Integrate google internal changes.

61 files changed, 5280 insertions, 1778 deletions

diff --git a/java/core/src/main/java/com/google/protobuf/ByteBufferWriter.java b/java/core/src/main/java/com/google/protobuf/ByteBufferWriter.java
new file mode 100644
index 00000000..0cc38175
--- /dev/null
+++ b/java/core/src/main/java/com/google/protobuf/ByteBufferWriter.java
@@ -0,0 +1,145 @@
+// 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 java.lang.Math.max;
+import static java.lang.Math.min;
+
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.lang.ref.SoftReference;
+import java.nio.ByteBuffer;
+
+/**
+ * Utility class to provide efficient writing of {@link ByteBuffer}s to {@link OutputStream}s.
+ */
+final class ByteBufferWriter {
+  private ByteBufferWriter() {}
+
+  /**
+   * Minimum size for a cached buffer. This prevents us from allocating buffers that are too
+   * small to be easily reused.
+   */
+  // TODO(nathanmittler): tune this property or allow configuration?
+  private static final int MIN_CACHED_BUFFER_SIZE = 1024;
+
+  /**
+   * Maximum size for a cached buffer. If a larger buffer is required, it will be allocated
+   * but not cached.
+   */
+  // TODO(nathanmittler): tune this property or allow configuration?
+  private static final int MAX_CACHED_BUFFER_SIZE = 16 * 1024;
+
+  /**
+   * The fraction of the requested buffer size under which the buffer will be reallocated.
+   */
+  // TODO(nathanmittler): tune this property or allow configuration?
+  private static final float BUFFER_REALLOCATION_THRESHOLD = 0.5f;
+
+  /**
+   * Keeping a soft reference to a thread-local buffer. This buffer is used for writing a
+   * {@link ByteBuffer} to an {@link OutputStream} when no zero-copy alternative was available.
+   * Using a "soft" reference since VMs may keep this reference around longer than "weak"
+   * (e.g. HotSpot will maintain soft references until memory pressure warrants collection).
+   */
+  private static final ThreadLocal<SoftReference<byte[]>> BUFFER =
+      new ThreadLocal<SoftReference<byte[]>>();
+
+  /**
+   * For testing purposes only. Clears the cached buffer to force a new allocation on the next
+   * invocation.
+   */
+  static void clearCachedBuffer() {
+    BUFFER.set(null);
+  }
+
+  /**
+   * Writes the remaining content of the buffer to the given stream. The buffer {@code position}
+   * will remain unchanged by this method.
+   */
+  static void write(ByteBuffer buffer, OutputStream output) throws IOException {
+    final int initialPos = buffer.position();
+    try {
+      if (buffer.hasArray()) {
+        // Optimized write for array-backed buffers.
+        // Note that we're taking the risk that a malicious OutputStream could modify the array.
+        output.write(buffer.array(), buffer.arrayOffset() + buffer.position(), buffer.remaining());
+      } else if (output instanceof FileOutputStream) {
+        // Use a channel to write out the ByteBuffer. This will automatically empty the buffer.
+        ((FileOutputStream) output).getChannel().write(buffer);
+      } else {
+        // Read all of the data from the buffer to an array.
+        // TODO(nathanmittler): Consider performance improvements for other "known" stream types.
+        final byte[] array = getOrCreateBuffer(buffer.remaining());
+        while (buffer.hasRemaining()) {
+          int length = min(buffer.remaining(), array.length);
+          buffer.get(array, 0, length);
+          output.write(array, 0, length);
+        }
+      }
+    } finally {
+      // Restore the initial position.
+      buffer.position(initialPos);
+    }
+  }
+
+  private static byte[] getOrCreateBuffer(int requestedSize) {
+    requestedSize = max(requestedSize, MIN_CACHED_BUFFER_SIZE);
+
+    byte[] buffer = getBuffer();
+    // Only allocate if we need to.
+    if (buffer == null || needToReallocate(requestedSize, buffer.length)) {
+      buffer = new byte[requestedSize];
+
+      // Only cache the buffer if it's not too big.
+      if (requestedSize <= MAX_CACHED_BUFFER_SIZE) {
+        setBuffer(buffer);
+      }
+    }
+    return buffer;
+  }
+
+  private static boolean needToReallocate(int requestedSize, int bufferLength) {
+    // First check against just the requested length to avoid the multiply.
+    return bufferLength < requestedSize
+        && bufferLength < requestedSize * BUFFER_REALLOCATION_THRESHOLD;
+  }
+
+  private static byte[] getBuffer() {
+    SoftReference<byte[]> sr = BUFFER.get();
+    return sr == null ? null : sr.get();
+  }
+
+  private static void setBuffer(byte[] value) {
+    BUFFER.set(new SoftReference<byte[]>(value));
+  }
+}
diff --git a/java/core/src/main/java/com/google/protobuf/ByteOutput.java b/java/core/src/main/java/com/google/protobuf/ByteOutput.java
new file mode 100644
index 00000000..8b7b04c8
--- /dev/null
+++ b/java/core/src/main/java/com/google/protobuf/ByteOutput.java
@@ -0,0 +1,116 @@
+// 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 java.io.IOException;
+import java.nio.ByteBuffer;
+
+/**
+ * An output target for raw bytes. This interface provides semantics that support two types of
+ * writing:
+ *
+ * <p/><b>Traditional write operations:</b>
+ * (as defined by {@link java.io.OutputStream}) where the target method is responsible for either
+ * copying the data or completing the write before returning from the method call.
+ *
+ * <p/><b>Lazy write operations:</b> where the caller guarantees that it will never modify the
+ * provided buffer and it can therefore be considered immutable. The target method is free to
+ * maintain a reference to the buffer beyond the scope of the method call (e.g. until the write
+ * operation completes).
+ */
+@ExperimentalApi
+public abstract class ByteOutput {
+  /**
+   * Writes a single byte.
+   *
+   * @param value the byte to be written
+   * @throws IOException thrown if an error occurred while writing
+   */
+  public abstract void write(byte value) throws IOException;
+
+  /**
+   * Writes a sequence of bytes. The {@link ByteOutput} must copy {@code value} if it will
+   * not be processed prior to the return of this method call, since {@code value} may be
+   * reused/altered by the caller.
+   *
+   * <p>NOTE: This method <strong>MUST NOT</strong> modify the {@code value}. Doing so is a
+   * programming error and will lead to data corruption which will be difficult to debug.
+   *
+   * @param value the bytes to be written
+   * @param offset the offset of the start of the writable range
+   * @param length the number of bytes to write starting from {@code offset}
+   * @throws IOException thrown if an error occurred while writing
+   */
+  public abstract void write(byte[] value, int offset, int length) throws IOException;
+
+  /**
+   * Writes a sequence of bytes. The {@link ByteOutput} is free to retain a reference to the value
+   * beyond the scope of this method call (e.g. write later) since it is considered immutable and is
+   * guaranteed not to change by the caller.
+   *
+   * <p>NOTE: This method <strong>MUST NOT</strong> modify the {@code value}. Doing so is a
+   * programming error and will lead to data corruption which will be difficult to debug.
+   *
+   * @param value the bytes to be written
+   * @param offset the offset of the start of the writable range
+   * @param length the number of bytes to write starting from {@code offset}
+   * @throws IOException thrown if an error occurred while writing
+   */
+  public abstract void writeLazy(byte[] value, int offset, int length) throws IOException;
+
+  /**
+   * Writes a sequence of bytes. The {@link ByteOutput} must copy {@code value} if it will
+   * not be processed prior to the return of this method call, since {@code value} may be
+   * reused/altered by the caller.
+   *
+   * <p>NOTE: This method <strong>MUST NOT</strong> modify the {@code value}. Doing so is a
+   * programming error and will lead to data corruption which will be difficult to debug.
+   *
+   * @param value the bytes to be written. Upon returning from this call, the {@code position} of
+   * this buffer will be set to the {@code limit}
+   * @throws IOException thrown if an error occurred while writing
+   */
+  public abstract void write(ByteBuffer value) throws IOException;
+
+  /**
+   * Writes a sequence of bytes. The {@link ByteOutput} is free to retain a reference to the value
+   * beyond the scope of this method call (e.g. write later) since it is considered immutable and is
+   * guaranteed not to change by the caller.
+   *
+   * <p>NOTE: This method <strong>MUST NOT</strong> modify the {@code value}. Doing so is a
+   * programming error and will lead to data corruption which will be difficult to debug.
+   *
+   * @param value the bytes to be written. Upon returning from this call, the {@code position} of
+   * this buffer will be set to the {@code limit}
+   * @throws IOException thrown if an error occurred while writing
+   */
+  public abstract void writeLazy(ByteBuffer value) throws IOException;
+}
diff --git a/java/core/src/main/java/com/google/protobuf/ByteString.java b/java/core/src/main/java/com/google/protobuf/ByteString.java
index 305236f3..62c94508 100644
--- a/java/core/src/main/java/com/google/protobuf/ByteString.java
+++ b/java/core/src/main/java/com/google/protobuf/ByteString.java
@@ -1,4 +1,32 @@
-// Copyright 2007 Google Inc.  All rights reserved.
+// 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;
 
@@ -15,6 +43,7 @@ import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
 import java.nio.charset.UnsupportedCharsetException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
@@ -58,6 +87,54 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
    * Empty {@code ByteString}.
    */
   public static final ByteString EMPTY = new LiteralByteString(Internal.EMPTY_BYTE_ARRAY);
+  
+  /** 
+   * An interface to efficiently copy {@code byte[]}.
+   * 
+   * <p>One of the noticable costs of copying a byte[] into a new array using 
+   * {@code System.arraycopy} is nullification of a new buffer before the copy. It has been shown 
+   * the Hotspot VM is capable to intrisicfy {@code Arrays.copyOfRange} operation to avoid this
+   * expensive nullification and provide substantial performance gain. Unfortunately this does not
+   * hold on Android runtimes and could make the copy slightly slower due to additional code in
+   * the {@code Arrays.copyOfRange}. Thus we provide two different implementation for array copier
+   * for Hotspot and Android runtimes. 
+   */
+  private interface ByteArrayCopier {
+    /**
+     * Copies the specified range of the specified array into a new array
+     */
+    byte[] copyFrom(byte[] bytes, int offset, int size);
+  }
+  
+  /** Implementation of {@code ByteArrayCopier} which uses {@link System#arraycopy}. */
+  private static final class SystemByteArrayCopier implements ByteArrayCopier {
+    @Override
+    public byte[] copyFrom(byte[] bytes, int offset, int size) {
+      byte[] copy = new byte[size];
+      System.arraycopy(bytes, offset, copy, 0, size);
+      return copy;
+    }
+  }
+  
+  /** Implementation of {@code ByteArrayCopier} which uses {@link Arrays#copyOfRange}. */
+  private static final class ArraysByteArrayCopier implements ByteArrayCopier {
+    @Override
+    public byte[] copyFrom(byte[] bytes, int offset, int size) {
+      return Arrays.copyOfRange(bytes, offset, offset + size);
+    }
+  }
+  
+  private static final ByteArrayCopier byteArrayCopier;
+  static {
+    boolean isAndroid = true;
+    try {
+      Class.forName("android.content.Context");
+    } catch (ClassNotFoundException e) {
+      isAndroid = false;
+    }
+    
+    byteArrayCopier = isAndroid ? new SystemByteArrayCopier() : new ArraysByteArrayCopier();
+  }
 
   /**
    * Cached hash value. Intentionally accessed via a data race, which
@@ -77,7 +154,7 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
    *
    * @param index index of byte
    * @return the value
-   * @throws ArrayIndexOutOfBoundsException {@code index < 0 or index >= size}
+   * @throws IndexOutOfBoundsException {@code index < 0 or index >= size}
    */
   public abstract byte byteAt(int index);
 
@@ -109,7 +186,7 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
       public byte nextByte() {
         try {
           return byteAt(position++);
-        } catch (ArrayIndexOutOfBoundsException e) {
+        } catch (IndexOutOfBoundsException e) {
           throw new NoSuchElementException(e.getMessage());
         }
       }
@@ -220,9 +297,7 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
    * @return new {@code ByteString}
    */
   public static ByteString copyFrom(byte[] bytes, int offset, int size) {
-    byte[] copy = new byte[size];
-    System.arraycopy(bytes, offset, copy, 0, size);
-    return new LiteralByteString(copy);
+    return new LiteralByteString(byteArrayCopier.copyFrom(bytes, offset, size));
   }
 
   /**
@@ -559,12 +634,7 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
   }
 
   /**
-   * Writes the complete contents of this byte string to
-   * the specified output stream argument.
-   *
-   * <p>It is assumed that the {@link OutputStream} will not modify the contents passed it
-   * it. It may be possible for a malicious {@link OutputStream} to corrupt
-   * the data underlying the {@link ByteString}.
+   * Writes a copy of the contents of this byte string to the specified output stream argument.
    *
    * @param  out  the output stream to which to write the data.
    * @throws IOException  if an I/O error occurs.
@@ -578,8 +648,7 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
    * @param  sourceOffset offset within these bytes
    * @param  numberToWrite number of bytes to write
    * @throws IOException  if an I/O error occurs.
-   * @throws IndexOutOfBoundsException if an offset or size is negative or too
-   *     large
+   * @throws IndexOutOfBoundsException if an offset or size is negative or too large
    */
   final void writeTo(OutputStream out, int sourceOffset, int numberToWrite)
       throws IOException {
@@ -597,6 +666,20 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
       throws IOException;
 
   /**
+   * Writes this {@link ByteString} to the provided {@link ByteOutput}. Calling
+   * this method may result in multiple operations on the target {@link ByteOutput}.
+   *
+   * <p>This method may expose internal backing buffers of the {@link ByteString} to the {@link
+   * ByteOutput} in order to avoid additional copying overhead. It would be possible for a malicious
+   * {@link ByteOutput} to corrupt the {@link ByteString}. Use with caution!
+   *
+   * @param  byteOutput  the output target to receive the bytes
+   * @throws IOException  if an I/O error occurs
+   * @see UnsafeByteOperations#unsafeWriteTo(ByteString, ByteOutput)
+   */
+  abstract void writeTo(ByteOutput byteOutput) throws IOException;
+
+  /**
    * Constructs a read-only {@code java.nio.ByteBuffer} whose content
    * is equal to the contents of this byte string.
    * The result uses the same backing array as the byte string, if possible.
@@ -1102,7 +1185,7 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
    *
    * @param index the index position to be tested
    * @param size the length of the array
-   * @throws ArrayIndexOutOfBoundsException if the index does not fall within the array.
+   * @throws IndexOutOfBoundsException if the index does not fall within the array.
    */
   static void checkIndex(int index, int size) {
     if ((index | (size - (index + 1))) < 0) {
@@ -1120,7 +1203,7 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
    * @param endIndex the end index of the range (exclusive)
    * @param size the size of the array.
    * @return the length of the range.
-   * @throws ArrayIndexOutOfBoundsException some or all of the range falls outside of the array.
+   * @throws IndexOutOfBoundsException some or all of the range falls outside of the array.
    */
   static int checkRange(int startIndex, int endIndex, int size) {
     final int length = endIndex - startIndex;
@@ -1236,6 +1319,11 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
     }
 
     @Override
+    final void writeTo(ByteOutput output) throws IOException {
+      output.writeLazy(bytes, getOffsetIntoBytes(), size());
+    }
+
+    @Override
     protected final String toStringInternal(Charset charset) {
       return new String(bytes, getOffsetIntoBytes(), size(), charset);
     }
diff --git a/java/core/src/main/java/com/google/protobuf/CodedInputStream.java b/java/core/src/main/java/com/google/protobuf/CodedInputStream.java
index b3118ee0..e8860651 100644
--- a/java/core/src/main/java/com/google/protobuf/CodedInputStream.java
+++ b/java/core/src/main/java/com/google/protobuf/CodedInputStream.java
@@ -55,7 +55,14 @@ public final class CodedInputStream {
    * Create a new CodedInputStream wrapping the given InputStream.
    */
   public static CodedInputStream newInstance(final InputStream input) {
-    return new CodedInputStream(input);
+    return new CodedInputStream(input, BUFFER_SIZE);
+  }
+  
+  /**
+   * Create a new CodedInputStream wrapping the given InputStream.
+   */
+  static CodedInputStream newInstance(final InputStream input, int bufferSize) {
+    return new CodedInputStream(input, bufferSize);
   }
 
   /**
@@ -70,14 +77,14 @@ public final class CodedInputStream {
    */
   public static CodedInputStream newInstance(final byte[] buf, final int off,
                                              final int len) {
-    return newInstance(buf, off, len, false);
+    return newInstance(buf, off, len, false /* bufferIsImmutable */);
   }
-
+  
   /**
    * Create a new CodedInputStream wrapping the given byte array slice.
    */
-  public static CodedInputStream newInstance(final byte[] buf, final int off,
-                                             final int len, boolean bufferIsImmutable) {
+  static CodedInputStream newInstance(
+      final byte[] buf, final int off, final int len, final boolean bufferIsImmutable) {
     CodedInputStream result = new CodedInputStream(buf, off, len, bufferIsImmutable);
     try {
       // Some uses of CodedInputStream can be more efficient if they know
@@ -361,6 +368,11 @@ public final class CodedInputStream {
       return result;
     } else if (size == 0) {
       return "";
+    } else if (size <= bufferSize) {
+      refillBuffer(size);
+      String result = new String(buffer, bufferPos, size, Internal.UTF_8);
+      bufferPos += size;
+      return result;
     } else {
       // Slow path:  Build a byte array first then copy it.
       return new String(readRawBytesSlowPath(size), Internal.UTF_8);
@@ -375,14 +387,21 @@ public final class CodedInputStream {
   public String readStringRequireUtf8() throws IOException {
     final int size = readRawVarint32();
     final byte[] bytes;
-    int pos = bufferPos;
-    if (size <= (bufferSize - pos) && size > 0) {
+    final int oldPos = bufferPos;
+    final int pos;
+    if (size <= (bufferSize - oldPos) && size > 0) {
       // Fast path:  We already have the bytes in a contiguous buffer, so
       //   just copy directly from it.
       bytes = buffer;
-      bufferPos = pos + size;
+      bufferPos = oldPos + size;
+      pos = oldPos;
     } else if (size == 0) {
       return "";
+    } else if (size <= bufferSize) {
+      refillBuffer(size);
+      bytes = buffer;
+      pos = 0;
+      bufferPos = pos + size;
     } else {
       // Slow path:  Build a byte array first then copy it.
       bytes = readRawBytesSlowPath(size);
@@ -869,7 +888,8 @@ public final class CodedInputStream {
   private static final int DEFAULT_SIZE_LIMIT = 64 << 20;  // 64MB
   private static final int BUFFER_SIZE = 4096;
 
-  private CodedInputStream(final byte[] buffer, final int off, final int len, boolean bufferIsImmutable) {
+  private CodedInputStream(
+      final byte[] buffer, final int off, final int len, boolean bufferIsImmutable) {
     this.buffer = buffer;
     bufferSize = off + len;
     bufferPos = off;
@@ -878,8 +898,8 @@ public final class CodedInputStream {
     this.bufferIsImmutable = bufferIsImmutable;
   }
 
-  private CodedInputStream(final InputStream input) {
-    buffer = new byte[BUFFER_SIZE];
+  private CodedInputStream(final InputStream input, int bufferSize) {
+    buffer = new byte[bufferSize];
     bufferSize = 0;
     bufferPos = 0;
     totalBytesRetired = 0;
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 d8ebad21..b92394b8 100644
--- a/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
+++ b/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
@@ -49,13 +49,17 @@ import java.util.logging.Logger;
  * you are writing some other format of your own design, use the latter.
  *
  * <p>This class is totally unsynchronized.
- *
- * @author kneton@google.com Kenton Varda
  */
 public final class CodedOutputStream {
-
   private static final Logger logger = Logger.getLogger(CodedOutputStream.class.getName());
 
+  private static final int LITTLE_ENDIAN_64_SIZE = 8;
+
+  /**
+   * @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;
@@ -77,12 +81,13 @@ public final class CodedOutputStream {
    *         CodedOutputStream.
    */
   static int computePreferredBufferSize(int dataLength) {
-    if (dataLength > DEFAULT_BUFFER_SIZE) return DEFAULT_BUFFER_SIZE;
+    if (dataLength > DEFAULT_BUFFER_SIZE) {
+      return DEFAULT_BUFFER_SIZE;
+    }
     return dataLength;
   }
 
-  private CodedOutputStream(final byte[] buffer, final int offset,
-                            final int length) {
+  private CodedOutputStream(final byte[] buffer, final int offset, final int length) {
     output = null;
     this.buffer = buffer;
     position = offset;
@@ -108,8 +113,7 @@ public final class CodedOutputStream {
    * Create a new {@code CodedOutputStream} wrapping the given
    * {@code OutputStream} with a given buffer size.
    */
-  public static CodedOutputStream newInstance(final OutputStream output,
-      final int bufferSize) {
+  public static CodedOutputStream newInstance(final OutputStream output, final int bufferSize) {
     return new CodedOutputStream(output, new byte[bufferSize]);
   }
 
