message.addExtension(repeatedFloatExtensionLite   , 311F);
+    message.addExtension(repeatedDoubleExtensionLite  , 312D);
+    message.addExtension(repeatedBoolExtensionLite    , false);
+    message.addExtension(repeatedStringExtensionLite  , "315");
+    message.addExtension(repeatedBytesExtensionLite   , toBytes("316"));
+
+    message.addExtension(repeatedGroupExtensionLite,
+      RepeatedGroup_extension_lite.newBuilder().setA(317).build());
+    message.addExtension(repeatedNestedMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(318).build());
+    message.addExtension(repeatedForeignMessageExtensionLite,
+      ForeignMessageLite.newBuilder().setC(319).build());
+    message.addExtension(repeatedImportMessageExtensionLite,
+      ImportMessageLite.newBuilder().setD(320).build());
+    message.addExtension(repeatedLazyMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(327).build());
+
+    message.addExtension(repeatedNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAZ);
+    message.addExtension(repeatedForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
+    message.addExtension(repeatedImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAZ);
+
+    message.addExtension(repeatedStringPieceExtensionLite, "324");
+    message.addExtension(repeatedCordExtensionLite, "325");
+
+    // -----------------------------------------------------------------
+
+    message.setExtension(defaultInt32ExtensionLite   , 401);
+    message.setExtension(defaultInt64ExtensionLite   , 402L);
+    message.setExtension(defaultUint32ExtensionLite  , 403);
+    message.setExtension(defaultUint64ExtensionLite  , 404L);
+    message.setExtension(defaultSint32ExtensionLite  , 405);
+    message.setExtension(defaultSint64ExtensionLite  , 406L);
+    message.setExtension(defaultFixed32ExtensionLite , 407);
+    message.setExtension(defaultFixed64ExtensionLite , 408L);
+    message.setExtension(defaultSfixed32ExtensionLite, 409);
+    message.setExtension(defaultSfixed64ExtensionLite, 410L);
+    message.setExtension(defaultFloatExtensionLite   , 411F);
+    message.setExtension(defaultDoubleExtensionLite  , 412D);
+    message.setExtension(defaultBoolExtensionLite    , false);
+    message.setExtension(defaultStringExtensionLite  , "415");
+    message.setExtension(defaultBytesExtensionLite   , toBytes("416"));
+
+    message.setExtension(defaultNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.FOO);
+    message.setExtension(defaultForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_FOO);
+    message.setExtension(defaultImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_FOO);
+
+    message.setExtension(defaultStringPieceExtensionLite, "424");
+    message.setExtension(defaultCordExtensionLite, "425");
+
+    message.setExtension(oneofUint32ExtensionLite, 601);
+    message.setExtension(oneofNestedMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(602).build());
+    message.setExtension(oneofStringExtensionLite, "603");
+    message.setExtension(oneofBytesExtensionLite, toBytes("604"));
+  }
+
+  // -------------------------------------------------------------------
+
+  /**
+   * Modify the repeated extensions of {@code message} to contain the values
+   * expected by {@code assertRepeatedExtensionsModified()}.
+   */
+  public static void modifyRepeatedExtensions(
+      TestAllExtensionsLite.Builder message) {
+    message.setExtension(repeatedInt32ExtensionLite   , 1, 501);
+    message.setExtension(repeatedInt64ExtensionLite   , 1, 502L);
+    message.setExtension(repeatedUint32ExtensionLite  , 1, 503);
+    message.setExtension(repeatedUint64ExtensionLite  , 1, 504L);
+    message.setExtension(repeatedSint32ExtensionLite  , 1, 505);
+    message.setExtension(repeatedSint64ExtensionLite  , 1, 506L);
+    message.setExtension(repeatedFixed32ExtensionLite , 1, 507);
+    message.setExtension(repeatedFixed64ExtensionLite , 1, 508L);
+    message.setExtension(repeatedSfixed32ExtensionLite, 1, 509);
+    message.setExtension(repeatedSfixed64ExtensionLite, 1, 510L);
+    message.setExtension(repeatedFloatExtensionLite   , 1, 511F);
+    message.setExtension(repeatedDoubleExtensionLite  , 1, 512D);
+    message.setExtension(repeatedBoolExtensionLite    , 1, true);
+    message.setExtension(repeatedStringExtensionLite  , 1, "515");
+    message.setExtension(repeatedBytesExtensionLite   , 1, toBytes("516"));
+
+    message.setExtension(repeatedGroupExtensionLite, 1,
+      RepeatedGroup_extension_lite.newBuilder().setA(517).build());
+    message.setExtension(repeatedNestedMessageExtensionLite, 1,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(518).build());
+    message.setExtension(repeatedForeignMessageExtensionLite, 1,
+      ForeignMessageLite.newBuilder().setC(519).build());
+    message.setExtension(repeatedImportMessageExtensionLite, 1,
+      ImportMessageLite.newBuilder().setD(520).build());
+    message.setExtension(repeatedLazyMessageExtensionLite, 1,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(527).build());
+
+    message.setExtension(repeatedNestedEnumExtensionLite , 1, TestAllTypesLite.NestedEnum.FOO);
+    message.setExtension(repeatedForeignEnumExtensionLite, 1, ForeignEnumLite.FOREIGN_LITE_FOO);
+    message.setExtension(repeatedImportEnumExtensionLite , 1, ImportEnumLite.IMPORT_LITE_FOO);
+
+    message.setExtension(repeatedStringPieceExtensionLite, 1, "524");
+    message.setExtension(repeatedCordExtensionLite, 1, "525");
+  }
+
+  public static void setPackedExtensions(TestPackedExtensionsLite.Builder message) {
+    message.addExtension(packedInt32ExtensionLite   , 601);
+    message.addExtension(packedInt64ExtensionLite   , 602L);
+    message.addExtension(packedUint32ExtensionLite  , 603);
+    message.addExtension(packedUint64ExtensionLite  , 604L);
+    message.addExtension(packedSint32ExtensionLite  , 605);
+    message.addExtension(packedSint64ExtensionLite  , 606L);
+    message.addExtension(packedFixed32ExtensionLite , 607);
+    message.addExtension(packedFixed64ExtensionLite , 608L);
+    message.addExtension(packedSfixed32ExtensionLite, 609);
+    message.addExtension(packedSfixed64ExtensionLite, 610L);
+    message.addExtension(packedFloatExtensionLite   , 611F);
+    message.addExtension(packedDoubleExtensionLite  , 612D);
+    message.addExtension(packedBoolExtensionLite    , true);
+    message.addExtension(packedEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAR);
+    // Add a second one of each field.
+    message.addExtension(packedInt32ExtensionLite   , 701);
+    message.addExtension(packedInt64ExtensionLite   , 702L);
+    message.addExtension(packedUint32ExtensionLite  , 703);
+    message.addExtension(packedUint64ExtensionLite  , 704L);
+    message.addExtension(packedSint32ExtensionLite  , 705);
+    message.addExtension(packedSint64ExtensionLite  , 706L);
+    message.addExtension(packedFixed32ExtensionLite , 707);
+    message.addExtension(packedFixed64ExtensionLite , 708L);
+    message.addExtension(packedSfixed32ExtensionLite, 709);
+    message.addExtension(packedSfixed64ExtensionLite, 710L);
+    message.addExtension(packedFloatExtensionLite   , 711F);
+    message.addExtension(packedDoubleExtensionLite  , 712D);
+    message.addExtension(packedBoolExtensionLite    , false);
+    message.addExtension(packedEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
+  }
+}
diff --git a/java/core/src/test/java/com/google/protobuf/TextFormatTest.java b/java/core/src/test/java/com/google/protobuf/TextFormatTest.java
index 3f47d924..63c17cd0 100644
--- a/java/core/src/test/java/com/google/protobuf/TextFormatTest.java
+++ b/java/core/src/test/java/com/google/protobuf/TextFormatTest.java
@@ -775,11 +775,14 @@ public class TextFormatTest extends TestCase {
   public void testParseBoolean() throws Exception {
     String goodText =
         "repeated_bool: t  repeated_bool : 0\n" +
-        "repeated_bool :f repeated_bool:1";
+        "repeated_bool :f repeated_bool:1\n" +
+        "repeated_bool: False repeated_bool: True";
     String goodTextCanonical =
         "repeated_bool: true\n" +
         "repeated_bool: false\n" +
         "repeated_bool: false\n" +
+        "repeated_bool: true\n" +
+        "repeated_bool: false\n" +
         "repeated_bool: true\n";
     TestAllTypes.Builder builder = TestAllTypes.newBuilder();
     TextFormat.merge(goodText, builder);
diff --git a/java/core/src/test/java/com/google/protobuf/UnknownFieldSetTest.java b/java/core/src/test/java/com/google/protobuf/UnknownFieldSetTest.java
index 8c9dcafe..32380f70 100644
--- a/java/core/src/test/java/com/google/protobuf/UnknownFieldSetTest.java
+++ b/java/core/src/test/java/com/google/protobuf/UnknownFieldSetTest.java
@@ -50,6 +50,7 @@ import java.util.Map;
  * @author kenton@google.com (Kenton Varda)
  */
 public class UnknownFieldSetTest extends TestCase {
+  @Override
   public void setUp() throws Exception {
     descriptor = TestAllTypes.getDescriptor();
     allFields = TestUtil.getAllSet();
diff --git a/java/core/src/test/java/com/google/protobuf/WireFormatTest.java b/java/core/src/test/java/com/google/protobuf/WireFormatTest.java
index b3aabb8f..e66b371c 100644
--- a/java/core/src/test/java/com/google/protobuf/WireFormatTest.java
+++ b/java/core/src/test/java/com/google/protobuf/WireFormatTest.java
@@ -132,7 +132,7 @@ public class WireFormatTest extends TestCase {
     // so if we serialize a TestAllExtensions then parse it as TestAllTypes
     // it should work.
 