@@ -131,9 +135,8 @@ public final class CodedOutputStream {
    * array is faster than writing to an {@code OutputStream}.  See also
    * {@link ByteString#newCodedBuilder}.
    */
-  public static CodedOutputStream newInstance(final byte[] flatArray,
-                                              final int offset,
-                                              final int length) {
+  public static CodedOutputStream newInstance(
+      final byte[] flatArray, final int offset, final int length) {
     return new CodedOutputStream(flatArray, offset, length);
   }
 
@@ -147,13 +150,13 @@ public final class CodedOutputStream {
   /**
    * Create a new {@code CodedOutputStream} that writes to the given ByteBuffer.
    */
-  public static CodedOutputStream newInstance(ByteBuffer byteBuffer,
-      int bufferSize) {
+  public static CodedOutputStream newInstance(ByteBuffer byteBuffer, int bufferSize) {
     return newInstance(new ByteBufferOutputStream(byteBuffer), bufferSize);
   }
 
   private static class ByteBufferOutputStream extends OutputStream {
     private final ByteBuffer byteBuffer;
+
     public ByteBufferOutputStream(ByteBuffer byteBuffer) {
       this.byteBuffer = byteBuffer;
     }
@@ -171,106 +174,120 @@ public final class CodedOutputStream {
 
   // -----------------------------------------------------------------
 
-  /** 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);
+  /** Encode and write a tag. */
+  public void writeTag(final int fieldNumber, final int wireType) throws IOException {
+    writeRawVarint32(WireFormat.makeTag(fieldNumber, wireType));
   }
 
-  /** 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);
+  /** 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);
   }
 
-  /** Write a {@code uint64} field, including tag, to the stream. */
-  public void writeUInt64(final int fieldNumber, final long 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);
-    writeUInt64NoTag(value);
+    writeUInt32NoTag(value);
+  }
+
+  /** 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);
+  }
+
+  /** 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);
+  }
+
+  /** 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);
   }
 
   /** Write an {@code int64} field, including tag, to the stream. */
-  public void writeInt64(final int fieldNumber, final long value)
-                         throws IOException {
+  public void writeInt64(final int fieldNumber, final long value) throws IOException {
     writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
     writeInt64NoTag(value);
   }
 
-  /** Write an {@code int32} field, including tag, to the stream. */
-  public void writeInt32(final int fieldNumber, final int value)
-                         throws IOException {
+  /** 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);
-    writeInt32NoTag(value);
+    writeUInt64NoTag(value);
+  }
+
+  /** 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);
   }
 
   /** Write a {@code fixed64} field, including tag, to the stream. */
-  public void writeFixed64(final int fieldNumber, final long value)
-                           throws IOException {
+  public void writeFixed64(final int fieldNumber, final long value) throws IOException {
     writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
     writeFixed64NoTag(value);
   }
 
-  /** Write a {@code fixed32} field, including tag, to the stream. */
-  public void writeFixed32(final int fieldNumber, final int 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);
+  }
+
+  /** 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);
-    writeFixed32NoTag(value);
+    writeFloatNoTag(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);
   }
 
   /** Write a {@code bool} field, including tag, to the stream. */
-  public void writeBool(final int fieldNumber, final boolean value)
-                        throws IOException {
+  public void writeBool(final int fieldNumber, final boolean value) throws IOException {
     writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
     writeBoolNoTag(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);
-  }
-
-  /** Write a {@code group} field, including tag, to the stream. */
-  public void writeGroup(final int fieldNumber, final MessageLite value)
-                         throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_START_GROUP);
-    writeGroupNoTag(value);
-    writeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP);
+  /**
+   * 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);
   }
 
-
-  /** Write an embedded message field, including tag, to the stream. */
-  public void writeMessage(final int fieldNumber, final MessageLite value)
-                           throws IOException {
+  /** 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);
-    writeMessageNoTag(value);
+    writeStringNoTag(value);
   }
 
-
   /** Write a {@code bytes} field, including tag, to the stream. */
-  public void writeBytes(final int fieldNumber, final ByteString value)
-                         throws IOException {
+  public void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
     writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
     writeBytesNoTag(value);
   }
 
   /** Write a {@code bytes} field, including tag, to the stream. */
-  public void writeByteArray(final int fieldNumber, final byte[] value)
-                             throws IOException {
+  public void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
     writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
     writeByteArrayNoTag(value);
   }
 
   /** 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 {
+  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);
   }
@@ -285,64 +302,100 @@ 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 {
+  public void writeByteBuffer(final int fieldNumber, final ByteBuffer value) throws IOException {
     writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
     writeByteBufferNoTag(value);
   }
 
-  /** 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);
+  /** Write a single byte. */
+  public void writeRawByte(final byte value) throws IOException {
+    if (position == limit) {
+      refreshBuffer();
+    }
+
+    buffer[position++] = value;
+    ++totalBytesWritten;
   }
 
-  /**
-   * Write an enum field, including tag, to the stream.  Caller is responsible
-   * for converting the enum value to its numeric value.
-   */
-  public void writeEnum(final int fieldNumber, final int value)
-                        throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeEnumNoTag(value);
+  /** Write a single byte, represented by an integer value. */
+  public void writeRawByte(final int value) throws IOException {
+    writeRawByte((byte) value);
   }
 
-  /** 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);
+  /** Write an array of bytes. */
+  public void writeRawBytes(final byte[] value) throws IOException {
+    writeRawBytes(value, 0, value.length);
   }
 
-  /** 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);
+  /** 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 an {@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);
+  /** Write a byte string. */
+  public void writeRawBytes(final ByteString value) throws IOException {
+    writeRawBytes(value, 0, value.size());
   }
 
-  /** 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);
+  /**
+   * Write a ByteBuffer. 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 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);
+    }
+  }
+
+  /** 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);
   }
 
   /**
    * 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 {
+  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);
@@ -353,9 +406,8 @@ public final class CodedOutputStream {
    * 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 {
+  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);
@@ -364,19 +416,34 @@ public final class CodedOutputStream {
 
   // -----------------------------------------------------------------
 
-  /** Write a {@code double} field to the stream. */
-  public void writeDoubleNoTag(final double value) throws IOException {
-    writeRawLittleEndian64(Double.doubleToRawLongBits(value));
+  /** 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);
+    }
   }
 
-  /** Write a {@code float} field to the stream. */
-  public void writeFloatNoTag(final float value) throws IOException {
-    writeRawLittleEndian32(Float.floatToRawIntBits(value));
+  /** Write a {@code uint32} field to the stream. */
+  public void writeUInt32NoTag(final int value) throws IOException {
+    writeRawVarint32(value);
   }
 
-  /** Write a {@code uint64} field to the stream. */
-  public void writeUInt64NoTag(final long value) throws IOException {
-    writeRawVarint64(value);
+  /** Write a {@code sint32} field to the stream. */
+  public void writeSInt32NoTag(final int value) throws IOException {
+    writeRawVarint32(encodeZigZag32(value));
+  }
+
+  /** Write a {@code fixed32} field to the stream. */
+  public void writeFixed32NoTag(final int value) throws IOException {
+    writeRawLittleEndian32(value);
+  }
+
+  /** Write a {@code sfixed32} field to the stream. */
+  public void writeSFixed32NoTag(final int value) throws IOException {
+    writeRawLittleEndian32(value);
   }
 
   /** Write an {@code int64} field to the stream. */
@@ -384,14 +451,14 @@ public final class CodedOutputStream {
     writeRawVarint64(value);
   }
 
-  /** 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);
-    }
+  /** Write a {@code uint64} field to the stream. */
+  public void writeUInt64NoTag(final long value) throws IOException {
+    writeRawVarint64(value);
+  }
+
+  /** Write a {@code sint64} field to the stream. */
+  public void writeSInt64NoTag(final long value) throws IOException {
+    writeRawVarint64(encodeZigZag64(value));
   }
 
   /** Write a {@code fixed64} field to the stream. */
@@ -399,9 +466,19 @@ public final class CodedOutputStream {
     writeRawLittleEndian64(value);
   }
 
-  /** Write a {@code fixed32} field to the stream. */
-  public void writeFixed32NoTag(final int value) throws IOException {
-    writeRawLittleEndian32(value);
+  /** Write a {@code sfixed64} field to the stream. */
+  public void writeSFixed64NoTag(final long value) throws IOException {
+    writeRawLittleEndian64(value);
+  }
+
+  /** Write a {@code float} field to the stream. */
+  public void writeFloatNoTag(final float value) throws IOException {
+    writeRawLittleEndian32(Float.floatToRawIntBits(value));
+  }
+
+  /** Write a {@code double} field to the stream. */
+  public void writeDoubleNoTag(final double value) throws IOException {
+    writeRawLittleEndian64(Double.doubleToRawLongBits(value));
   }
 
   /** Write a {@code bool} field to the stream. */
@@ -409,6 +486,14 @@ public final class CodedOutputStream {
     writeRawByte(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 {
+    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 {
@@ -421,89 +506,6 @@ public final class CodedOutputStream {
     }
   }
 
-  /** 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 {@code group} field to the stream. */
-  public void writeGroupNoTag(final MessageLite value) throws IOException {
-    value.writeTo(this);
-  }
-
-
-  /** Write an embedded message field to the stream. */
-  public void writeMessageNoTag(final MessageLite value) throws IOException {
-    writeRawVarint32(value.getSerializedSize());
-    value.writeTo(this);
-  }
-
-
   /** Write a {@code bytes} field to the stream. */
   public void writeBytesNoTag(final ByteString value) throws IOException {
     writeRawVarint32(value.size());
@@ -516,86 +518,53 @@ public final class CodedOutputStream {
     writeRawBytes(value);
   }
 
-  /** Write a {@code bytes} field to the stream. */
-  public void writeByteArrayNoTag(final byte[] value,
-                                  final int offset,
-                                  final int length) throws IOException {
-    writeRawVarint32(length);
-    writeRawBytes(value, offset, length);
+  /** Write an embedded message field to the stream. */
+  public void writeMessageNoTag(final MessageLite value) throws IOException {
+    writeRawVarint32(value.getSerializedSize());
+    value.writeTo(this);
   }
 
+  // =================================================================
+  // =================================================================
+
   /**
-   * 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())}.
+   * Compute the number of bytes that would be needed to encode an
+   * {@code int32} field, including tag.
    */
-  public void writeByteBufferNoTag(final ByteBuffer value) throws IOException {
-    writeRawVarint32(value.capacity());
-    writeRawBytes(value);
-  }
-
-  /** Write a {@code uint32} field to the stream. */
-  public void writeUInt32NoTag(final int value) throws IOException {
-    writeRawVarint32(value);
+  public static int computeInt32Size(final int fieldNumber, final int value) {
+    return computeTagSize(fieldNumber) + computeInt32SizeNoTag(value);
   }
 
   /**
-   * Write an enum field to the stream.  Caller is responsible
-   * for converting the enum value to its numeric value.
+   * Compute the number of bytes that would be needed to encode a
+   * {@code uint32} field, including tag.
    */
-  public void writeEnumNoTag(final int value) throws IOException {
-    writeInt32NoTag(value);
-  }
-
-  /** Write an {@code sfixed32} field to the stream. */
-  public void writeSFixed32NoTag(final int value) throws IOException {
-    writeRawLittleEndian32(value);
-  }
-
-  /** Write an {@code sfixed64} field to the stream. */
-  public void writeSFixed64NoTag(final long value) throws IOException {
-    writeRawLittleEndian64(value);
-  }
-
-  /** Write an {@code sint32} field to the stream. */
-  public void writeSInt32NoTag(final int value) throws IOException {
-    writeRawVarint32(encodeZigZag32(value));
-  }
-
-  /** Write an {@code sint64} field to the stream. */
-  public void writeSInt64NoTag(final long value) throws IOException {
-    writeRawVarint64(encodeZigZag64(value));
+  public static int computeUInt32Size(final int fieldNumber, final int value) {
+    return computeTagSize(fieldNumber) + computeUInt32SizeNoTag(value);
   }
 
-  // =================================================================
-
   /**
-   * Compute the number of bytes that would be needed to encode a
-   * {@code double} field, including tag.
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sint32} field, including tag.
    */
-  public static int computeDoubleSize(final int fieldNumber,
-                                      final double value) {
-    return computeTagSize(fieldNumber) + computeDoubleSizeNoTag(value);
+  public static int computeSInt32Size(final int fieldNumber, final int value) {
+    return computeTagSize(fieldNumber) + computeSInt32SizeNoTag(value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
-   * {@code float} field, including tag.
+   * {@code fixed32} field, including tag.
    */
-  public static int computeFloatSize(final int fieldNumber, final float value) {
-    return computeTagSize(fieldNumber) + computeFloatSizeNoTag(value);
+  public static int computeFixed32Size(final int fieldNumber, final int value) {
+    return computeTagSize(fieldNumber) + computeFixed32SizeNoTag(value);
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode a
-   * {@code uint64} field, including tag.
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sfixed32} field, including tag.
    */
-  public static int computeUInt64Size(final int fieldNumber, final long value) {
-    return computeTagSize(fieldNumber) + computeUInt64SizeNoTag(value);
+  public static int computeSFixed32Size(final int fieldNumber, final int value) {
+    return computeTagSize(fieldNumber) + computeSFixed32SizeNoTag(value);
   }
 
   /**
@@ -607,73 +576,83 @@ public final class CodedOutputStream {
   }
 
   /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code uint64} field, including tag.
+   */
+  public static int computeUInt64Size(final int fieldNumber, final long value) {
+    return computeTagSize(fieldNumber) + computeUInt64SizeNoTag(value);
+  }
+
+  /**
    * Compute the number of bytes that would be needed to encode an
-   * {@code int32} field, including tag.
+   * {@code sint64} field, including tag.
    */
-  public static int computeInt32Size(final int fieldNumber, final int value) {
-    return computeTagSize(fieldNumber) + computeInt32SizeNoTag(value);
+  public static int computeSInt64Size(final int fieldNumber, final long value) {
+    return computeTagSize(fieldNumber) + computeSInt64SizeNoTag(value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
    * {@code fixed64} field, including tag.
    */
-  public static int computeFixed64Size(final int fieldNumber,
-                                       final long value) {
+  public static int computeFixed64Size(final int fieldNumber, final long value) {
     return computeTagSize(fieldNumber) + computeFixed64SizeNoTag(value);
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode a
-   * {@code fixed32} field, including tag.
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sfixed64} field, including tag.
    */
-  public static int computeFixed32Size(final int fieldNumber,
-                                       final int value) {
-    return computeTagSize(fieldNumber) + computeFixed32SizeNoTag(value);
+  public static int computeSFixed64Size(final int fieldNumber, final long value) {
+    return computeTagSize(fieldNumber) + computeSFixed64SizeNoTag(value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
-   * {@code bool} field, including tag.
+   * {@code float} field, including tag.
    */
-  public static int computeBoolSize(final int fieldNumber,
-                                    final boolean value) {
-    return computeTagSize(fieldNumber) + computeBoolSizeNoTag(value);
+  public static int computeFloatSize(final int fieldNumber, final float value) {
+    return computeTagSize(fieldNumber) + computeFloatSizeNoTag(value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
-   * {@code string} field, including tag.
+   * {@code double} field, including tag.
    */
-  public static int computeStringSize(final int fieldNumber,
-                                      final String value) {
-    return computeTagSize(fieldNumber) + computeStringSizeNoTag(value);
+  public static int computeDoubleSize(final int fieldNumber, final double value) {
+    return computeTagSize(fieldNumber) + computeDoubleSizeNoTag(value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
-   * {@code group} field, including tag.
+   * {@code bool} field, including tag.
    */
-  public static int computeGroupSize(final int fieldNumber,
-                                     final MessageLite value) {
-    return computeTagSize(fieldNumber) * 2 + computeGroupSizeNoTag(value);
+  public static int computeBoolSize(final int fieldNumber, final boolean value) {
+    return computeTagSize(fieldNumber) + computeBoolSizeNoTag(value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode an
-   * embedded message field, including tag.
+   * enum field, including tag. The provided value is the numeric
+   * value used to represent the enum value on the wire (not the enum ordinal value).
    */
-  public static int computeMessageSize(final int fieldNumber,
-                                       final MessageLite value) {
-    return computeTagSize(fieldNumber) + computeMessageSizeNoTag(value);
+  public static int computeEnumSize(final int fieldNumber, final int value) {
+    return computeTagSize(fieldNumber) + computeEnumSizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code string} field, including tag.
+   */
+  public static int computeStringSize(final int fieldNumber, final String value) {
+    return computeTagSize(fieldNumber) + computeStringSizeNoTag(value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
    * {@code bytes} field, including tag.
    */
-  public static int computeBytesSize(final int fieldNumber,
-                                     final ByteString value) {
+  public static int computeBytesSize(final int fieldNumber, final ByteString value) {
     return computeTagSize(fieldNumber) + computeBytesSizeNoTag(value);
   }
 
@@ -681,8 +660,7 @@ public final class CodedOutputStream {
    * Compute the number of bytes that would be needed to encode a
    * {@code bytes} field, including tag.
    */
-  public static int computeByteArraySize(final int fieldNumber,
-                                         final byte[] value) {
+  public static int computeByteArraySize(final int fieldNumber, final byte[] value) {
     return computeTagSize(fieldNumber) + computeByteArraySizeNoTag(value);
   }
 
@@ -690,8 +668,7 @@ public final class CodedOutputStream {
    * Compute the number of bytes that would be needed to encode a
    * {@code bytes} field, including tag.
    */
-  public static int computeByteBufferSize(final int fieldNumber,
-                                         final ByteBuffer value) {
+  public static int computeByteBufferSize(final int fieldNumber, final ByteBuffer value) {
     return computeTagSize(fieldNumber) + computeByteBufferSizeNoTag(value);
   }
 
@@ -699,114 +676,111 @@ public final class CodedOutputStream {
    * Compute the number of bytes that would be needed to encode an
    * embedded message in lazy field, including tag.
    */
-  public static int computeLazyFieldSize(final int fieldNumber,
-                                         final LazyFieldLite value) {
+  public static int computeLazyFieldSize(final int fieldNumber, final LazyFieldLite value) {
     return computeTagSize(fieldNumber) + computeLazyFieldSizeNoTag(value);
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode a
-   * {@code uint32} field, including tag.
+   * Compute the number of bytes that would be needed to encode an
+   * embedded message field, including tag.
    */
-  public static int computeUInt32Size(final int fieldNumber, final int value) {
-    return computeTagSize(fieldNumber) + computeUInt32SizeNoTag(value);
+  public static int computeMessageSize(final int fieldNumber, final MessageLite value) {
+    return computeTagSize(fieldNumber) + computeMessageSizeNoTag(value);
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode an
-   * enum field, including tag.  Caller is responsible for converting the
-   * enum value to its numeric value.
+   * Compute the number of bytes that would be needed to encode a
+   * MessageSet extension to the stream.  For historical reasons,
+   * the wire format differs from normal fields.
    */
-  public static int computeEnumSize(final int fieldNumber, final int value) {
-    return computeTagSize(fieldNumber) + computeEnumSizeNoTag(value);
+  public static int computeMessageSetExtensionSize(final int fieldNumber, final MessageLite value) {
+    return computeTagSize(WireFormat.MESSAGE_SET_ITEM) * 2
+        + computeUInt32Size(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber)
+        + computeMessageSize(WireFormat.MESSAGE_SET_MESSAGE, value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode an
-   * {@code sfixed32} field, including tag.
+   * unparsed MessageSet extension field to the stream.  For
+   * historical reasons, the wire format differs from normal fields.
    */
-  public static int computeSFixed32Size(final int fieldNumber,
-                                        final int value) {
-    return computeTagSize(fieldNumber) + computeSFixed32SizeNoTag(value);
+  public static int computeRawMessageSetExtensionSize(
+      final int fieldNumber, final ByteString value) {
+    return computeTagSize(WireFormat.MESSAGE_SET_ITEM) * 2
+        + computeUInt32Size(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber)
+        + computeBytesSize(WireFormat.MESSAGE_SET_MESSAGE, value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode an
-   * {@code sfixed64} field, including tag.
+   * lazily parsed MessageSet extension field to the stream.  For
+   * historical reasons, the wire format differs from normal fields.
    */
-  public static int computeSFixed64Size(final int fieldNumber,
-                                        final long value) {
-    return computeTagSize(fieldNumber) + computeSFixed64SizeNoTag(value);
+  public static int computeLazyFieldMessageSetExtensionSize(
+      final int fieldNumber, final LazyFieldLite value) {
+    return computeTagSize(WireFormat.MESSAGE_SET_ITEM) * 2
+        + computeUInt32Size(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber)
+        + computeLazyFieldSize(WireFormat.MESSAGE_SET_MESSAGE, value);
   }
 
-  /**
-   * Compute the number of bytes that would be needed to encode an
-   * {@code sint32} field, including tag.
-   */
-  public static int computeSInt32Size(final int fieldNumber, final int value) {
-    return computeTagSize(fieldNumber) + computeSInt32SizeNoTag(value);
+  // -----------------------------------------------------------------
+
+  /** 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));
   }
 
   /**
    * Compute the number of bytes that would be needed to encode an
-   * {@code sint64} field, including tag.
+   * {@code int32} field, including tag.
    */
-  public static int computeSInt64Size(final int fieldNumber, final long value) {
-    return computeTagSize(fieldNumber) + computeSInt64SizeNoTag(value);
+  public static int computeInt32SizeNoTag(final int value) {
+    if (value >= 0) {
+      return computeRawVarint32Size(value);
+    } else {
+      // Must sign-extend.
+      return 10;
+    }
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
-   * MessageSet extension to the stream.  For historical reasons,
-   * the wire format differs from normal fields.
+   * {@code uint32} field.
    */
-  public static int computeMessageSetExtensionSize(
-      final int fieldNumber, final MessageLite value) {
-    return computeTagSize(WireFormat.MESSAGE_SET_ITEM) * 2 +
-           computeUInt32Size(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber) +
-           computeMessageSize(WireFormat.MESSAGE_SET_MESSAGE, value);
+  public static int computeUInt32SizeNoTag(final int value) {
+    return computeRawVarint32Size(value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode an
-   * unparsed MessageSet extension field to the stream.  For
-   * historical reasons, the wire format differs from normal fields.
+   * {@code sint32} field.
    */
-  public static int computeRawMessageSetExtensionSize(
-      final int fieldNumber, final ByteString value) {
-    return computeTagSize(WireFormat.MESSAGE_SET_ITEM) * 2 +
-           computeUInt32Size(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber) +
-           computeBytesSize(WireFormat.MESSAGE_SET_MESSAGE, value);
+  public static int computeSInt32SizeNoTag(final int value) {
+    return computeRawVarint32Size(encodeZigZag32(value));
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode an
-   * lazily parsed MessageSet extension field to the stream.  For
-   * historical reasons, the wire format differs from normal fields.
+   * Compute the number of bytes that would be needed to encode a
+   * {@code fixed32} field.
    */
-  public static int computeLazyFieldMessageSetExtensionSize(
-      final int fieldNumber, final LazyFieldLite value) {
-    return computeTagSize(WireFormat.MESSAGE_SET_ITEM) * 2 +
-           computeUInt32Size(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber) +
-           computeLazyFieldSize(WireFormat.MESSAGE_SET_MESSAGE, value);
+  public static int computeFixed32SizeNoTag(@SuppressWarnings("unused") final int unused) {
+    return LITTLE_ENDIAN_32_SIZE;
   }
 
-  // -----------------------------------------------------------------
-
   /**
-   * Compute the number of bytes that would be needed to encode a
-   * {@code double} field, including tag.
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sfixed32} field.
    */
-  public static int computeDoubleSizeNoTag(final double value) {
-    return LITTLE_ENDIAN_64_SIZE;
+  public static int computeSFixed32SizeNoTag(@SuppressWarnings("unused") final int unused) {
+    return LITTLE_ENDIAN_32_SIZE;
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode a
-   * {@code float} field, including tag.
+   * Compute the number of bytes that would be needed to encode an
+   * {@code int64} field, including tag.
    */
-  public static int computeFloatSizeNoTag(final float value) {
-    return LITTLE_ENDIAN_32_SIZE;
+  public static int computeInt64SizeNoTag(final long value) {
+    return computeRawVarint64Size(value);
   }
 
   /**
@@ -819,50 +793,62 @@ public final class CodedOutputStream {
 
   /**
    * Compute the number of bytes that would be needed to encode an
-   * {@code int64} field, including tag.
+   * {@code sint64} field.
    */
-  public static int computeInt64SizeNoTag(final long value) {
-    return computeRawVarint64Size(value);
+  public static int computeSInt64SizeNoTag(final long value) {
+    return computeRawVarint64Size(encodeZigZag64(value));
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode an
-   * {@code int32} field, including tag.
+   * Compute the number of bytes that would be needed to encode a
+   * {@code fixed64} field.
    */
-  public static int computeInt32SizeNoTag(final int value) {
-    if (value >= 0) {
-      return computeRawVarint32Size(value);
-    } else {
-      // Must sign-extend.
-      return 10;
-    }
+  public static int computeFixed64SizeNoTag(@SuppressWarnings("unused") final long unused) {
+    return LITTLE_ENDIAN_64_SIZE;
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode a
-   * {@code fixed64} field.
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sfixed64} field.
    */
-  public static int computeFixed64SizeNoTag(final long value) {
+  public static int computeSFixed64SizeNoTag(@SuppressWarnings("unused") final long unused) {
     return LITTLE_ENDIAN_64_SIZE;
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
-   * {@code fixed32} field.
+   * {@code float} field, including tag.
    */
-  public static int computeFixed32SizeNoTag(final int value) {
+  public static int computeFloatSizeNoTag(@SuppressWarnings("unused") final float unused) {
     return LITTLE_ENDIAN_32_SIZE;
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
+   * {@code double} field, including tag.
+   */
+  public static int computeDoubleSizeNoTag(@SuppressWarnings("unused") final double unused) {
+    return LITTLE_ENDIAN_64_SIZE;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
    * {@code bool} field.
    */
-  public static int computeBoolSizeNoTag(final boolean value) {
+  public static int computeBoolSizeNoTag(@SuppressWarnings("unused") final boolean unused) {
     return 1;
   }
 
   /**
+   * Compute the number of bytes that would be needed to encode an enum field.
+   * The provided value is the numeric value used to represent the enum value on the wire
+   * (not the enum ordinal value).
+   */
+  public static int computeEnumSizeNoTag(final int value) {
+    return computeInt32SizeNoTag(value);
+  }
+
+  /**
    * Compute the number of bytes that would be needed to encode a
    * {@code string} field.
    */
@@ -880,23 +866,6 @@ public final class CodedOutputStream {
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode a
-   * {@code group} field.
-   */
-  public static int computeGroupSizeNoTag(final MessageLite value) {
-    return value.getSerializedSize();
-  }
-
-  /**
-   * Compute the number of bytes that would be needed to encode an embedded
-   * message field.
-   */
-  public static int computeMessageSizeNoTag(final MessageLite value) {
-    final int size = value.getSerializedSize();
-    return computeRawVarint32Size(size) + size;
-  }
-
-  /**
    * Compute the number of bytes that would be needed to encode an embedded
    * message stored in lazy field.
    */
@@ -910,8 +879,7 @@ public final class CodedOutputStream {
    * {@code bytes} field.
    */
   public static int computeBytesSizeNoTag(final ByteString value) {
-    return computeRawVarint32Size(value.size()) +
-           value.size();
+    return computeRawVarint32Size(value.size()) + value.size();
   }
 
   /**
@@ -931,72 +899,47 @@ public final class CodedOutputStream {
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode a
-   * {@code uint32} field.
-   */
-  public static int computeUInt32SizeNoTag(final int value) {
-    return computeRawVarint32Size(value);
-  }
-
-  /**
-   * Compute the number of bytes that would be needed to encode an enum field.
-   * Caller is responsible for converting the enum value to its numeric value.
-   */
-  public static int computeEnumSizeNoTag(final int value) {
-    return computeInt32SizeNoTag(value);
-  }
-
-  /**
-   * Compute the number of bytes that would be needed to encode an
-   * {@code sfixed32} field.
-   */
-  public static int computeSFixed32SizeNoTag(final int value) {
-    return LITTLE_ENDIAN_32_SIZE;
-  }
-
-  /**
-   * Compute the number of bytes that would be needed to encode an
-   * {@code sfixed64} field.
+   * Compute the number of bytes that would be needed to encode an embedded
+   * message field.
    */
-  public static int computeSFixed64SizeNoTag(final long value) {
-    return LITTLE_ENDIAN_64_SIZE;
+  public static int computeMessageSizeNoTag(final MessageLite value) {
+    final int size = value.getSerializedSize();
+    return computeRawVarint32Size(size) + size;
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode an
-   * {@code sint32} field.
+   * Encode a ZigZag-encoded 32-bit value.  ZigZag encodes signed integers
+   * into values that can be efficiently encoded with varint.  (Otherwise,
+   * negative values must be sign-extended to 64 bits to be varint encoded,
+   * thus always taking 10 bytes on the wire.)
+   *
+   * @param n A signed 32-bit integer.
+   * @return An unsigned 32-bit integer, stored in a signed int because
+   *         Java has no explicit unsigned support.
    */
-  public static int computeSInt32SizeNoTag(final int value) {
-    return computeRawVarint32Size(encodeZigZag32(value));
+  public static int encodeZigZag32(final int n) {
+    // Note:  the right-shift must be arithmetic
+    return (n << 1) ^ (n >> 31);
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode an
-   * {@code sint64} field.
+   * Encode a ZigZag-encoded 64-bit value.  ZigZag encodes signed integers
+   * into values that can be efficiently encoded with varint.  (Otherwise,
+   * negative values must be sign-extended to 64 bits to be varint encoded,
+   * thus always taking 10 bytes on the wire.)
+   *
+   * @param n A signed 64-bit integer.
+   * @return An unsigned 64-bit integer, stored in a signed int because
+   *         Java has no explicit unsigned support.
    */
-  public static int computeSInt64SizeNoTag(final long value) {
-    return computeRawVarint64Size(encodeZigZag64(value));
+  public static long encodeZigZag64(final long n) {
+    // Note:  the right-shift must be arithmetic
+    return (n << 1) ^ (n >> 63);
   }
 
   // =================================================================
 
   /**
-   * 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();
-    }
-
-    // Since we have an output stream, this is our buffer
-    // and buffer offset == 0
-    output.write(buffer, 0, position);
-    position = 0;
-  }
-
-  /**
    * Flushes the stream and forces any buffered bytes to be written.  This
    * does not flush the underlying OutputStream.
    */
@@ -1015,8 +958,8 @@ public final class CodedOutputStream {
       return limit - position;
     } else {
       throw new UnsupportedOperationException(
-        "spaceLeft() can only be called on CodedOutputStreams that are " +
-        "writing to a flat array.");
+          "spaceLeft() can only be called on CodedOutputStreams that are "
+              + "writing to a flat array.");
     }
   }
 
@@ -1029,8 +972,7 @@ public final class CodedOutputStream {
    */
   public void checkNoSpaceLeft() {
     if (spaceLeft() != 0) {
-      throw new IllegalStateException(
-        "Did not write as much data as expected.");
+      throw new IllegalStateException("Did not write as much data as expected.");
     }
   }
 
@@ -1063,53 +1005,96 @@ public final class CodedOutputStream {
     return totalBytesWritten;
   }
 
-  /** Write a single byte. */
-  public void writeRawByte(final byte value) throws IOException {
-    if (position == limit) {
-      refreshBuffer();
-    }
-
-    buffer[position++] = value;
-    ++totalBytesWritten;
-  }
+  // =================================================================
 
-  /** Write a single byte, represented by an integer value. */
-  public void writeRawByte(final int value) throws IOException {
-    writeRawByte((byte) value);
-  }
+  /**
+   * 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 byte string. */
-  public void writeRawBytes(final ByteString value) throws IOException {
-    writeRawBytes(value, 0, value.size());
+    // Since we have an output stream, this is our buffer
+    // and buffer offset == 0
+    output.write(buffer, 0, position);
+    position = 0;
   }
 
-  /** Write an array of bytes. */
-  public void writeRawBytes(final byte[] value) throws IOException {
-    writeRawBytes(value, 0, value.length);
+  /** 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 ByteBuffer. 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 writeRawBytes(byteBuffer.slice())}.
+   * 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.
    */
-  public void writeRawBytes(final ByteBuffer value) throws IOException {
-    if (value.hasArray()) {
-      writeRawBytes(value.array(), value.arrayOffset(), value.capacity());
+  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 {
-      ByteBuffer duplicated = value.duplicate();
-      duplicated.clear();
-      writeRawBytesInternal(duplicated);
+      // 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 {
+  private void writeRawBytesInternal(final ByteBuffer value) throws IOException {
     int length = value.remaining();
     if (limit - position >= length) {
       // We have room in the current buffer.
@@ -1143,43 +1128,29 @@ public final class CodedOutputStream {
     }
   }
 
-  /** 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();
+  /** 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);
+  }
 
-      // 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 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. */
-  public void writeRawBytes(final ByteString value, int offset, int length)
-                            throws IOException {
+  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);
@@ -1210,21 +1181,57 @@ public final class CodedOutputStream {
     }
   }
 
-  /** Encode and write a tag. */
-  public void writeTag(final int fieldNumber, final int wireType)
-                       throws IOException {
-    writeRawVarint32(WireFormat.makeTag(fieldNumber, wireType));
+  // =================================================================
+
+  /**
+   * Write a {@code group} field, including tag, to the stream.
+   *
+   * @deprecated groups are deprecated.
+   */
+  @Deprecated
+  public void writeGroup(final int fieldNumber, final MessageLite value) throws IOException {
+    writeTag(fieldNumber, WireFormat.WIRETYPE_START_GROUP);
+    writeGroupNoTag(value);
+    writeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP);
   }
 
-  /** 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));
+  /**
+   * Write a {@code group} field to the stream.
+   *
+   * @deprecated groups are deprecated.
+   */
+  @Deprecated
+  public void writeGroupNoTag(final MessageLite value) throws IOException {
+    value.writeTo(this);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code group} field, including tag.
+   *
+   * @deprecated groups are deprecated.
+   */
+  @Deprecated
+  public static int computeGroupSize(final int fieldNumber, final MessageLite value) {
+    return computeTagSize(fieldNumber) * 2 + computeGroupSizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code group} field.
+   */
+  @Deprecated
+  public static int computeGroupSizeNoTag(final MessageLite value) {
+    return value.getSerializedSize();
   }
 
   /**
    * Encode and write a varint.  {@code value} is treated as
    * unsigned, so it won't be sign-extended if negative.
+   *
+   * @deprecated use {@link #writeUInt32NoTag} instead.
    */
+  @Deprecated
   public void writeRawVarint32(int value) throws IOException {
     while (true) {
       if ((value & ~0x7F) == 0) {
@@ -1238,95 +1245,104 @@ public final class CodedOutputStream {
   }
 
   /**
-   * Compute the number of bytes that would be needed to encode a varint.
-   * {@code value} is treated as unsigned, so it won't be sign-extended if
-   * negative.
+   * Encode and write a varint.
+   *
+   * @deprecated use {@link #writeUInt64NoTag} instead.
    */
-  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;
-  }
-
-  /** Encode and write a varint. */
+  @Deprecated
   public void writeRawVarint64(long value) throws IOException {
     while (true) {
       if ((value & ~0x7FL) == 0) {
-        writeRawByte((int)value);
+        writeRawByte((int) value);
         return;
       } else {
-        writeRawByte(((int)value & 0x7F) | 0x80);
+        writeRawByte(((int) value & 0x7F) | 0x80);
         value >>>= 7;
       }
     }
   }
 
-  /** Compute the number of bytes that would be needed to encode a varint. */
+  /**
+   * Compute the number of bytes that would be needed to encode a varint.
+   * {@code value} is treated as unsigned, so it won't be sign-extended if
+   * negative.
+   *
+   * @deprecated use {@link #computeUInt32SizeNoTag(int)} instead.
+   */
+  @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;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a varint.
+   *
+   * @deprecated use {@link #computeUInt64SizeNoTag(long)} instead.
+   */
+  @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;
+    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; }
+    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;
   }
 
-  /** Write a little-endian 32-bit integer. */
-  public void writeRawLittleEndian32(final int value) throws IOException {
-    writeRawByte((value      ) & 0xFF);
-    writeRawByte((value >>  8) & 0xFF);
-    writeRawByte((value >> 16) & 0xFF);
-    writeRawByte((value >> 24) & 0xFF);
-  }
-
-  public static final int LITTLE_ENDIAN_32_SIZE = 4;
-
-  /** Write a little-endian 64-bit integer. */
-  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 static final int LITTLE_ENDIAN_64_SIZE = 8;
-
   /**
-   * Encode a ZigZag-encoded 32-bit value.  ZigZag encodes signed integers
-   * into values that can be efficiently encoded with varint.  (Otherwise,
-   * negative values must be sign-extended to 64 bits to be varint encoded,
-   * thus always taking 10 bytes on the wire.)
+   * Write a little-endian 32-bit integer.
    *
-   * @param n A signed 32-bit integer.
-   * @return An unsigned 32-bit integer, stored in a signed int because
-   *         Java has no explicit unsigned support.
+   * @deprecated Use {@link #writeFixed32NoTag} instead.
    */
-  public static int encodeZigZag32(final int n) {
-    // Note:  the right-shift must be arithmetic
-    return (n << 1) ^ (n >> 31);
+  @Deprecated
+  public void writeRawLittleEndian32(final int value) throws IOException {
+    writeRawByte((value) & 0xFF);
+    writeRawByte((value >> 8) & 0xFF);
+    writeRawByte((value >> 16) & 0xFF);
+    writeRawByte((value >> 24) & 0xFF);
   }
 
   /**
-   * Encode a ZigZag-encoded 64-bit value.  ZigZag encodes signed integers
-   * into values that can be efficiently encoded with varint.  (Otherwise,
-   * negative values must be sign-extended to 64 bits to be varint encoded,
-   * thus always taking 10 bytes on the wire.)
+   * Write a little-endian 64-bit integer.
    *
-   * @param n A signed 64-bit integer.
-   * @return An unsigned 64-bit integer, stored in a signed int because
-   *         Java has no explicit unsigned support.
+   * @deprecated Use {@link #writeFixed64NoTag} instead.
    */
-  public static long encodeZigZag64(final long n) {
-    // Note:  the right-shift must be arithmetic
-    return (n << 1) ^ (n >> 63);
+  @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);
   }
 }
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 5e15cfbe..e303e138 100644
--- a/java/core/src/main/java/com/google/protobuf/Descriptors.java
+++ b/java/core/src/main/java/com/google/protobuf/Descriptors.java
@@ -272,7 +272,7 @@ public final class Descriptors {
      *           because a field has an undefined type or because two messages
      *           were defined with the same name.
      */
-    private static FileDescriptor buildFrom(
+    public static FileDescriptor buildFrom(
         final FileDescriptorProto proto, final FileDescriptor[] dependencies,
         final boolean allowUnknownDependencies)
         throws DescriptorValidationException {
@@ -1123,7 +1123,7 @@ public final class Descriptors {
       private JavaType javaType;
 
       public FieldDescriptorProto.Type toProto() {
-        return FieldDescriptorProto.Type.valueOf(ordinal() + 1);
+        return FieldDescriptorProto.Type.forNumber(ordinal() + 1);
       }
       public JavaType getJavaType() { return javaType; }
 
diff --git a/java/core/src/main/java/com/google/protobuf/ExperimentalApi.java b/java/core/src/main/java/com/google/protobuf/ExperimentalApi.java
index 6f41fb81..3cd4c884 100644
--- a/java/core/src/main/java/com/google/protobuf/ExperimentalApi.java
+++ b/java/core/src/main/java/com/google/protobuf/ExperimentalApi.java
@@ -1,3 +1,33 @@
+// 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 java.lang.annotation.Documented;
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 ceb97a4e..a50afe55 100644
--- a/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
+++ b/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
@@ -1019,7 +1019,9 @@ public abstract class GeneratedMessage extends AbstractMessage
         verifyContainingType(field);
         final Object value = extensions.getField(field);
         if (value == null) {
-          if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          if (field.isRepeated()) {
+            return Collections.emptyList();
+          } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
             // Lacking an ExtensionRegistry, we have no way to determine the
             // extension's real type, so we return a DynamicMessage.
             return DynamicMessage.getDefaultInstance(field.getMessageType());
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 81e1862c..12a1472d 100644
--- a/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
+++ b/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
@@ -30,6 +30,7 @@
 
 package com.google.protobuf;
 
+import com.google.protobuf.AbstractMessageLite.Builder.LimitedInputStream;
 import com.google.protobuf.Internal.BooleanList;
 import com.google.protobuf.Internal.DoubleList;
 import com.google.protobuf.Internal.FloatList;
@@ -39,6 +40,7 @@ import com.google.protobuf.Internal.ProtobufList;
 import com.google.protobuf.WireFormat.FieldType;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.ObjectStreamException;
 import java.io.Serializable;
 import java.lang.reflect.InvocationTargetException;
@@ -57,10 +59,7 @@ import java.util.Map;
 public abstract class GeneratedMessageLite<
     MessageType extends GeneratedMessageLite<MessageType, BuilderType>,
     BuilderType extends GeneratedMessageLite.Builder<MessageType, BuilderType>> 
-        extends AbstractMessageLite
-        implements Serializable {
-
-  private static final long serialVersionUID = 1L;
+        extends AbstractMessageLite {
 