-    TestAllExtensionsLite message = TestUtil.getAllLiteExtensionsSet();
+    TestAllExtensionsLite message = TestUtilLite.getAllLiteExtensionsSet();
     ByteString rawBytes = message.toByteString();
     assertEquals(rawBytes.size(), message.getSerializedSize());
 
@@ -144,7 +144,7 @@ public class WireFormatTest extends TestCase {
   public void testSerializePackedExtensionsLite() throws Exception {
     // TestPackedTypes and TestPackedExtensions should have compatible wire
     // formats; check that they serialize to the same string.
-    TestPackedExtensionsLite message = TestUtil.getLitePackedExtensionsSet();
+    TestPackedExtensionsLite message = TestUtilLite.getLitePackedExtensionsSet();
     ByteString rawBytes = message.toByteString();
 
     TestPackedTypes message2 = TestUtil.getPackedSet();
@@ -190,7 +190,7 @@ public class WireFormatTest extends TestCase {
     TestAllTypes message = TestUtil.getAllSet();
     ByteString rawBytes = message.toByteString();
 
-    ExtensionRegistryLite registry_lite = TestUtil.getExtensionRegistryLite();
+    ExtensionRegistryLite registry_lite = TestUtilLite.getExtensionRegistryLite();
 
     TestAllExtensionsLite message2 =
       TestAllExtensionsLite.parseFrom(rawBytes, registry_lite);
@@ -208,10 +208,10 @@ public class WireFormatTest extends TestCase {
 
   public void testParsePackedExtensionsLite() throws Exception {
     // Ensure that packed extensions can be properly parsed.
-    TestPackedExtensionsLite message = TestUtil.getLitePackedExtensionsSet();
+    TestPackedExtensionsLite message = TestUtilLite.getLitePackedExtensionsSet();
     ByteString rawBytes = message.toByteString();
 
-    ExtensionRegistryLite registry = TestUtil.getExtensionRegistryLite();
+    ExtensionRegistryLite registry = TestUtilLite.getExtensionRegistryLite();
 
     TestPackedExtensionsLite message2 =
         TestPackedExtensionsLite.parseFrom(rawBytes, registry);
diff --git a/java/core/src/test/proto/com/google/protobuf/lite_equals_and_hash.proto b/java/core/src/test/proto/com/google/protobuf/lite_equals_and_hash.proto
index f75484de..6eef42c5 100644
--- a/java/core/src/test/proto/com/google/protobuf/lite_equals_and_hash.proto
+++ b/java/core/src/test/proto/com/google/protobuf/lite_equals_and_hash.proto
@@ -34,9 +34,6 @@ syntax = "proto2";
 
 package protobuf_unittest.lite_equals_and_hash;
 
-// This proto definition is used to test that java_generate_equals_and_hash
-// works correctly with the LITE_RUNTIME.
-option java_generate_equals_and_hash = true;
 option optimize_for = LITE_RUNTIME;
 
 message TestOneofEquals {