   /** For use by generated code only. Lazily initialized to reduce allocations. */
   protected UnknownFieldSetLite unknownFields = null;
@@ -83,6 +82,24 @@ public abstract class GeneratedMessageLite<
     return (BuilderType) dynamicMethod(MethodToInvoke.NEW_BUILDER);
   }
 
+  /**
+   * A reflective toString function. This is primarily intended as a developer aid, while keeping
+   * binary size down. The first line of the {@code toString()} representation includes a commented
+   * version of {@code super.toString()} to act as an indicator that this should not be relied on
+   * for comparisons.
+   * <p>
+   * NOTE: This method relies on the field getter methods not being stripped or renamed by proguard.
+   * If they are, the fields will not be included in the returned string representation.
+   * <p>
+   * NOTE: This implementation is liable to change in the future, and should not be relied on in
+   * code.
+   */
+  @Override
+  public String toString() {
+    return MessageLiteToString.toString(this, super.toString());
+  }
+
+
   // 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.
@@ -303,10 +320,9 @@ public abstract class GeneratedMessageLite<
         throws java.io.IOException {
       MessageType parsedMessage = null;
       try {
-        parsedMessage =
-            (MessageType) getDefaultInstanceForType().getParserForType().parsePartialFrom(
-                input, extensionRegistry);
-      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = parsePartialFrom(
+            (MessageType) getDefaultInstanceForType(), input, extensionRegistry);
+      } catch (InvalidProtocolBufferException e) {
         parsedMessage = (MessageType) e.getUnfinishedMessage();
         throw e;
       } finally {
@@ -562,7 +578,6 @@ public abstract class GeneratedMessageLite<
       return extensions.isInitialized();
     }
 
-
     @Override
     protected final void doneParsing() {
       super.doneParsing();
@@ -1049,7 +1064,12 @@ public abstract class GeneratedMessageLite<
    * A serialized (serializable) form of the generated message.  Stores the
    * message as a class name and a byte array.
    */
-  static final class SerializedForm implements Serializable {
+  protected static final class SerializedForm implements Serializable {
+
+    public static SerializedForm of(MessageLite message) {
+      return new SerializedForm(message);
+    }
+    
     private static final long serialVersionUID = 0L;
 
     private final String messageClassName;
@@ -1093,16 +1113,6 @@ public abstract class GeneratedMessageLite<
       }
     }
   }
-
-  /**
-   * Replaces this object in the output stream with a serialized form.
-   * Part of Java's serialization magic.  Generated sub-classes must override
-   * this method by calling {@code return super.writeReplace();}
-   * @return a SerializedForm of this message
-   */
-  protected Object writeReplace() throws ObjectStreamException {
-    return new SerializedForm(this);
-  }
   
   /**
    * Checks that the {@link Extension} is Lite and returns it as a
@@ -1135,45 +1145,6 @@ public abstract class GeneratedMessageLite<
     message.dynamicMethod(MethodToInvoke.MAKE_IMMUTABLE);
   }
   
-  /**
-   * A static helper method for parsing a partial from input using the extension registry and the
-   * instance.
-   */
-  static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
-      T instance, CodedInputStream input, ExtensionRegistryLite extensionRegistry)
-          throws InvalidProtocolBufferException {
-    try {
-      return (T) instance.dynamicMethod(
-          MethodToInvoke.PARSE_PARTIAL_FROM, input, extensionRegistry);
-    } catch (RuntimeException e) {
-      if (e.getCause() instanceof InvalidProtocolBufferException) {
-        throw (InvalidProtocolBufferException) e.getCause();
-      }
-      throw e;
-    }
-  }
-  
-  /**
-   * A {@link Parser} implementation that delegates to the default instance.
-   * <p>
-   * For use by generated code only.
-   */
-  protected static class DefaultInstanceBasedParser<T extends GeneratedMessageLite<T, ?>>
-      extends AbstractParser<T> {
-    
-    private T defaultInstance;
-    
-    public DefaultInstanceBasedParser(T defaultInstance) {
-      this.defaultInstance = defaultInstance;
-    }
-    
-    @Override
-    public T parsePartialFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
-        throws InvalidProtocolBufferException {
-      return GeneratedMessageLite.parsePartialFrom(defaultInstance, input, extensionRegistry);
-    }
-  }
-  
   protected static IntList newIntList() {
     return new IntArrayList();
   }
@@ -1269,8 +1240,218 @@ public abstract class GeneratedMessageLite<
   protected static <E> ProtobufList<E> emptyProtobufList() {
     return ProtobufArrayList.emptyList();
   }
-  
+
   protected static LazyStringArrayList emptyLazyStringArrayList() {
     return LazyStringArrayList.emptyList();
   }
+  
+  /**
+   * A {@link Parser} implementation that delegates to the default instance.
+   * <p>
+   * For use by generated code only.
+   */
+  protected static class DefaultInstanceBasedParser<T extends GeneratedMessageLite<T, ?>>
+      extends AbstractParser<T> {
+    
+    private T defaultInstance;
+    
+    public DefaultInstanceBasedParser(T defaultInstance) {
+      this.defaultInstance = defaultInstance;
+    }
+    
+    @Override
+    public T parsePartialFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      return GeneratedMessageLite.parsePartialFrom(defaultInstance, input, extensionRegistry);
+    }
+  }
+  
+  /**
+   * A static helper method for parsing a partial from input using the extension registry and the
+   * instance.
+   */
+  // TODO(dweis): Should this verify that the last tag was 0?
+  static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
+      T instance, CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+          throws InvalidProtocolBufferException {
+    T result;
+    try {
+      result = (T) instance.dynamicMethod(
+          MethodToInvoke.PARSE_PARTIAL_FROM, input, extensionRegistry);
+    } catch (RuntimeException e) {
+      if (e.getCause() instanceof InvalidProtocolBufferException) {
+        throw (InvalidProtocolBufferException) e.getCause();
+      }
+      throw e;
+    }
+    return result;
+  }
+  
+  protected static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
+      T defaultInstance,
+      CodedInputStream input)
+      throws InvalidProtocolBufferException {
+    return parsePartialFrom(defaultInstance, input, ExtensionRegistryLite.getEmptyRegistry());
+  }
+  
+  /**
+   * Helper method to check if message is initialized.
+   *
+   * @throws InvalidProtocolBufferException if it is not initialized.
+   * @return The message to check.
+   */
+  private static <T extends GeneratedMessageLite<T, ?>> T checkMessageInitialized(T message)
+      throws InvalidProtocolBufferException {
+    if (message != null && !message.isInitialized()) {
+      throw message.newUninitializedMessageException()
+          .asInvalidProtocolBufferException()
+          .setUnfinishedMessage(message);
+    }
+    return message;
+  }
+
+  // Validates last tag.
+  protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
+      T defaultInstance, ByteString data)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parseFrom(defaultInstance, data, ExtensionRegistryLite.getEmptyRegistry()));
+  }
+
+  // Validates last tag.
+  protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
+      T defaultInstance, ByteString data, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(parsePartialFrom(defaultInstance, data, extensionRegistry));
+  }
+  
+  // This is a special case since we want to verify that the last tag is 0. We assume we exhaust the
+  // ByteString.
+  private static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
+      T defaultInstance, ByteString data, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    T message;
+    try {
+      CodedInputStream input = data.newCodedInput();
+      message = parsePartialFrom(defaultInstance, input, extensionRegistry);
+      try {
+        input.checkLastTagWas(0);
+      } catch (InvalidProtocolBufferException e) {
+        throw e.setUnfinishedMessage(message);
+      }
+      return message;
+    } catch (InvalidProtocolBufferException e) {
+      throw e;
+    }
+  }
+  
+  // This is a special case since we want to verify that the last tag is 0. We assume we exhaust the
+  // ByteString.
+  private static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
+      T defaultInstance, byte[] data, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    T message;
+    try {
+      CodedInputStream input = CodedInputStream.newInstance(data);
+      message = parsePartialFrom(defaultInstance, input, extensionRegistry);
+      try {
+        input.checkLastTagWas(0);
+      } catch (InvalidProtocolBufferException e) {
+        throw e.setUnfinishedMessage(message);
+      }
+      return message;
+    } catch (InvalidProtocolBufferException e) {
+      throw e;
+    }
+  }
+
+  // Validates last tag.
+  protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
+      T defaultInstance, byte[] data)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parsePartialFrom(defaultInstance, data, ExtensionRegistryLite.getEmptyRegistry()));
+  }
+
+  // Validates last tag.
+  protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
+      T defaultInstance, byte[] data, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(parsePartialFrom(defaultInstance, data, extensionRegistry));
+  }
+
+  // Does not validate last tag.
+  protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
+      T defaultInstance, InputStream input)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parsePartialFrom(defaultInstance, CodedInputStream.newInstance(input),
+            ExtensionRegistryLite.getEmptyRegistry()));
+  }
+
+  // Does not validate last tag.
+  protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
+      T defaultInstance, InputStream input, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parsePartialFrom(defaultInstance, CodedInputStream.newInstance(input), extensionRegistry));
+  }
+
+  // Does not validate last tag.
+  protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
+      T defaultInstance, CodedInputStream input)
+      throws InvalidProtocolBufferException {
+    return parseFrom(defaultInstance, input, ExtensionRegistryLite.getEmptyRegistry());
+  }
+
+  // Does not validate last tag.
+  protected static <T extends GeneratedMessageLite<T, ?>> T parseFrom(
+      T defaultInstance, CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parsePartialFrom(defaultInstance, input, extensionRegistry));
+  }
+
+  // Validates last tag.
+  protected static <T extends GeneratedMessageLite<T, ?>> T parseDelimitedFrom(
+      T defaultInstance, InputStream input)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parsePartialDelimitedFrom(defaultInstance, input,
+            ExtensionRegistryLite.getEmptyRegistry()));
+  }
+
+  // Validates last tag.
+  protected static <T extends GeneratedMessageLite<T, ?>> T parseDelimitedFrom(
+      T defaultInstance, InputStream input, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parsePartialDelimitedFrom(defaultInstance, input, extensionRegistry));
+  }
+  
+  private static <T extends GeneratedMessageLite<T, ?>> T parsePartialDelimitedFrom(
+      T defaultInstance,
+      InputStream input,
+      ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    int size;
+    try {
+      int firstByte = input.read();
+      if (firstByte == -1) {
+        return null;
+      }
+      size = CodedInputStream.readRawVarint32(firstByte, input);
+    } catch (IOException e) {
+      throw new InvalidProtocolBufferException(e.getMessage());
+    }
+    InputStream limitedInput = new LimitedInputStream(input, size);
+    CodedInputStream codedInput = CodedInputStream.newInstance(limitedInput);
+    T message = parsePartialFrom(defaultInstance, codedInput, extensionRegistry);
+    try {
+      codedInput.checkLastTagWas(0);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(message);
+    }
+    return message;
+  }
 }
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 e19b6dca..abf7ddd6 100644
--- a/java/core/src/main/java/com/google/protobuf/Internal.java
+++ b/java/core/src/main/java/com/google/protobuf/Internal.java
@@ -51,10 +51,12 @@ import java.util.Set;
  *
  * @author kenton@google.com (Kenton Varda)
  */
-public class Internal {
+public final class Internal {
 
-  protected static final Charset UTF_8 = Charset.forName("UTF-8");
-  protected static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
+  private Internal() {}
+
+  static final Charset UTF_8 = Charset.forName("UTF-8");
+  static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
 
   /**
    * Helper called by generated code to construct default values for string
@@ -406,6 +408,7 @@ public class Internal {
   public static final CodedInputStream EMPTY_CODED_INPUT_STREAM =
       CodedInputStream.newInstance(EMPTY_BYTE_ARRAY);
 
+
   /**
    * Provides an immutable view of {@code List<T>} around a {@code List<F>}.
    *
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 5e0a485c..3da8b900 100644
--- a/java/core/src/main/java/com/google/protobuf/LazyField.java
+++ b/java/core/src/main/java/com/google/protobuf/LazyField.java
@@ -39,14 +39,14 @@ import java.util.Map.Entry;
  *
  * Most of key methods are implemented in {@link LazyFieldLite} but this class
  * can contain default instance of the message to provide {@code hashCode()},
- * {@code equals()} and {@code toString()}.
+ * {@code euqals()} and {@code toString()}.
  *
  * @author xiangl@google.com (Xiang Li)
  */
 public class LazyField extends LazyFieldLite {
 
   /**
-   * Carry a message's default instance which is used by {@code hashCode()}, {@code equals()} and
+   * Carry a message's default instance which is used by {@code hashCode()}, {@code euqals()} and
    * {@code toString()}.
    */
   private final MessageLite defaultInstance;
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 eea1fe3c..016ec20d 100644
--- a/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java
+++ b/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java
@@ -30,14 +30,26 @@
 
 package com.google.protobuf;
 
+import java.io.IOException;
+
 /**
  * LazyFieldLite encapsulates the logic of lazily parsing message fields. It stores
- * the message in a ByteString initially and then parse it on-demand.
+ * the message in a ByteString initially and then parses it on-demand.
+ *
+ * LazyFieldLite is thread-compatible: concurrent reads are safe once the proto that this
+ * LazyFieldLite is a part of is no longer being mutated by its Builder. However, explicit
+ * synchronization is needed under read/write situations.
  *
- * LazyField is thread-compatible e.g. concurrent read are safe, however,
- * synchronizations are needed under read/write situations.
+ * When a LazyFieldLite is used in the context of a MessageLite object, its behavior is considered
+ * to be immutable and none of the setter methods in its API are expected to be invoked. All of the
+ * getters are expected to be thread-safe. When used in the context of a MessageLite.Builder,
+ * setters can be invoked, but there is no guarantee of thread safety.
+ * 
+ * TODO(yatin,dweis): Consider splitting this class's functionality and put the mutable methods
+ * into a separate builder class to allow us to give stronger compile-time guarantees.
  *
- * This class is internal implementation detail, so you don't need to use it directly.
+ * This class is internal implementation detail of the protobuf library, so you don't need to use it
+ * directly.
  *
  * @author xiangl@google.com (Xiang Li)
  */
@@ -46,8 +58,34 @@ public class LazyFieldLite {
       ExtensionRegistryLite.getEmptyRegistry();
 
   /**
-   * A delayed-parsed version of the bytes. When this is non-null then {@code extensionRegistry } is
-   * also non-null and {@code value} and {@code memoizedBytes} are null.
+   * The value associated with the LazyFieldLite object is stored in one or more of the following
+   * three fields (delayedBytes, value, memoizedBytes). They should together be interpreted as
+   * follows.
+   * 1) delayedBytes can be non-null, while value and memoizedBytes is null. The object will be in
+   *    this state while the value for the object has not yet been parsed.
+   * 2) Both delayedBytes and value are non-null. The object transitions to this state as soon as
+   *    some caller needs to access the value (by invoking getValue()).
+   * 3) memoizedBytes is merely an optimization for calls to LazyFieldLite.toByteString() to avoid
+   *    recomputing the ByteString representation on each call. Instead, when the value is parsed
+   *    from delayedBytes, we will also assign the contents of delayedBytes to memoizedBytes (since
+   *    that is the ByteString representation of value).
+   * 4) Finally, if the LazyFieldLite was created directly with a parsed MessageLite value, then
+   *    delayedBytes will be null, and memoizedBytes will be initialized only upon the first call to
+   *    LazyFieldLite.toByteString().
+   *
+   * Given the above conditions, any caller that needs a serialized representation of this object
+   * must first check if the memoizedBytes or delayedBytes ByteString is non-null and use it
+   * directly; if both of those are null, it can look at the parsed value field. Similarly, any
+   * caller that needs a parsed value must first check if the value field is already non-null, if
+   * not it must parse the value from delayedBytes.
+   */
+
+  /**
+   * A delayed-parsed version of the contents of this field. When this field is non-null, then the
+   * "value" field is allowed to be null until the time that the value needs to be read.
+   *
+   * When delayedBytes is non-null then {@code extensionRegistry} is required to also be non-null.
+   * {@code value} and {@code memoizedBytes} will be initialized lazily.
    */
   private ByteString delayedBytes;
 
@@ -60,12 +98,15 @@ public class LazyFieldLite {
   private ExtensionRegistryLite extensionRegistry;
 
   /**
-   * The parsed value. When this is non-null then {@code delayedBytes} will be null.
+   * The parsed value. When this is null and a caller needs access to the MessageLite value, then
+   * {@code delayedBytes} will be parsed lazily at that time.
    */
   protected volatile MessageLite value;
 
   /**
-   * The memoized bytes for {@code value}. Will be null when {@code value} is null.
+   * The memoized bytes for {@code value}. This is an optimization for the toByteString() method to
+   * not have to recompute its return-value on each invocation.
+   * TODO(yatin): Figure out whether this optimization is actually necessary.
    */
   private volatile ByteString memoizedBytes;
 
@@ -230,6 +271,46 @@ public class LazyFieldLite {
       return;
     }
   }
+  
+  /**
+   * Merges another instance's contents from a stream.
+   *
+   * <p>LazyField is not thread-safe for write access. Synchronizations are needed
+   * under read/write situations.
+   */
+  public void mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+      throws IOException {
+    if (this.containsDefaultInstance()) {
+      setByteString(input.readBytes(), extensionRegistry);
+      return;
+    }
+
+    // If the other field has an extension registry but this does not, copy over the other extension
+    // registry.
+    if (this.extensionRegistry == null) {
+      this.extensionRegistry = extensionRegistry;
+    }
+
+    // In the case that both of them are not parsed we simply concatenate the bytes to save time. In
+    // the (probably rare) case that they have different extension registries there is a chance that
+    // some of the extensions may be dropped, but the tradeoff of making this operation fast seems
+    // to outway the benefits of combining the extension registries, which is not normally done for
+    // lite protos anyways.
+    if (this.delayedBytes != null) {
+      setByteString(this.delayedBytes.concat(input.readBytes()), this.extensionRegistry);
+      return;
+    }
+
+    // We are parsed and both contain data. We won't drop any extensions here directly, but in the
+    // case that the extension registries are not the same then we might in the future if we
+    // need to serialize and parse a message again.
+    try {
+      setValue(value.toBuilder().mergeFrom(input, extensionRegistry).build());
+    } catch (InvalidProtocolBufferException e) {
+      // Nothing is logged and no exceptions are thrown. Clients will be unaware that a proto
+      // was invalid.
+    }
+  }
 
   private static MessageLite mergeValueAndBytes(
       MessageLite value, ByteString otherBytes, ExtensionRegistryLite extensionRegistry) {
@@ -259,10 +340,10 @@ public class LazyFieldLite {
    * parsed. Be careful when using this method.
    */
   public int getSerializedSize() {
-    if (delayedBytes != null) {
-      return delayedBytes.size();
-    } else if (memoizedBytes != null) {
+    if (memoizedBytes != null) {
       return memoizedBytes.size();
+    } else if (delayedBytes != null) {
+      return delayedBytes.size();
     } else if (value != null) {
       return value.getSerializedSize();
     } else {
@@ -274,12 +355,12 @@ public class LazyFieldLite {
    * Returns a BytesString for this field in a thread-safe way.
    */
   public ByteString toByteString() {
-    if (delayedBytes != null) {
-      return delayedBytes;
-    }
     if (memoizedBytes != null) {
       return memoizedBytes;
     }
+    if (delayedBytes != null) {
+      return delayedBytes;
+    }
     synchronized (this) {
       if (memoizedBytes != null) {
         return memoizedBytes;
@@ -311,18 +392,15 @@ public class LazyFieldLite {
               .parseFrom(delayedBytes, extensionRegistry);
           this.value = parsedValue;
           this.memoizedBytes = delayedBytes;
-          this.delayedBytes = null;
         } else {
           this.value = defaultInstance;
           this.memoizedBytes = ByteString.EMPTY;
-          this.delayedBytes = null;
         }
       } catch (InvalidProtocolBufferException e) {
         // Nothing is logged and no exceptions are thrown. Clients will be unaware that this proto
         // was invalid.
         this.value = defaultInstance;
         this.memoizedBytes = ByteString.EMPTY;
-        this.delayedBytes = null;
       }
     }
   }
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 c3be3cca..68c430cf 100644
--- a/java/core/src/main/java/com/google/protobuf/LazyStringArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/LazyStringArrayList.java
@@ -30,12 +30,12 @@
 
 package com.google.protobuf;
 
-import java.util.Arrays;
-import java.util.List;
 import java.util.AbstractList;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
 import java.util.RandomAccess;
 
 /**
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 e69de29b..2a6e0e30 100644
--- a/java/core/src/main/java/com/google/protobuf/MessageLiteToString.java
+++ b/java/core/src/main/java/com/google/protobuf/MessageLiteToString.java
@@ -0,0 +1,200 @@
+// 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 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;
+
+/**
+ * Helps generate {@link String} representations of {@link MessageLite} protos.
+ */
+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";
+
+  /**
+   * 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
+   * the objcet instance. This acts as an indicator that this should not be relied on for
+   * comparisons.
+   *
+   * <p>For use by generated code only.
+   */
+  static String toString(MessageLite messageLite, String commentString) {
+    StringBuilder buffer = new StringBuilder();
+    buffer.append("# ").append(commentString);
+    reflectivePrintWithIndent(messageLite, buffer, 0);
+    return buffer.toString();
+  }
+
+  /**
+   * Reflectively prints the {@link MessageLite} to the buffer at given {@code indent} level.
+   *
+   * @param buffer the buffer to write to
+   * @param indent the number of spaces to indent the proto by
+   */
+  private static void reflectivePrintWithIndent(
+      MessageLite messageLite, StringBuilder buffer, int indent) {
+    // 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>();
+    for (Method method : messageLite.getClass().getDeclaredMethods()) {
+      if (method.getParameterTypes().length == 0) {
+        nameToNoArgMethod.put(method.getName(), method);
+      }
+    }
+
+    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 "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);
+
+      // 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)) {
+          printField(
+              buffer,
+              indent,
+              upperUnderscore.toLowerCase(),
+              GeneratedMessageLite.invokeOrDie(getMethod, messageLite));
+        }
+        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) {
+      Iterator<Map.Entry<GeneratedMessageLite.ExtensionDescriptor, Object>> iter =
+          ((GeneratedMessageLite.ExtendableMessage<?, ?>) messageLite).extensions.iterator();
+      while (iter.hasNext()) {
+        Map.Entry<GeneratedMessageLite.ExtensionDescriptor, Object> entry = iter.next();
+        printField(buffer, indent, "[" + entry.getKey().getNumber() + "]", entry.getValue());
+      }
+    }
+
+    if (((GeneratedMessageLite) messageLite).unknownFields != null) {
+      ((GeneratedMessageLite) messageLite).unknownFields.printWithIndent(buffer, indent);
+    }
+  }
+
+  /**
+   * Formats a text proto field.
+   *
+   * <p>For use by generated code only.
+   *
+   * @param buffer the buffer to write to
+   * @param indent the number of spaces the proto should be indented by
+   * @param name the field name (in lower underscore case)
+   * @param object the object value of the field
+   */
+  static final void printField(StringBuilder buffer, int indent, String name, Object object) {
+    if (object instanceof List<?>) {
+      List<?> list = (List<?>) object;
+      for (Object entry : list) {
+        printField(buffer, indent, name, entry);
+      }
+      return;
+    }
+
+    buffer.append('\n');
+    for (int i = 0; i < indent; i++) {
+      buffer.append(' ');
+    }
+    buffer.append(name);
+
+    if (object instanceof String) {
+      buffer.append(": \"").append(TextFormatEscaper.escapeText((String) object)).append('"');
+    } else if (object instanceof ByteString) {
+      buffer.append(": \"").append(TextFormatEscaper.escapeBytes((ByteString) object)).append('"');
+    } else if (object instanceof GeneratedMessageLite) {
+      buffer.append(" {");
+      reflectivePrintWithIndent((GeneratedMessageLite) object, buffer, indent + 2);
+      buffer.append("\n");
+      for (int i = 0; i < indent; i++) {
+        buffer.append(' ');
+      }
+      buffer.append("}");
+    } else {
+      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);
+      }
+    }
+    return upperCamelCaseName;
+  }
+}
diff --git a/java/core/src/main/java/com/google/protobuf/NioByteString.java b/java/core/src/main/java/com/google/protobuf/NioByteString.java
index f71e41b2..6163c7b1 100644
--- a/java/core/src/main/java/com/google/protobuf/NioByteString.java
+++ b/java/core/src/main/java/com/google/protobuf/NioByteString.java
@@ -30,15 +30,14 @@
 
 package com.google.protobuf;
 
-import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InvalidObjectException;
 import java.io.ObjectInputStream;
 import java.io.OutputStream;
 import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
 import java.nio.InvalidMarkException;
-import java.nio.channels.Channels;
 import java.nio.charset.Charset;
 import java.util.Collections;
 import java.util.List;
@@ -54,7 +53,7 @@ final class NioByteString extends ByteString.LeafByteString {
       throw new NullPointerException("buffer");
     }
 
-    this.buffer = buffer.slice();
+    this.buffer = buffer.slice().order(ByteOrder.nativeOrder());
   }
 
   // =================================================================
@@ -119,7 +118,7 @@ final class NioByteString extends ByteString.LeafByteString {
 
   @Override
   public void writeTo(OutputStream out) throws IOException {
-    writeToInternal(out, buffer.position(), buffer.remaining());
+    out.write(toByteArray());
   }
 
   @Override
@@ -137,14 +136,12 @@ final class NioByteString extends ByteString.LeafByteString {
       return;
     }
 
-    // Slow path
-    if (out instanceof FileOutputStream || numberToWrite >= 8192) {
-      // Use a channel to write out the ByteBuffer.
-      Channels.newChannel(out).write(slice(sourceOffset, sourceOffset + numberToWrite));
-    } else {
-      // Just copy the data to an array and write it.
-      out.write(toByteArray());
-    }
+    ByteBufferWriter.write(slice(sourceOffset, sourceOffset + numberToWrite), out);
+  }
+
+  @Override
+  void writeTo(ByteOutput output) throws IOException {
+    output.writeLazy(buffer.slice());
   }
 
   @Override
@@ -159,46 +156,30 @@ final class NioByteString extends ByteString.LeafByteString {
 
   @Override
   protected String toStringInternal(Charset charset) {
-    byte[] bytes;
-    int offset;
+    final byte[] bytes;
+    final int offset;
+    final int length;
     if (buffer.hasArray()) {
       bytes = buffer.array();
       offset = buffer.arrayOffset() + buffer.position();
+      length = buffer.remaining();
     } else {
+      // TODO(nathanmittler): Can we optimize this?
       bytes = toByteArray();
       offset = 0;
+      length = bytes.length;
     }
-    return new String(bytes, offset, size(), charset);
+    return new String(bytes, offset, length, charset);
   }
 
   @Override
   public boolean isValidUtf8() {
-    // TODO(nathanmittler): add a ByteBuffer fork for Utf8.isValidUtf8 to avoid the copy
-    byte[] bytes;
-    int startIndex;
-    if (buffer.hasArray()) {
-      bytes = buffer.array();
-      startIndex = buffer.arrayOffset() + buffer.position();
-    } else {
-      bytes = toByteArray();
-      startIndex = 0;
-    }
-    return Utf8.isValidUtf8(bytes, startIndex, startIndex + size());
+    return Utf8.isValidUtf8(buffer);
   }
 
   @Override
   protected int partialIsValidUtf8(int state, int offset, int length) {
-    // TODO(nathanmittler): TODO add a ByteBuffer fork for Utf8.partialIsValidUtf8 to avoid the copy
-    byte[] bytes;
-    int startIndex;
-    if (buffer.hasArray()) {
-      bytes = buffer.array();
-      startIndex = buffer.arrayOffset() + buffer.position();
-    } else {
-      bytes = toByteArray();
-      startIndex = 0;
-    }
-    return Utf8.partialIsValidUtf8(state, bytes, startIndex, startIndex + size());
+    return Utf8.partialIsValidUtf8(state, buffer, offset, offset + length);
   }
 
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/Parser.java b/java/core/src/main/java/com/google/protobuf/Parser.java
index 3fa11c3b..6db69247 100644
--- a/java/core/src/main/java/com/google/protobuf/Parser.java
+++ b/java/core/src/main/java/com/google/protobuf/Parser.java
@@ -30,7 +30,6 @@
 
 package com.google.protobuf;
 
-import java.io.IOException;
 import java.io.InputStream;
 
 /**
diff --git a/java/core/src/main/java/com/google/protobuf/RopeByteString.java b/java/core/src/main/java/com/google/protobuf/RopeByteString.java
index 8badfabd..3f3e9bd1 100644
--- a/java/core/src/main/java/com/google/protobuf/RopeByteString.java
+++ b/java/core/src/main/java/com/google/protobuf/RopeByteString.java
@@ -48,10 +48,11 @@ import java.util.Stack;
 /**
  * Class to represent {@code ByteStrings} formed by concatenation of other
  * ByteStrings, without copying the data in the pieces. The concatenation is
- * represented as a tree whose leaf nodes are each a {@link LiteralByteString}.
+ * represented as a tree whose leaf nodes are each a
+ * {@link com.google.protobuf.ByteString.LeafByteString}.
  *
  * <p>Most of the operation here is inspired by the now-famous paper <a
- * href="http://www.cs.ubc.ca/local/reading/proceedings/spe91-95/spe/vol25/issue12/spe986.pdf">
+ * href="https://web.archive.org/web/20060202015456/http://www.cs.ubc.ca/local/reading/proceedings/spe91-95/spe/vol25/issue12/spe986.pdf">
  * BAP95 </a> Ropes: an Alternative to Strings hans-j. boehm, russ atkinson and
  * michael plass
  *
@@ -139,8 +140,9 @@ final class RopeByteString extends ByteString {
   /**
    * Concatenate the given strings while performing various optimizations to
    * slow the growth rate of tree depth and tree node count. The result is
-   * either a {@link LiteralByteString} or a {@link RopeByteString}
-   * depending on which optimizations, if any, were applied.
+   * either a {@link com.google.protobuf.ByteString.LeafByteString} or a
+   * {@link RopeByteString} depending on which optimizations, if any, were
+   * applied.
    *
    * <p>Small pieces of length less than {@link
    * ByteString#CONCATENATE_BY_COPY_SIZE} may be copied by value here, as in
@@ -294,8 +296,7 @@ final class RopeByteString extends ByteString {
    *
    * <p>Substrings of {@code length < 2} should result in at most a single
    * recursive call chain, terminating at a leaf node. Thus the result will be a
-   * {@link LiteralByteString}. {@link #RopeByteString(ByteString,
-   * ByteString)}.
+   * {@link com.google.protobuf.ByteString.LeafByteString}.
    *
    * @param beginIndex start at this index
    * @param endIndex   the last character is the one before this index
@@ -368,7 +369,7 @@ final class RopeByteString extends ByteString {
 
   @Override
   public List<ByteBuffer> asReadOnlyByteBufferList() {
-    // Walk through the list of LiteralByteString's that make up this
+    // Walk through the list of LeafByteString's that make up this
     // rope, and add each one as a read-only ByteBuffer.
     List<ByteBuffer> result = new ArrayList<ByteBuffer>();
     PieceIterator pieces = new PieceIterator(this);
@@ -400,6 +401,12 @@ final class RopeByteString extends ByteString {
   }
 
   @Override
+  void writeTo(ByteOutput output) throws IOException {
+    left.writeTo(output);
+    right.writeTo(output);
+  }
+
+  @Override
   protected String toStringInternal(Charset charset) {
     return new String(toByteArray(), charset);
   }
@@ -709,9 +716,10 @@ final class RopeByteString extends ByteString {
     }
 
     /**
-     * Returns the next item and advances one {@code LiteralByteString}.
+     * Returns the next item and advances one
+     * {@link com.google.protobuf.ByteString.LeafByteString}.
      *
-     * @return next non-empty LiteralByteString or {@code null}
+     * @return next non-empty LeafByteString or {@code null}
      */
     @Override
     public LeafByteString next() {
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 0674d2e2..dff19328 100644
--- a/java/core/src/main/java/com/google/protobuf/SmallSortedMap.java
+++ b/java/core/src/main/java/com/google/protobuf/SmallSortedMap.java
@@ -35,12 +35,12 @@ import java.util.AbstractSet;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
-import java.util.TreeMap;
 import java.util.List;
 import java.util.Map;
 import java.util.NoSuchElementException;
 import java.util.Set;
 import java.util.SortedMap;
+import java.util.TreeMap;
 
 /**
  * A custom map implementation from FieldDescriptor to Object optimized to
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 c99b5285..edf114fa 100644
--- a/java/core/src/main/java/com/google/protobuf/TextFormat.java
+++ b/java/core/src/main/java/com/google/protobuf/TextFormat.java
@@ -425,7 +425,7 @@ public final class TextFormat {
         case STRING:
           generator.print("\"");
           generator.print(escapeNonAscii
-              ? escapeText((String) value)
+              ? TextFormatEscaper.escapeText((String) value)
               : escapeDoubleQuotesAndBackslashes((String) value)
                   .replace("\n", "\\n"));
           generator.print("\"");
@@ -661,6 +661,14 @@ public final class TextFormat {
       nextToken();
     }
 
+    int getLine() {
+      return line;
+    }
+
+    int getColumn() {
+      return column;
+    }
+
     /** Are we at the end of the input? */
     public boolean atEnd() {
       return currentToken.length() == 0;
@@ -1074,7 +1082,7 @@ public final class TextFormat {
     private ParseException floatParseException(final NumberFormatException e) {
       return parseException("Couldn't parse number: " + e.getMessage());
     }
-    
+
     /**
      * Returns a {@link UnknownFieldParseException} with the line and column
      * numbers of the previous token in the description, and the unknown field
@@ -1133,7 +1141,7 @@ public final class TextFormat {
       return column;
     }
   }
-  
+
   /**
    * Thrown when encountering an unknown field while parsing
    * a text format message.
@@ -1257,11 +1265,14 @@ public final class TextFormat {
 
     private final boolean allowUnknownFields;
     private final SingularOverwritePolicy singularOverwritePolicy;
+    private TextFormatParseInfoTree.Builder parseInfoTreeBuilder;
 
-    private Parser(boolean allowUnknownFields,
-        SingularOverwritePolicy singularOverwritePolicy) {
+    private Parser(
+        boolean allowUnknownFields, SingularOverwritePolicy singularOverwritePolicy,
+        TextFormatParseInfoTree.Builder parseInfoTreeBuilder) {
       this.allowUnknownFields = allowUnknownFields;
       this.singularOverwritePolicy = singularOverwritePolicy;
+      this.parseInfoTreeBuilder = parseInfoTreeBuilder;
     }
 
     /**
@@ -1278,6 +1289,7 @@ public final class TextFormat {
       private boolean allowUnknownFields = false;
       private SingularOverwritePolicy singularOverwritePolicy =
           SingularOverwritePolicy.ALLOW_SINGULAR_OVERWRITES;
+      private TextFormatParseInfoTree.Builder parseInfoTreeBuilder = null;
 
 
       /**
@@ -1288,8 +1300,15 @@ public final class TextFormat {
         return this;
       }
 
+      public Builder setParseInfoTreeBuilder(
+          TextFormatParseInfoTree.Builder parseInfoTreeBuilder) {
+        this.parseInfoTreeBuilder = parseInfoTreeBuilder;
+        return this;
+      }
+
       public Parser build() {
-        return new Parser(allowUnknownFields, singularOverwritePolicy);
+        return new Parser(
+            allowUnknownFields, singularOverwritePolicy, parseInfoTreeBuilder);
       }
     }
 
@@ -1380,7 +1399,21 @@ public final class TextFormat {
                             final ExtensionRegistry extensionRegistry,
                             final MessageReflection.MergeTarget target)
                             throws ParseException {
+      mergeField(tokenizer, extensionRegistry, target, parseInfoTreeBuilder);
+    }
+
+    /**
+     * Parse a single field from {@code tokenizer} and merge it into
+     * {@code builder}.
+     */
+    private void mergeField(final Tokenizer tokenizer,
+                            final ExtensionRegistry extensionRegistry,
+                            final MessageReflection.MergeTarget target,
+                            TextFormatParseInfoTree.Builder parseTreeBuilder)
+                            throws ParseException {
       FieldDescriptor field = null;
+      int startLine = tokenizer.getLine();
+      int startColumn = tokenizer.getColumn();
       final Descriptor type = target.getDescriptorForType();
       ExtensionRegistry.ExtensionInfo extension = null;
 
@@ -1472,14 +1505,51 @@ public final class TextFormat {
       // Handle potential ':'.
       if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
         tokenizer.tryConsume(":");  // optional
+        if (parseTreeBuilder != null) {
+          TextFormatParseInfoTree.Builder childParseTreeBuilder =
+              parseTreeBuilder.getBuilderForSubMessageField(field);
+          consumeFieldValues(tokenizer, extensionRegistry, target, field, extension,
+              childParseTreeBuilder);
+        } else {
+          consumeFieldValues(tokenizer, extensionRegistry, target, field, extension,
+              parseTreeBuilder);
+        }
       } else {
         tokenizer.consume(":");  // required
+        consumeFieldValues(
+            tokenizer, extensionRegistry, target, field, extension, parseTreeBuilder);
       }
+
+      if (parseTreeBuilder != null) {
+        parseTreeBuilder.setLocation(
+            field, TextFormatParseLocation.create(startLine, startColumn));
+      }
+
+      // For historical reasons, fields may optionally be separated by commas or
+      // semicolons.
+      if (!tokenizer.tryConsume(";")) {
+        tokenizer.tryConsume(",");
+      }
+    }
+
+    /**
+     * Parse a one or more field values from {@code tokenizer} and merge it into
+     * {@code builder}.
+     */
+    private void consumeFieldValues(
+        final Tokenizer tokenizer,
+        final ExtensionRegistry extensionRegistry,
+        final MessageReflection.MergeTarget target,
+        final FieldDescriptor field,
+        final ExtensionRegistry.ExtensionInfo extension,
+        final TextFormatParseInfoTree.Builder parseTreeBuilder)
+        throws ParseException {
       // Support specifying repeated field values as a comma-separated list.
       // Ex."foo: [1, 2, 3]"
       if (field.isRepeated() && tokenizer.tryConsume("[")) {
         while (true) {
-          consumeFieldValue(tokenizer, extensionRegistry, target, field, extension);
+          consumeFieldValue(tokenizer, extensionRegistry, target, field, extension,
+              parseTreeBuilder);
           if (tokenizer.tryConsume("]")) {
             // End of list.
             break;
@@ -1487,13 +1557,8 @@ public final class TextFormat {
           tokenizer.consume(",");
         }
       } else {
-        consumeFieldValue(tokenizer, extensionRegistry, target, field, extension);
-      }
-
-      // For historical reasons, fields may optionally be separated by commas or
-      // semicolons.
-      if (!tokenizer.tryConsume(";")) {
-        tokenizer.tryConsume(",");
+        consumeFieldValue(
+            tokenizer, extensionRegistry, target, field, extension, parseTreeBuilder);
       }
     }
 
@@ -1506,7 +1571,8 @@ public final class TextFormat {
         final ExtensionRegistry extensionRegistry,
         final MessageReflection.MergeTarget target,
         final FieldDescriptor field,
-        final ExtensionRegistry.ExtensionInfo extension)
+        final ExtensionRegistry.ExtensionInfo extension,
+        final TextFormatParseInfoTree.Builder parseTreeBuilder)
         throws ParseException {
       Object value = null;
 
@@ -1528,7 +1594,7 @@ public final class TextFormat {
             throw tokenizer.parseException(
               "Expected \"" + endToken + "\".");
           }
-          mergeField(tokenizer, extensionRegistry, subField);
+          mergeField(tokenizer, extensionRegistry, subField, parseTreeBuilder);
         }
 
         value = subField.finish();
@@ -1704,52 +1770,6 @@ public final class TextFormat {
   // Some of these methods are package-private because Descriptors.java uses
   // them.
 
-  private interface ByteSequence {
-    int size();
-    byte byteAt(int offset);
-  }
-
-  /**
-   * Escapes bytes in the format used in protocol buffer text format, which
-   * is the same as the format used for C string literals.  All bytes
-   * that are not printable 7-bit ASCII characters are escaped, as well as
-   * backslash, single-quote, and double-quote characters.  Characters for
-   * which no defined short-hand escape sequence is defined will be escaped
-   * using 3-digit octal sequences.
-   */
-  public static String escapeBytes(final ByteSequence input) {
-    final StringBuilder builder = new StringBuilder(input.size());
-    for (int i = 0; i < input.size(); i++) {
-      final byte b = input.byteAt(i);
-      switch (b) {
-        // Java does not recognize \a or \v, apparently.
-        case 0x07: builder.append("\\a"); break;
-        case '\b': builder.append("\\b"); break;
-        case '\f': builder.append("\\f"); break;
-        case '\n': builder.append("\\n"); break;
-        case '\r': builder.append("\\r"); break;
-        case '\t': builder.append("\\t"); break;
-        case 0x0b: builder.append("\\v"); break;
-        case '\\': builder.append("\\\\"); break;
-        case '\'': builder.append("\\\'"); break;
-        case '"' : builder.append("\\\""); break;
-        default:
-          // Only ASCII characters between 0x20 (space) and 0x7e (tilde) are
-          // printable.  Other byte values must be escaped.
-          if (b >= 0x20 && b <= 0x7e) {
-            builder.append((char) b);
-          } else {
-            builder.append('\\');
-            builder.append((char) ('0' + ((b >>> 6) & 3)));
-            builder.append((char) ('0' + ((b >>> 3) & 7)));
-            builder.append((char) ('0' + (b & 7)));
-          }
-          break;
-      }
-    }
-    return builder.toString();
-  }
-
   /**
    * Escapes bytes in the format used in protocol buffer text format, which
    * is the same as the format used for C string literals.  All bytes
@@ -1758,33 +1778,15 @@ public final class TextFormat {
    * which no defined short-hand escape sequence is defined will be escaped
    * using 3-digit octal sequences.
    */
-  public static String escapeBytes(final ByteString input) {
-    return escapeBytes(new ByteSequence() {
-      @Override
-      public int size() {
-        return input.size();
-      }
-      @Override
-      public byte byteAt(int offset) {
-        return input.byteAt(offset);
-      }
-    });
+  public static String escapeBytes(ByteString input) {
+    return TextFormatEscaper.escapeBytes(input);
   }
 
   /**
    * Like {@link #escapeBytes(ByteString)}, but used for byte array.
    */
-  public static String escapeBytes(final byte[] input) {
-    return escapeBytes(new ByteSequence() {
-      @Override
-      public int size() {
-        return input.length;
-      }
-      @Override
-      public byte byteAt(int offset) {
-        return input[offset];
-      }
-    });
+  public static String escapeBytes(byte[] input) {
+    return TextFormatEscaper.escapeBytes(input);
   }
 
   /**
@@ -1868,7 +1870,9 @@ public final class TextFormat {
       }
     }
 
-    return ByteString.copyFrom(result, 0, pos);
+    return result.length == pos
+        ? ByteString.wrap(result)  // This reference has not been out of our control.
+        : ByteString.copyFrom(result, 0, pos);
   }
 
   /**
@@ -1896,7 +1900,7 @@ public final class TextFormat {
    * Escape double quotes and backslashes in a String for unicode output of a message.
    */
   public static String escapeDoubleQuotesAndBackslashes(final String input) {
-    return input.replace("\\", "\\\\").replace("\"", "\\\"");
+    return TextFormatEscaper.escapeDoubleQuotesAndBackslashes(input);
   }
 
   /**
diff --git a/java/core/src/main/java/com/google/protobuf/TextFormatEscaper.java b/java/core/src/main/java/com/google/protobuf/TextFormatEscaper.java
index e69de29b..da9ceadd 100644
--- a/java/core/src/main/java/com/google/protobuf/TextFormatEscaper.java
+++ b/java/core/src/main/java/com/google/protobuf/TextFormatEscaper.java
@@ -0,0 +1,137 @@
+// 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;
+
+/**
+ * Provide text format escaping support for proto2 instances.
+ */
+final class TextFormatEscaper {
+  private TextFormatEscaper() {}
+
+  private interface ByteSequence {
+    int size();
+    byte byteAt(int offset);
+  }
+
+  /**
+   * Escapes bytes in the format used in protocol buffer text format, which
+   * is the same as the format used for C string literals.  All bytes
+   * that are not printable 7-bit ASCII characters are escaped, as well as
+   * backslash, single-quote, and double-quote characters.  Characters for
+   * which no defined short-hand escape sequence is defined will be escaped
+   * using 3-digit octal sequences.
+   */
+  static String escapeBytes(final ByteSequence input) {
+    final StringBuilder builder = new StringBuilder(input.size());
+    for (int i = 0; i < input.size(); i++) {
+      final byte b = input.byteAt(i);
+      switch (b) {
+        // Java does not recognize \a or \v, apparently.
+        case 0x07: builder.append("\\a"); break;
+        case '\b': builder.append("\\b"); break;
+        case '\f': builder.append("\\f"); break;
+        case '\n': builder.append("\\n"); break;
+        case '\r': builder.append("\\r"); break;
+        case '\t': builder.append("\\t"); break;
+        case 0x0b: builder.append("\\v"); break;
+        case '\\': builder.append("\\\\"); break;
+        case '\'': builder.append("\\\'"); break;
+        case '"' : builder.append("\\\""); break;
+        default:
+          // Only ASCII characters between 0x20 (space) and 0x7e (tilde) are
+          // printable.  Other byte values must be escaped.
+          if (b >= 0x20 && b <= 0x7e) {
+            builder.append((char) b);
+          } else {
+            builder.append('\\');
+            builder.append((char) ('0' + ((b >>> 6) & 3)));
+            builder.append((char) ('0' + ((b >>> 3) & 7)));
+            builder.append((char) ('0' + (b & 7)));
+          }
+          break;
+      }
+    }
+    return builder.toString();
+  }
+
+  /**
+   * Escapes bytes in the format used in protocol buffer text format, which
+   * is the same as the format used for C string literals.  All bytes
+   * that are not printable 7-bit ASCII characters are escaped, as well as
+   * backslash, single-quote, and double-quote characters.  Characters for
+   * which no defined short-hand escape sequence is defined will be escaped
+   * using 3-digit octal sequences.
+   */
+  static String escapeBytes(final ByteString input) {
+    return escapeBytes(new ByteSequence() {
+      @Override
+      public int size() {
+        return input.size();
+      }
+      @Override
+      public byte byteAt(int offset) {
+        return input.byteAt(offset);
+      }
+    });
+  }
+
+  /**
+   * Like {@link #escapeBytes(ByteString)}, but used for byte array.
+   */
+  static String escapeBytes(final byte[] input) {
+    return escapeBytes(new ByteSequence() {
+      @Override
+      public int size() {
+        return input.length;
+      }
+      @Override
+      public byte byteAt(int offset) {
+        return input[offset];
+      }
+    });
+  }
+
+  /**
+   * Like {@link #escapeBytes(ByteString)}, but escapes a text string.
+   * Non-ASCII characters are first encoded as UTF-8, then each byte is escaped
+   * individually as a 3-digit octal escape.  Yes, it's weird.
+   */
+  static String escapeText(final String input) {
+    return escapeBytes(ByteString.copyFromUtf8(input));
+  }
+
+  /**
+   * Escape double quotes and backslashes in a String for unicode output of a message.
+   */
+  static String escapeDoubleQuotesAndBackslashes(final String input) {
+    return input.replace("\\", "\\\\").replace("\"", "\\\"");
+  }
+}
diff --git a/java/core/src/main/java/com/google/protobuf/TextFormatParseInfoTree.java b/java/core/src/main/java/com/google/protobuf/TextFormatParseInfoTree.java
new file mode 100644
index 00000000..2ecf912e
--- /dev/null
+++ b/java/core/src/main/java/com/google/protobuf/TextFormatParseInfoTree.java
@@ -0,0 +1,225 @@
+// 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 com.google.protobuf.Descriptors.FieldDescriptor;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+
+
+/**
+ * Data structure which is populated with the locations of each field value parsed from the text.
+ *
+ * <p>The locations of primary fields values are retrieved by {@code getLocation} or
+ * {@code getLocations}.  The locations of sub message values are within nested
+ * {@code TextFormatParseInfoTree}s and are retrieve by {@getNestedTree} or {code @getNestedTrees}.
+ *
+ * <p>The {@code TextFormatParseInfoTree} is created by a Builder.
+ */
+public class TextFormatParseInfoTree {
+
+  // Defines a mapping between each field's descriptor to the list of locations where
+  // its value(s) were was encountered.
+  private Map<FieldDescriptor, List<TextFormatParseLocation>> locationsFromField;
+
+  // Defines a mapping between a field's descriptor to a list of TextFormatParseInfoTrees for
+  // sub message location information.
+  Map<FieldDescriptor, List<TextFormatParseInfoTree>> subtreesFromField;
+
+  /**
+   * Construct a {@code TextFormatParseInfoTree}.
+   *
+   * @param locationsFromField a map of fields to location in the source code
+   * @param subtreeBuildersFromField a map of fields to parse tree location information builders
+   */
+  private TextFormatParseInfoTree(
+      Map<FieldDescriptor, List<TextFormatParseLocation>> locationsFromField,
+      Map<FieldDescriptor, List<TextFormatParseInfoTree.Builder>> subtreeBuildersFromField) {
+
+    // The maps are unmodifiable.  The values in the maps are unmodifiable.
+    Map<FieldDescriptor, List<TextFormatParseLocation>> locs =
+        new HashMap<FieldDescriptor, List<TextFormatParseLocation>>();
+    for (Entry<FieldDescriptor, List<TextFormatParseLocation>> kv : locationsFromField.entrySet()) {
+      locs.put(kv.getKey(), Collections.unmodifiableList(kv.getValue()));
+    }
+    this.locationsFromField = Collections.unmodifiableMap(locs);
+
+    Map<FieldDescriptor, List<TextFormatParseInfoTree>> subs =
+        new HashMap<FieldDescriptor, List<TextFormatParseInfoTree>>();
+    for (Entry<FieldDescriptor, List<Builder>> kv : subtreeBuildersFromField.entrySet()) {
+      List<TextFormatParseInfoTree> submessagesOfField = new ArrayList<TextFormatParseInfoTree>();
+      for (Builder subBuilder : kv.getValue()) {
+        submessagesOfField.add(subBuilder.build());
+      }
+      subs.put(kv.getKey(), Collections.unmodifiableList(submessagesOfField));
+    }
+    this.subtreesFromField = Collections.unmodifiableMap(subs);
+  }
+
+ /**
+  * Retrieve all the locations of a field.
+  *
+  * @param fieldDescriptor the the @{link FieldDescriptor} of the desired field
+  * @return a list of the locations of values of the field.  If there are not values
+  *         or the field doesn't exist, an empty list is returned.
+  */
+  public List<TextFormatParseLocation> getLocations(final FieldDescriptor fieldDescriptor) {
+    List<TextFormatParseLocation> result = locationsFromField.get(fieldDescriptor);
+    return (result == null) ? Collections.<TextFormatParseLocation>emptyList() : result;
+  }
+
+  /**
+   * Get the location in the source of a field's value.
+   *
+   * <p>Returns the {@link TextFormatParseLocation} for index-th value of the field in the parsed
+   * text.
+   *
+   * @param fieldDescriptor the @{link FieldDescriptor} of the desired field
+   * @param index the index of the value.
+   * @return the {@link TextFormatParseLocation} of the value
+   * @throws IllegalArgumentException index is out of range
+   */
+  public TextFormatParseLocation getLocation(final FieldDescriptor fieldDescriptor, int index) {
+    return getFromList(getLocations(fieldDescriptor), index, fieldDescriptor);
+  }
+
+  /**
+   * Retrieve a list of all the location information trees for a sub message field.
+   *
+   * @param fieldDescriptor the @{link FieldDescriptor} of the desired field
+   * @return A list of {@link TextFormatParseInfoTree}
+   */
+  public List<TextFormatParseInfoTree> getNestedTrees(final FieldDescriptor fieldDescriptor) {
+    List<TextFormatParseInfoTree> result = subtreesFromField.get(fieldDescriptor);
+    return result == null ? Collections.<TextFormatParseInfoTree>emptyList() : result;
+  }
+
+  /**
+   * Returns the parse info tree for the given field, which must be a message type.
+   *
+   * @param fieldDescriptor the @{link FieldDescriptor} of the desired sub message
+   * @param index the index of message value.
+   * @return the {@code ParseInfoTree} of the message value. {@code null} is returned if the field
+   *         doesn't exist or the index is out of range.
+   * @throws IllegalArgumentException if index is out of range
+   */
+  public TextFormatParseInfoTree getNestedTree(final FieldDescriptor fieldDescriptor, int index) {
+    return getFromList(getNestedTrees(fieldDescriptor), index, fieldDescriptor);
+  }
+
+  /**
+   * Create a builder for a {@code ParseInfoTree}.
+   *
+   * @return the builder
+   */
+  public static Builder builder() {
+    return new Builder();
+  }
+
+  private static <T> T getFromList(List<T> list, int index, FieldDescriptor fieldDescriptor) {
+    if (index >= list.size() || index < 0)  {
+      throw new IllegalArgumentException(String.format("Illegal index field: %s, index %d",
+          fieldDescriptor == null ? "<null>" : fieldDescriptor.getName(), index));
+    }
+    return list.get(index);
+  }
+
+  /**
+   * Builder for a {@link TextFormatParseInfoTree}.
+   */
+  public static class Builder {
+
+    private Map<FieldDescriptor, List<TextFormatParseLocation>> locationsFromField;
+
+    // Defines a mapping between a field's descriptor to a list of ParseInfoTrees builders for
+    // sub message location information.
+    private Map<FieldDescriptor, List<Builder>> subtreeBuildersFromField;
+
+     /**
+     * Create a root level {@ParseInfoTree} builder.
+     */
+    private Builder() {
+      locationsFromField = new HashMap<FieldDescriptor, List<TextFormatParseLocation>>();
+      subtreeBuildersFromField = new HashMap<FieldDescriptor, List<Builder>>();
+    }
+
+    /**
+     * Record the starting location of a single value for a field.
+     *
+     * @param fieldDescriptor the field
+     * @param location source code location information
+     */
+    public Builder setLocation(
+        final FieldDescriptor fieldDescriptor, TextFormatParseLocation location) {
+      List<TextFormatParseLocation> fieldLocations = locationsFromField.get(fieldDescriptor);
+      if (fieldLocations == null) {
+        fieldLocations = new ArrayList<TextFormatParseLocation>();
+        locationsFromField.put(fieldDescriptor, fieldLocations);
+      }
+      fieldLocations.add(location);
+      return this;
+    }
+
+    /**
+     * Set for a sub message.
+     *
+     * <p>A new builder is created for a sub message. The builder that is returned is a new builder.
+     * The return is <emph>not</emph> the invoked {@code builder.getBuilderForSubMessageField}.
+     *
+     * @param fieldDescriptor the field whose value is the submessage
+     * @return a new Builder for the sub message
+     */
+    public Builder getBuilderForSubMessageField(final FieldDescriptor fieldDescriptor) {
+      List<Builder> submessageBuilders = subtreeBuildersFromField.get(fieldDescriptor);
+      if (submessageBuilders == null) {
+        submessageBuilders = new ArrayList<Builder>();
+        subtreeBuildersFromField.put(fieldDescriptor, submessageBuilders);
+      }
+      Builder subtreeBuilder = new Builder();
+      submessageBuilders.add(subtreeBuilder);
+      return subtreeBuilder;
+    }
+
+    /**
+     * Build the {@code TextFormatParseInfoTree}.
+     *
+     * @return the {@code TextFormatParseInfoTree}
+     */
+    public TextFormatParseInfoTree build() {
+      return new TextFormatParseInfoTree(locationsFromField, subtreeBuildersFromField);
+    }
+  }
+}
diff --git a/java/core/src/main/java/com/google/protobuf/TextFormatParseLocation.java b/java/core/src/main/java/com/google/protobuf/TextFormatParseLocation.java
new file mode 100644
index 00000000..cce286e1
--- /dev/null
+++ b/java/core/src/main/java/com/google/protobuf/TextFormatParseLocation.java
@@ -0,0 +1,104 @@
+// 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 java.util.Arrays;
+
+/**
+ * A location in the source code.
+ *
+ * <p>A location is the starting line number and starting column number.
+ */
+public final class TextFormatParseLocation {
+
+  /**
+   * The empty location.
+   */
+  public static final TextFormatParseLocation EMPTY = new TextFormatParseLocation(-1, -1);
+
+  /**
+   * Create a location.
+   *
+   * @param line the starting line number
+   * @param column the starting column number
+   * @return a {@code ParseLocation}
+   */
+  static TextFormatParseLocation create(int line, int column) {
+    if (line == -1 && column == -1) {
+      return EMPTY;
+    }
+    if (line < 0 || column < 0) {
+      throw new IllegalArgumentException(
+          String.format("line and column values must be >= 0: line %d, column: %d", line, column));
+    }
+    return new TextFormatParseLocation(line, column);
+  }
+
+  private final int line;
+  private final int column;
+
+  private TextFormatParseLocation(int line, int column) {
+    this.line = line;
+    this.column = column;
+  }
+
+  public int getLine() {
+    return line;
+  }
+
+  public int getColumn() {
+    return column;
+  }
+
+  @Override
+  public String toString() {
+    return String.format("ParseLocation{line=%d, column=%d}", line, column);
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof TextFormatParseLocation)) {
+      return false;
+    }
+    TextFormatParseLocation that = (TextFormatParseLocation) o;
+    return (this.line == that.getLine())
+         && (this.column == that.getColumn());
+  }
+
+  @Override
+  public int hashCode() {
+    int[] values = {line, column};
+    return Arrays.hashCode(values);
+  }
+}
diff --git a/java/core/src/main/java/com/google/protobuf/UnknownFieldSetLite.java b/java/core/src/main/java/com/google/protobuf/UnknownFieldSetLite.java
index 435ad4d4..9500f905 100644
--- a/java/core/src/main/java/com/google/protobuf/UnknownFieldSetLite.java
+++ b/java/core/src/main/java/com/google/protobuf/UnknownFieldSetLite.java
@@ -61,15 +61,6 @@ public final class UnknownFieldSetLite {
   public static UnknownFieldSetLite getDefaultInstance() {
     return DEFAULT_INSTANCE;
   }
-
-  /**
-   * Returns an empty {@code UnknownFieldSetLite.Builder}.
-   *
-   * <p>For use by generated code only.
-   */
-  public static Builder newBuilder() {
-    return new Builder();
-  }
   
   /**
    * Returns a new mutable instance.
@@ -262,6 +253,21 @@ public final class UnknownFieldSetLite {
     return hashCode;
   }
 
+  /**
+   * Prints a String representation of the unknown field set.
+   *
+   * <p>For use by generated code only.
+   *
+   * @param buffer the buffer to write to
+   * @param indent the number of spaces the fields should be indented by
+   */
+  final void printWithIndent(StringBuilder buffer, int indent) {
+    for (int i = 0; i < count; i++) {
+      int fieldNumber = WireFormat.getTagFieldNumber(tags[i]);
+      MessageLiteToString.printField(buffer, indent, String.valueOf(fieldNumber), objects[i]);
+    }
+  }
+
   private void storeField(int tag, Object value) {
     ensureCapacity();
     
@@ -369,90 +375,4 @@ public final class UnknownFieldSetLite {
     }
     return this;
   }
-  
-  /**
-   * Builder for {@link UnknownFieldSetLite}s.
-   *
-   * <p>Use {@link UnknownFieldSet#newBuilder()} to construct a {@code Builder}.
-   *
-   * <p>For use by generated code only.
-   */
-  // TODO(dweis): Update the mutable API to no longer need this builder and delete.
-  public static final class Builder {
-
-    private UnknownFieldSetLite set;
-    
-    private Builder() {
-      this.set = null;
-    }
-
-    /**
-     * Ensures internal state is initialized for use.
-     */
-    private void ensureNotBuilt() {
-      if (set == null) {
-        set = new UnknownFieldSetLite();
-      }
-      
-      set.checkMutable();
-    }
-    
-    /**
-     * Parse a single field from {@code input} and merge it into this set.
-     *
-     * <p>For use by generated code only.
-     *
-     * @param tag The field's tag number, which was already parsed.
-     * @return {@code false} if the tag is an end group tag.
-     */
-    boolean mergeFieldFrom(final int tag, final CodedInputStream input) throws IOException {
-      ensureNotBuilt();
-      return set.mergeFieldFrom(tag, input);
-    }
-
-    /**
-     * Convenience method for merging a new field containing a single varint
-     * value. This is used in particular when an unknown enum value is
-     * encountered.
-     *
-     * <p>For use by generated code only.
-     */
-    Builder mergeVarintField(int fieldNumber, int value) {
-      ensureNotBuilt();
-      set.mergeVarintField(fieldNumber, value);
-      return this;
-    }
-    
-    /**
-     * Convenience method for merging a length-delimited field.
-     *
-     * <p>For use by generated code only.
-     */
-    public Builder mergeLengthDelimitedField(final int fieldNumber, final ByteString value) {
-      ensureNotBuilt();  
-      set.mergeLengthDelimitedField(fieldNumber, value);
-      return this;
-    }
-    
-    /**
-     * Build the {@link UnknownFieldSetLite} and return it.
-     *
-     * <p>Once {@code build()} has been called, the {@code Builder} will no
-     * longer be usable.  Calling any method after {@code build()} will result
-     * in undefined behavior and can cause an
-     * {@code UnsupportedOperationException} to be thrown.
-     *
-     * <p>For use by generated code only.
-     */
-    public UnknownFieldSetLite build() {
-      if (set == null) {
-        return DEFAULT_INSTANCE;
-      }
-      
-      set.checkMutable();
-      set.makeImmutable();
-
-      return set;
-    }
-  }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/UnsafeByteOperations.java b/java/core/src/main/java/com/google/protobuf/UnsafeByteOperations.java
index f443ee39..0fbf4d40 100644
--- a/java/core/src/main/java/com/google/protobuf/UnsafeByteOperations.java
+++ b/java/core/src/main/java/com/google/protobuf/UnsafeByteOperations.java
@@ -30,6 +30,7 @@
 
 package com.google.protobuf;
 
+import java.io.IOException;
 import java.nio.ByteBuffer;
 
 /**
@@ -49,8 +50,8 @@ public final class UnsafeByteOperations {
   /**
    * An unsafe operation that returns a {@link ByteString} that is backed by the provided buffer.
    *
-   * @param buffer the Java NIO buffer to be wrapped.
-   * @return a {@link ByteString} backed by the provided buffer.
+   * @param buffer the Java NIO buffer to be wrapped
+   * @return a {@link ByteString} backed by the provided buffer
    */
   public static ByteString unsafeWrap(ByteBuffer buffer) {
     if (buffer.hasArray()) {
@@ -60,4 +61,24 @@ public final class UnsafeByteOperations {
       return new NioByteString(buffer);
     }
   }
+
+  /**
+   * Writes the given {@link ByteString} to the provided {@link ByteOutput}. Calling this method may
+   * result in multiple operations on the target {@link ByteOutput}
+   * (i.e. for roped {@link ByteString}s).
+   *
+   * <p>This method exposes the internal backing buffer(s) of the {@link ByteString} to the {@link
+   * ByteOutput} in order to avoid additional copying overhead. It would be possible for a malicious
+   * {@link ByteOutput} to corrupt the {@link ByteString}. Use with caution!
+   *
+   * <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 bytes the {@link ByteString} to be written
+   * @param  output  the output to receive the bytes
+   * @throws IOException  if an I/O error occurs
+   */
+  public static void unsafeWriteTo(ByteString bytes, ByteOutput output) throws IOException {
+    bytes.writeTo(output);
+  }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/Utf8.java b/java/core/src/main/java/com/google/protobuf/Utf8.java
index 48c7e9e6..308c69e9 100644
--- a/java/core/src/main/java/com/google/protobuf/Utf8.java
+++ b/java/core/src/main/java/com/google/protobuf/Utf8.java
@@ -30,6 +30,19 @@
 
 package com.google.protobuf;
 
+import static java.lang.Character.MAX_SURROGATE;
+import static java.lang.Character.MIN_SURROGATE;
+import static java.lang.Character.isSurrogatePair;
+import static java.lang.Character.toCodePoint;
+
+import java.lang.reflect.Field;
+import java.nio.Buffer;
+import java.nio.ByteBuffer;
+import java.security.AccessController;
+import java.security.PrivilegedExceptionAction;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
 /**
  * A set of low-level, high-performance static utility methods related
  * to the UTF-8 character encoding.  This class has no dependencies
@@ -64,9 +77,24 @@ package com.google.protobuf;
  *
  * @author martinrb@google.com (Martin Buchholz)
  */
+// TODO(nathanmittler): Copy changes in this class back to Guava
 final class Utf8 {
-  private Utf8() {}
-  
+  private static final Logger logger = Logger.getLogger(Utf8.class.getName());
+
+  /**
+   * UTF-8 is a runtime hot spot so we attempt to provide heavily optimized implementations
+   * depending on what is available on the platform. The processor is the platform-optimized
+   * delegate for which all methods are delegated directly to.
+   */
+  private static final Processor processor =
+      UnsafeProcessor.isAvailable() ? new UnsafeProcessor() : new SafeProcessor();
+
+  /**
+   * A mask used when performing unsafe reads to determine if a long value contains any non-ASCII
+   * characters (i.e. any byte >= 0x80).
+   */
+  private static final long ASCII_MASK_LONG = 0x8080808080808080L;
+
   /**
    * Maximum number of bytes per Java UTF-16 char in UTF-8.
    * @see java.nio.charset.CharsetEncoder#maxBytesPerChar()
@@ -85,6 +113,18 @@ final class Utf8 {
    */
   public static final int MALFORMED = -1;
 
+  /**
+   * Used by {@code Unsafe} UTF-8 string validation logic to determine the minimum string length
+   * above which to employ an optimized algorithm for counting ASCII characters. The reason for this
+   * threshold is that for small strings, the optimization may not be beneficial or may even
+   * negatively impact performance since it requires additional logic to avoid unaligned reads
+   * (when calling {@code Unsafe.getLong}). This threshold guarantees that even if the initial
+   * offset is unaligned, we're guaranteed to make at least one call to {@code Unsafe.getLong()}
+   * which provides a performance improvement that entirely subsumes the cost of the additional
+   * logic.
+   */
+  private static final int UNSAFE_COUNT_ASCII_THRESHOLD = 16;
+
   // Other state values include the partial bytes of the incomplete
   // character to be decoded in the simplest way: we pack the bytes
   // into the state int in little-endian order.  For example:
@@ -112,7 +152,7 @@ final class Utf8 {
    * isValidUtf8(bytes, 0, bytes.length)}.
    */
   public static boolean isValidUtf8(byte[] bytes) {
-    return isValidUtf8(bytes, 0, bytes.length);
+    return processor.isValidUtf8(bytes, 0, bytes.length);
   }
 
   /**
@@ -125,7 +165,7 @@ final class Utf8 {
    * partialIsValidUtf8(bytes, index, limit) == Utf8.COMPLETE}.
    */
   public static boolean isValidUtf8(byte[] bytes, int index, int limit) {
-    return partialIsValidUtf8(bytes, index, limit) == COMPLETE;
+    return processor.isValidUtf8(bytes, index, limit);
   }
 
   /**
@@ -146,183 +186,8 @@ final class Utf8 {
    * decode the character when passed to a subsequent invocation of a
    * partial decoding method.
    */
-  public static int partialIsValidUtf8(
-      int state, byte[] bytes, int index, int limit) {
-    if (state != COMPLETE) {
-      // The previous decoding operation was incomplete (or malformed).
-      // We look for a well-formed sequence consisting of bytes from
-      // the previous decoding operation (stored in state) together
-      // with bytes from the array slice.
-      //
-      // We expect such "straddler characters" to be rare.
-
-      if (index >= limit) {  // No bytes? No progress.
-        return state;
-      }
-      int byte1 = (byte) state;
-      // byte1 is never ASCII.
-      if (byte1 < (byte) 0xE0) {
-        // two-byte form
-
-        // Simultaneously checks for illegal trailing-byte in
-        // leading position and overlong 2-byte form.
-        if (byte1 < (byte) 0xC2 ||
-            // byte2 trailing-byte test
-            bytes[index++] > (byte) 0xBF) {
-          return MALFORMED;
-        }
-      } else if (byte1 < (byte) 0xF0) {
-        // three-byte form
-
-        // Get byte2 from saved state or array
-        int byte2 = (byte) ~(state >> 8);
-        if (byte2 == 0) {
-          byte2 = bytes[index++];
-          if (index >= limit) {
-            return incompleteStateFor(byte1, byte2);
-          }
-        }
-        if (byte2 > (byte) 0xBF ||
-            // overlong? 5 most significant bits must not all be zero
-            (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0) ||
-            // illegal surrogate codepoint?
-            (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0) ||
-            // byte3 trailing-byte test
-            bytes[index++] > (byte) 0xBF) {
-          return MALFORMED;
-        }
-      } else {
-        // four-byte form
-
-        // Get byte2 and byte3 from saved state or array
-        int byte2 = (byte) ~(state >> 8);
-        int byte3 = 0;
-        if (byte2 == 0) {
-          byte2 = bytes[index++];
-          if (index >= limit) {
-            return incompleteStateFor(byte1, byte2);
-          }
-        } else {
-          byte3 = (byte) (state >> 16);
-        }
-        if (byte3 == 0) {
-          byte3 = bytes[index++];
-          if (index >= limit) {
-            return incompleteStateFor(byte1, byte2, byte3);
-          }
-        }
-
-        // If we were called with state == MALFORMED, then byte1 is 0xFF,
-        // which never occurs in well-formed UTF-8, and so we will return
-        // MALFORMED again below.
-
-        if (byte2 > (byte) 0xBF ||
-            // Check that 1 <= plane <= 16.  Tricky optimized form of:
-            // if (byte1 > (byte) 0xF4 ||
-            //     byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 ||
-            //     byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
-            (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0 ||
-            // byte3 trailing-byte test
-            byte3 > (byte) 0xBF ||
-            // byte4 trailing-byte test
-             bytes[index++] > (byte) 0xBF) {
-          return MALFORMED;
-        }
-      }
-    }
-
-    return partialIsValidUtf8(bytes, index, limit);
-  }
-
-  /**
-   * Tells whether the given byte array slice is a well-formed,
-   * malformed, or incomplete UTF-8 byte sequence.  The range of bytes
-   * to be checked extends from index {@code index}, inclusive, to
-   * {@code limit}, exclusive.
-   *
-   * <p>This is a convenience method, equivalent to a call to {@code
-   * partialIsValidUtf8(Utf8.COMPLETE, bytes, index, limit)}.
-   *
-   * @return {@link #MALFORMED} if the partial byte sequence is
-   * definitely not well-formed, {@link #COMPLETE} if it is well-formed
-   * (no additional input needed), or if the byte sequence is
-   * "incomplete", i.e. apparently terminated in the middle of a character,
-   * an opaque integer "state" value containing enough information to
-   * decode the character when passed to a subsequent invocation of a
-   * partial decoding method.
-   */
-  public static int partialIsValidUtf8(
-      byte[] bytes, int index, int limit) {
-    // Optimize for 100% ASCII.
-    // Hotspot loves small simple top-level loops like this.
-    while (index < limit && bytes[index] >= 0) {
-      index++;
-    }
-
-    return (index >= limit) ? COMPLETE :
-        partialIsValidUtf8NonAscii(bytes, index, limit);
-  }
-
-  private static int partialIsValidUtf8NonAscii(
-      byte[] bytes, int index, int limit) {
-    for (;;) {
-      int byte1, byte2;
-
-      // Optimize for interior runs of ASCII bytes.
-      do {
-        if (index >= limit) {
-          return COMPLETE;
-        }
-      } while ((byte1 = bytes[index++]) >= 0);
-
-      if (byte1 < (byte) 0xE0) {
-        // two-byte form
-
-        if (index >= limit) {
-          return byte1;
-        }
-
-        // Simultaneously checks for illegal trailing-byte in
-        // leading position and overlong 2-byte form.
-        if (byte1 < (byte) 0xC2 ||
-            bytes[index++] > (byte) 0xBF) {
-          return MALFORMED;
-        }
-      } else if (byte1 < (byte) 0xF0) {
-        // three-byte form
-
-        if (index >= limit - 1) { // incomplete sequence
-          return incompleteStateFor(bytes, index, limit);
-        }
-        if ((byte2 = bytes[index++]) > (byte) 0xBF ||
-            // overlong? 5 most significant bits must not all be zero
-            (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0) ||
-            // check for illegal surrogate codepoints
-            (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0) ||
-            // byte3 trailing-byte test
-            bytes[index++] > (byte) 0xBF) {
-          return MALFORMED;
-        }
-      } else {
-        // four-byte form
-
-        if (index >= limit - 2) {  // incomplete sequence
-          return incompleteStateFor(bytes, index, limit);
-        }
-        if ((byte2 = bytes[index++]) > (byte) 0xBF ||
-            // Check that 1 <= plane <= 16.  Tricky optimized form of:
-            // if (byte1 > (byte) 0xF4 ||
-            //     byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 ||
-            //     byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
-            (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0 ||
-            // byte3 trailing-byte test
-            bytes[index++] > (byte) 0xBF ||
-            // byte4 trailing-byte test
-            bytes[index++] > (byte) 0xBF) {
-          return MALFORMED;
-        }
-      }
-    }
+  public static int partialIsValidUtf8(int state, byte[] bytes, int index, int limit) {
+    return processor.partialIsValidUtf8(state, bytes, index, limit);
   }
 
   private static int incompleteStateFor(int byte1) {
@@ -352,19 +217,31 @@ final class Utf8 {
       default: throw new AssertionError();
     }
   }
-  
+
+  private static int incompleteStateFor(
+      final ByteBuffer buffer, final int byte1, final int index, final int remaining) {
+    switch (remaining) {
+      case 0:
+        return incompleteStateFor(byte1);
+      case 1:
+        return incompleteStateFor(byte1, buffer.get(index));
+      case 2:
+        return incompleteStateFor(byte1, buffer.get(index), buffer.get(index + 1));
+      default:
+        throw new AssertionError();
+    }
+  }
 
   // These UTF-8 handling methods are copied from Guava's Utf8 class with a modification to throw
   // a protocol buffer local exception. This exception is then caught in CodedOutputStream so it can
   // fallback to more lenient behavior.
   
   static class UnpairedSurrogateException extends IllegalArgumentException {
-    
     private UnpairedSurrogateException(int index, int length) {
       super("Unpaired surrogate at index " + index + " of " + length);
     }
   }
-  
+
   /**
    * Returns the number of bytes in the UTF-8-encoded form of {@code sequence}. For a string,
    * this method is equivalent to {@code string.getBytes(UTF_8).length}, but is more efficient in
@@ -426,56 +303,1381 @@ final class Utf8 {
     return utf8Length;
   }
 
-  static int encode(CharSequence sequence, byte[] bytes, int offset, int length) {
-    int utf16Length = sequence.length();
-    int j = offset;
-    int i = 0;
-    int limit = offset + length;
-    // Designed to take advantage of
-    // https://wikis.oracle.com/display/HotSpotInternals/RangeCheckElimination
-    for (char c; i < utf16Length && i + j < limit && (c = sequence.charAt(i)) < 0x80; i++) {
-      bytes[j + i] = (byte) c;
-    }
-    if (i == utf16Length) {
-      return j + utf16Length;
-    }
-    j += i;
-    for (char c; i < utf16Length; i++) {
-      c = sequence.charAt(i);
-      if (c < 0x80 && j < limit) {
-        bytes[j++] = (byte) c;
-      } else if (c < 0x800 && j <= limit - 2) { // 11 bits, two UTF-8 bytes
-        bytes[j++] = (byte) ((0xF << 6) | (c >>> 6));
-        bytes[j++] = (byte) (0x80 | (0x3F & c));
-      } else if ((c < Character.MIN_SURROGATE || Character.MAX_SURROGATE < c) && j <= limit - 3) {
-        // Maximum single-char code point is 0xFFFF, 16 bits, three UTF-8 bytes
-        bytes[j++] = (byte) ((0xF << 5) | (c >>> 12));
-        bytes[j++] = (byte) (0x80 | (0x3F & (c >>> 6)));
-        bytes[j++] = (byte) (0x80 | (0x3F & c));
-      } else if (j <= limit - 4) {
-        // Minimum code point represented by a surrogate pair is 0x10000, 17 bits, four UTF-8 bytes
-        final char low;
-        if (i + 1 == sequence.length()
-                || !Character.isSurrogatePair(c, (low = sequence.charAt(++i)))) {
-          throw new UnpairedSurrogateException((i - 1), utf16Length);
-        }
-        int codePoint = Character.toCodePoint(c, low);
-        bytes[j++] = (byte) ((0xF << 4) | (codePoint >>> 18));
-        bytes[j++] = (byte) (0x80 | (0x3F & (codePoint >>> 12)));
-        bytes[j++] = (byte) (0x80 | (0x3F & (codePoint >>> 6)));
-        bytes[j++] = (byte) (0x80 | (0x3F & codePoint));
+  static int encode(CharSequence in, byte[] out, int offset, int length) {
+    return processor.encodeUtf8(in, out, offset, length);
+  }
+  // End Guava UTF-8 methods.
+
+  /**
+   * Determines if the given {@link ByteBuffer} is a valid UTF-8 string.
+   *
+   * <p>Selects an optimal algorithm based on the type of {@link ByteBuffer} (i.e. heap or direct)
+   * and the capabilities of the platform.
+   *
+   * @param buffer the buffer to check.
+   * @see Utf8#isValidUtf8(byte[], int, int)
+   */
+  static boolean isValidUtf8(ByteBuffer buffer) {
+    return processor.isValidUtf8(buffer, buffer.position(), buffer.remaining());
+  }
+
+  /**
+   * Determines if the given {@link ByteBuffer} is a partially valid UTF-8 string.
+   *
+   * <p>Selects an optimal algorithm based on the type of {@link ByteBuffer} (i.e. heap or direct)
+   * and the capabilities of the platform.
+   *
+   * @param buffer the buffer to check.
+   * @see Utf8#partialIsValidUtf8(int, byte[], int, int)
+   */
+  static int partialIsValidUtf8(int state, ByteBuffer buffer, int index, int limit) {
+    return processor.partialIsValidUtf8(state, buffer, index, limit);
+  }
+
+  /**
+   * Encodes the given characters to the target {@link ByteBuffer} using UTF-8 encoding.
+   *
+   * <p>Selects an optimal algorithm based on the type of {@link ByteBuffer} (i.e. heap or direct)
+   * and the capabilities of the platform.
+   *
+   * @param in the source string to be encoded
+   * @param out the target buffer to receive the encoded string.
+   * @see Utf8#encode(CharSequence, byte[], int, int)
+   */
+  static void encodeUtf8(CharSequence in, ByteBuffer out) {
+    processor.encodeUtf8(in, out);
+  }
+
+  /**
+   * Counts (approximately) the number of consecutive ASCII characters in the given buffer.
+   * The byte order of the {@link ByteBuffer} does not matter, so performance can be improved if
+   * native byte order is used (i.e. no byte-swapping in {@link ByteBuffer#getLong(int)}).
+   *
+   * @param buffer the buffer to be scanned for ASCII chars
+   * @param index the starting index of the scan
+   * @param limit the limit within buffer for the scan
+   * @return the number of ASCII characters found. The stopping position will be at or
+   * before the first non-ASCII byte.
+   */
+  private static int estimateConsecutiveAscii(ByteBuffer buffer, int index, int limit) {
+    int i = index;
+    final int lim = limit - 7;
+    // This simple loop stops when we encounter a byte >= 0x80 (i.e. non-ASCII).
+    // To speed things up further, we're reading longs instead of bytes so we use a mask to
+    // determine if any byte in the current long is non-ASCII.
+    for (; i < lim && (buffer.getLong(i) & ASCII_MASK_LONG) == 0; i += 8) {}
+    return i - index;
+  }
+
+  /**
+   * A processor of UTF-8 strings, providing methods for checking validity and encoding.
+   */
+  // TODO(nathanmittler): Add support for Memory/MemoryBlock on Android.
+  abstract static class Processor {
+    /**
+     * Returns {@code true} if the given byte array slice is a
+     * well-formed UTF-8 byte sequence.  The range of bytes to be
+     * checked extends from index {@code index}, inclusive, to {@code
+     * limit}, exclusive.
+     *
+     * <p>This is a convenience method, equivalent to {@code
+     * partialIsValidUtf8(bytes, index, limit) == Utf8.COMPLETE}.
+     */
+    final boolean isValidUtf8(byte[] bytes, int index, int limit) {
+      return partialIsValidUtf8(COMPLETE, bytes, index, limit) == COMPLETE;
+    }
+
+    /**
+     * Tells whether the given byte array slice is a well-formed,
+     * malformed, or incomplete UTF-8 byte sequence.  The range of bytes
+     * to be checked extends from index {@code index}, inclusive, to
+     * {@code limit}, exclusive.
+     *
+     * @param state either {@link Utf8#COMPLETE} (if this is the initial decoding
+     * operation) or the value returned from a call to a partial decoding method
+     * for the previous bytes
+     *
+     * @return {@link #MALFORMED} if the partial byte sequence is
+     * definitely not well-formed, {@link #COMPLETE} if it is well-formed
+     * (no additional input needed), or if the byte sequence is
+     * "incomplete", i.e. apparently terminated in the middle of a character,
+     * an opaque integer "state" value containing enough information to
+     * decode the character when passed to a subsequent invocation of a
+     * partial decoding method.
+     */
+    abstract int partialIsValidUtf8(int state, byte[] bytes, int index, int limit);
+
+    /**
+     * Returns {@code true} if the given portion of the {@link ByteBuffer} is a
+     * well-formed UTF-8 byte sequence.  The range of bytes to be
+     * checked extends from index {@code index}, inclusive, to {@code
+     * limit}, exclusive.
+     *
+     * <p>This is a convenience method, equivalent to {@code
+     * partialIsValidUtf8(bytes, index, limit) == Utf8.COMPLETE}.
+     */
+    final boolean isValidUtf8(ByteBuffer buffer, int index, int limit) {
+      return partialIsValidUtf8(COMPLETE, buffer, index, limit) == COMPLETE;
+    }
+
+    /**
+     * Indicates whether or not the given buffer contains a valid UTF-8 string.
+     *
+     * @param buffer the buffer to check.
+     * @return {@code true} if the given buffer contains a valid UTF-8 string.
+     */
+    final int partialIsValidUtf8(
+        final int state, final ByteBuffer buffer, int index, final int limit) {
+      if (buffer.hasArray()) {
+        final int offset = buffer.arrayOffset();
+        return partialIsValidUtf8(state, buffer.array(), offset + index, offset + limit);
+      } else if (buffer.isDirect()){
+        return partialIsValidUtf8Direct(state, buffer, index, limit);
+      }
+      return partialIsValidUtf8Default(state, buffer, index, limit);
+    }
+
+    /**
+     * Performs validation for direct {@link ByteBuffer} instances.
+     */
+    abstract int partialIsValidUtf8Direct(
+        final int state, final ByteBuffer buffer, int index, final int limit);
+
+    /**
+     * Performs validation for {@link ByteBuffer} instances using the {@link ByteBuffer} API rather
+     * than potentially faster approaches. This first completes validation for the current
+     * character (provided by {@code state}) and then finishes validation for the sequence.
+     */
+    final int partialIsValidUtf8Default(
+        final int state, final ByteBuffer buffer, int index, final int limit) {
+      if (state != COMPLETE) {
+        // The previous decoding operation was incomplete (or malformed).
+        // We look for a well-formed sequence consisting of bytes from
+        // the previous decoding operation (stored in state) together
+        // with bytes from the array slice.
+        //
+        // We expect such "straddler characters" to be rare.
+
+        if (index >= limit) { // No bytes? No progress.
+          return state;
+        }
+
+        byte byte1 = (byte) state;
+        // byte1 is never ASCII.
+        if (byte1 < (byte) 0xE0) {
+          // two-byte form
+
+          // Simultaneously checks for illegal trailing-byte in
+          // leading position and overlong 2-byte form.
+          if (byte1 < (byte) 0xC2
+              // byte2 trailing-byte test
+              || buffer.get(index++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else if (byte1 < (byte) 0xF0) {
+          // three-byte form
+
+          // Get byte2 from saved state or array
+          byte byte2 = (byte) ~(state >> 8);
+          if (byte2 == 0) {
+            byte2 = buffer.get(index++);
+            if (index >= limit) {
+              return incompleteStateFor(byte1, byte2);
+            }
+          }
+          if (byte2 > (byte) 0xBF
+              // overlong? 5 most significant bits must not all be zero
+              || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
+              // illegal surrogate codepoint?
+              || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
+              // byte3 trailing-byte test
+              || buffer.get(index++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else {
+          // four-byte form
+
+          // Get byte2 and byte3 from saved state or array
+          byte byte2 = (byte) ~(state >> 8);
+          byte byte3 = 0;
+          if (byte2 == 0) {
+            byte2 = buffer.get(index++);
+            if (index >= limit) {
+              return incompleteStateFor(byte1, byte2);
+            }
+          } else {
+            byte3 = (byte) (state >> 16);
+          }
+          if (byte3 == 0) {
+            byte3 = buffer.get(index++);
+            if (index >= limit) {
+              return incompleteStateFor(byte1, byte2, byte3);
+            }
+          }
+
+          // If we were called with state == MALFORMED, then byte1 is 0xFF,
+          // which never occurs in well-formed UTF-8, and so we will return
+          // MALFORMED again below.
+
+          if (byte2 > (byte) 0xBF
+              // Check that 1 <= plane <= 16.  Tricky optimized form of:
+              // if (byte1 > (byte) 0xF4 ||
+              //     byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 ||
+              //     byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
+              || (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0
+              // byte3 trailing-byte test
+              || byte3 > (byte) 0xBF
+              // byte4 trailing-byte test
+              || buffer.get(index++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        }
+      }
+
+      // Finish validation for the sequence.
+      return partialIsValidUtf8(buffer, index, limit);
+    }
+
+    /**
+     * Performs validation for {@link ByteBuffer} instances using the {@link ByteBuffer} API rather
+     * than potentially faster approaches.
+     */
+    private static int partialIsValidUtf8(final ByteBuffer buffer, int index, final int limit) {
+      index += estimateConsecutiveAscii(buffer, index, limit);
+
+      for (;;) {
+        // Optimize for interior runs of ASCII bytes.
+        // TODO(nathanmittler): Consider checking 8 bytes at a time after some threshold?
+        // Maybe after seeing a few in a row that are ASCII, go back to fast mode?
+        int byte1;
+        do {
+          if (index >= limit) {
+            return COMPLETE;
+          }
+        } while ((byte1 = buffer.get(index++)) >= 0);
+
+        // If we're here byte1 is not ASCII. Only need to handle 2-4 byte forms.
+        if (byte1 < (byte) 0xE0) {
+          // Two-byte form (110xxxxx 10xxxxxx)
+          if (index >= limit) {
+            // Incomplete sequence
+            return byte1;
+          }
+
+          // Simultaneously checks for illegal trailing-byte in
+          // leading position and overlong 2-byte form.
+          if (byte1 < (byte) 0xC2 || buffer.get(index) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+          index++;
+        } else if (byte1 < (byte) 0xF0) {
+          // Three-byte form (1110xxxx 10xxxxxx 10xxxxxx)
+          if (index >= limit - 1) {
+            // Incomplete sequence
+            return incompleteStateFor(buffer, byte1, index, limit - index);
+          }
+
+          final byte byte2 = buffer.get(index++);
+          if (byte2 > (byte) 0xBF
+              // overlong? 5 most significant bits must not all be zero
+              || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
+              // check for illegal surrogate codepoints
+              || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
+              // byte3 trailing-byte test
+              || buffer.get(index) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+          index++;
+        } else {
+          // Four-byte form (1110xxxx 10xxxxxx 10xxxxxx 10xxxxxx)
+          if (index >= limit - 2) {
+            // Incomplete sequence
+            return incompleteStateFor(buffer, byte1, index, limit - index);
+          }
+
+          // TODO(nathanmittler): Consider using getInt() to improve performance.
+          final int byte2 = buffer.get(index++);
+          if (byte2 > (byte) 0xBF
+              // Check that 1 <= plane <= 16.  Tricky optimized form of:
+              // if (byte1 > (byte) 0xF4 ||
+              //     byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 ||
+              //     byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
+              || (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0
+              // byte3 trailing-byte test
+              || buffer.get(index++) > (byte) 0xBF
+              // byte4 trailing-byte test
+              || buffer.get(index++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        }
+      }
+    }
+
+    /**
+     * Encodes an input character sequence ({@code in}) to UTF-8 in the target array ({@code out}).
+     * For a string, this method is similar to
+     * <pre>{@code
+     * byte[] a = string.getBytes(UTF_8);
+     * System.arraycopy(a, 0, bytes, offset, a.length);
+     * return offset + a.length;
+     * }</pre>
+     *
+     * but is more efficient in both time and space. One key difference is that this method
+     * requires paired surrogates, and therefore does not support chunking.
+     * While {@code String.getBytes(UTF_8)} replaces unpaired surrogates with the default
+     * replacement character, this method throws {@link UnpairedSurrogateException}.
+     *
+     * <p>To ensure sufficient space in the output buffer, either call {@link #encodedLength} to
+     * compute the exact amount needed, or leave room for 
+     * {@code Utf8.MAX_BYTES_PER_CHAR * sequence.length()}, which is the largest possible number
+     * of bytes that any input can be encoded to.
+     *
+     * @param in the input character sequence to be encoded
+     * @param out the target array
+     * @param offset the starting offset in {@code bytes} to start writing at
+     * @param length the length of the {@code bytes}, starting from {@code offset}
+     * @throws UnpairedSurrogateException if {@code sequence} contains ill-formed UTF-16 (unpaired
+     *     surrogates)
+     * @throws ArrayIndexOutOfBoundsException if {@code sequence} encoded in UTF-8 is longer than
+     *     {@code bytes.length - offset}
+     * @return the new offset, equivalent to {@code offset + Utf8.encodedLength(sequence)}
+     */
+    abstract int encodeUtf8(CharSequence in, byte[] out, int offset, int length);
+
+    /**
+     * Encodes an input character sequence ({@code in}) to UTF-8 in the target buffer ({@code out}).
+     * Upon returning from this method, the {@code out} position will point to the position after
+     * the last encoded byte. This method requires paired surrogates, and therefore does not
+     * support chunking.
+     *
+     * <p>To ensure sufficient space in the output buffer, either call {@link #encodedLength} to
+     * compute the exact amount needed, or leave room for
+     * {@code Utf8.MAX_BYTES_PER_CHAR * in.length()}, which is the largest possible number
+     * of bytes that any input can be encoded to.
+     *
+     * @param in the source character sequence to be encoded
+     * @param out the target buffer
+     * @throws UnpairedSurrogateException if {@code in} contains ill-formed UTF-16 (unpaired
+     *     surrogates)
+     * @throws ArrayIndexOutOfBoundsException if {@code in} encoded in UTF-8 is longer than
+     *     {@code out.remaining()}
+     */
+    final void encodeUtf8(CharSequence in, ByteBuffer out) {
+      if (out.hasArray()) {
+        final int offset = out.arrayOffset();
+        int endIndex =
+            Utf8.encode(in, out.array(), offset + out.position(), out.remaining());
+        out.position(endIndex - offset);
+      } else if (out.isDirect()) {
+        encodeUtf8Direct(in, out);
       } else {
-        // If we are surrogates and we're not a surrogate pair, always throw an
-        // IllegalArgumentException instead of an ArrayOutOfBoundsException.
-        if ((Character.MIN_SURROGATE <= c && c <= Character.MAX_SURROGATE)
-            && (i + 1 == sequence.length()
-                || !Character.isSurrogatePair(c, sequence.charAt(i + 1)))) {
-          throw new UnpairedSurrogateException(i, utf16Length);
+        encodeUtf8Default(in, out);
+      }
+    }
+
+    /**
+     * Encodes the input character sequence to a direct {@link ByteBuffer} instance.
+     */
+    abstract void encodeUtf8Direct(CharSequence in, ByteBuffer out);
+
+    /**
+     * Encodes the input character sequence to a {@link ByteBuffer} instance using the {@link
+     * ByteBuffer} API, rather than potentially faster approaches.
+     */
+    final void encodeUtf8Default(CharSequence in, ByteBuffer out) {
+      final int inLength = in.length();
+      int outIx = out.position();
+      int inIx = 0;
+
+      // Since ByteBuffer.putXXX() already checks boundaries for us, no need to explicitly check
+      // access. Assume the buffer is big enough and let it handle the out of bounds exception
+      // if it occurs.
+      try {
+        // Designed to take advantage of
+        // https://wikis.oracle.com/display/HotSpotInternals/RangeCheckElimination
+        for (char c; inIx < inLength && (c = in.charAt(inIx)) < 0x80; ++inIx) {
+          out.put(outIx + inIx, (byte) c);
         }
-        throw new ArrayIndexOutOfBoundsException("Failed writing " + c + " at index " + j);
+        if (inIx == inLength) {
+          // Successfully encoded the entire string.
+          out.position(outIx + inIx);
+          return;
+        }
+
+        outIx += inIx;
+        for (char c; inIx < inLength; ++inIx, ++outIx) {
+          c = in.charAt(inIx);
+          if (c < 0x80) {
+            // One byte (0xxx xxxx)
+            out.put(outIx, (byte) c);
+          } else if (c < 0x800) {
+            // Two bytes (110x xxxx 10xx xxxx)
+
+            // Benchmarks show put performs better than putShort here (for HotSpot).
+            out.put(outIx++, (byte) (0xC0 | (c >>> 6)));
+            out.put(outIx, (byte) (0x80 | (0x3F & c)));
+          } else if (c < MIN_SURROGATE || MAX_SURROGATE < c) {
+            // Three bytes (1110 xxxx 10xx xxxx 10xx xxxx)
+            // Maximum single-char code point is 0xFFFF, 16 bits.
+
+            // Benchmarks show put performs better than putShort here (for HotSpot).
+            out.put(outIx++, (byte) (0xE0 | (c >>> 12)));
+            out.put(outIx++, (byte) (0x80 | (0x3F & (c >>> 6))));
+            out.put(outIx, (byte) (0x80 | (0x3F & c)));
+          } else {
+            // Four bytes (1111 xxxx 10xx xxxx 10xx xxxx 10xx xxxx)
+
+            // Minimum code point represented by a surrogate pair is 0x10000, 17 bits, four UTF-8
+            // bytes
+            final char low;
+            if (inIx + 1 == inLength || !isSurrogatePair(c, (low = in.charAt(++inIx)))) {
+              throw new UnpairedSurrogateException(inIx, inLength);
+            }
+            // TODO(nathanmittler): Consider using putInt() to improve performance.
+            int codePoint = toCodePoint(c, low);
+            out.put(outIx++, (byte) ((0xF << 4) | (codePoint >>> 18)));
+            out.put(outIx++, (byte) (0x80 | (0x3F & (codePoint >>> 12))));
+            out.put(outIx++, (byte) (0x80 | (0x3F & (codePoint >>> 6))));
+            out.put(outIx, (byte) (0x80 | (0x3F & codePoint)));
+          }
+        }
+
+        // Successfully encoded the entire string.
+        out.position(outIx);
+      } catch (IndexOutOfBoundsException e) {
+        // TODO(nathanmittler): Consider making the API throw IndexOutOfBoundsException instead.
+
+        // If we failed in the outer ASCII loop, outIx will not have been updated. In this case,
+        // use inIx to determine the bad write index.
+        int badWriteIndex = out.position() + Math.max(inIx, outIx - out.position() + 1);
+        throw new ArrayIndexOutOfBoundsException(
+            "Failed writing " + in.charAt(inIx) + " at index " + badWriteIndex);
       }
     }
-    return j;
   }
-  // End Guava UTF-8 methods.
+
+  /**
+   * {@link Processor} implementation that does not use any {@code sun.misc.Unsafe} methods.
+   */
+  static final class SafeProcessor extends Processor {
+    @Override
+    int partialIsValidUtf8(int state, byte[] bytes, int index, int limit) {
+      if (state != COMPLETE) {
+        // The previous decoding operation was incomplete (or malformed).
+        // We look for a well-formed sequence consisting of bytes from
+        // the previous decoding operation (stored in state) together
+        // with bytes from the array slice.
+        //
+        // We expect such "straddler characters" to be rare.
+
+        if (index >= limit) {  // No bytes? No progress.
+          return state;
+        }
+        int byte1 = (byte) state;
+        // byte1 is never ASCII.
+        if (byte1 < (byte) 0xE0) {
+          // two-byte form
+
+          // Simultaneously checks for illegal trailing-byte in
+          // leading position and overlong 2-byte form.
+          if (byte1 < (byte) 0xC2
+              // byte2 trailing-byte test
+              || bytes[index++] > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else if (byte1 < (byte) 0xF0) {
+          // three-byte form
+
+          // Get byte2 from saved state or array
+          int byte2 = (byte) ~(state >> 8);
+          if (byte2 == 0) {
+            byte2 = bytes[index++];
+            if (index >= limit) {
+              return incompleteStateFor(byte1, byte2);
+            }
+          }
+          if (byte2 > (byte) 0xBF
+              // overlong? 5 most significant bits must not all be zero
+              || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
+              // illegal surrogate codepoint?
+              || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
+              // byte3 trailing-byte test
+              || bytes[index++] > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else {
+          // four-byte form
+
+          // Get byte2 and byte3 from saved state or array
+          int byte2 = (byte) ~(state >> 8);
+          int byte3 = 0;
+          if (byte2 == 0) {
+            byte2 = bytes[index++];
+            if (index >= limit) {
+              return incompleteStateFor(byte1, byte2);
+            }
+          } else {
+            byte3 = (byte) (state >> 16);
+          }
+          if (byte3 == 0) {
+            byte3 = bytes[index++];
+            if (index >= limit) {
+              return incompleteStateFor(byte1, byte2, byte3);
+            }
+          }
+
+          // If we were called with state == MALFORMED, then byte1 is 0xFF,
+          // which never occurs in well-formed UTF-8, and so we will return
+          // MALFORMED again below.
+
+          if (byte2 > (byte) 0xBF
+              // Check that 1 <= plane <= 16.  Tricky optimized form of:
+              // if (byte1 > (byte) 0xF4 ||
+              //     byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 ||
+              //     byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
+              || (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0
+              // byte3 trailing-byte test
+              || byte3 > (byte) 0xBF
+              // byte4 trailing-byte test
+              || bytes[index++] > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        }
+      }
+
+      return partialIsValidUtf8(bytes, index, limit);
+    }
+
+    @Override
+    int partialIsValidUtf8Direct(int state, ByteBuffer buffer, int index, int limit) {
+      // For safe processing, we have to use the ByteBuffer API.
+      return partialIsValidUtf8Default(state, buffer, index, limit);
+    }
+
+    @Override
+    int encodeUtf8(CharSequence in, byte[] out, int offset, int length) {
+      int utf16Length = in.length();
+      int j = offset;
+      int i = 0;
+      int limit = offset + length;
+      // Designed to take advantage of
+      // https://wikis.oracle.com/display/HotSpotInternals/RangeCheckElimination
+      for (char c; i < utf16Length && i + j < limit && (c = in.charAt(i)) < 0x80; i++) {
+        out[j + i] = (byte) c;
+      }
+      if (i == utf16Length) {
+        return j + utf16Length;
+      }
+      j += i;
+      for (char c; i < utf16Length; i++) {
+        c = in.charAt(i);
+        if (c < 0x80 && j < limit) {
+          out[j++] = (byte) c;
+        } else if (c < 0x800 && j <= limit - 2) { // 11 bits, two UTF-8 bytes
+          out[j++] = (byte) ((0xF << 6) | (c >>> 6));
+          out[j++] = (byte) (0x80 | (0x3F & c));
+        } else if ((c < Character.MIN_SURROGATE || Character.MAX_SURROGATE < c) && j <= limit - 3) {
+          // Maximum single-char code point is 0xFFFF, 16 bits, three UTF-8 bytes
+          out[j++] = (byte) ((0xF << 5) | (c >>> 12));
+          out[j++] = (byte) (0x80 | (0x3F & (c >>> 6)));
+          out[j++] = (byte) (0x80 | (0x3F & c));
+        } else if (j <= limit - 4) {
+          // Minimum code point represented by a surrogate pair is 0x10000, 17 bits,
+          // four UTF-8 bytes
+          final char low;
+          if (i + 1 == in.length()
+                  || !Character.isSurrogatePair(c, (low = in.charAt(++i)))) {
+            throw new UnpairedSurrogateException((i - 1), utf16Length);
+          }
+          int codePoint = Character.toCodePoint(c, low);
+          out[j++] = (byte) ((0xF << 4) | (codePoint >>> 18));
+          out[j++] = (byte) (0x80 | (0x3F & (codePoint >>> 12)));
+          out[j++] = (byte) (0x80 | (0x3F & (codePoint >>> 6)));
+          out[j++] = (byte) (0x80 | (0x3F & codePoint));
+        } else {
+          // If we are surrogates and we're not a surrogate pair, always throw an
+          // UnpairedSurrogateException instead of an ArrayOutOfBoundsException.
+          if ((Character.MIN_SURROGATE <= c && c <= Character.MAX_SURROGATE)
+              && (i + 1 == in.length()
+                  || !Character.isSurrogatePair(c, in.charAt(i + 1)))) {
+            throw new UnpairedSurrogateException(i, utf16Length);
+          }
+          throw new ArrayIndexOutOfBoundsException("Failed writing " + c + " at index " + j);
+        }
+      }
+      return j;
+    }
+
+    @Override
+    void encodeUtf8Direct(CharSequence in, ByteBuffer out) {
+      // For safe processing, we have to use the ByteBuffer API.
+      encodeUtf8Default(in, out);
+    }
+
+    private static int partialIsValidUtf8(byte[] bytes, int index, int limit) {
+      // Optimize for 100% ASCII (Hotspot loves small simple top-level loops like this).
+      // This simple loop stops when we encounter a byte >= 0x80 (i.e. non-ASCII).
+      while (index < limit && bytes[index] >= 0) {
+        index++;
+      }
+
+      return (index >= limit) ? COMPLETE : partialIsValidUtf8NonAscii(bytes, index, limit);
+    }
+
+    private static int partialIsValidUtf8NonAscii(byte[] bytes, int index, int limit) {
+      for (;;) {
+        int byte1, byte2;
+
+        // Optimize for interior runs of ASCII bytes.
+        do {
+          if (index >= limit) {
+            return COMPLETE;
+          }
+        } while ((byte1 = bytes[index++]) >= 0);
+
+        if (byte1 < (byte) 0xE0) {
+          // two-byte form
+
+          if (index >= limit) {
+            // Incomplete sequence
+            return byte1;
+          }
+
+          // Simultaneously checks for illegal trailing-byte in
+          // leading position and overlong 2-byte form.
+          if (byte1 < (byte) 0xC2
+              || bytes[index++] > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else if (byte1 < (byte) 0xF0) {
+          // three-byte form
+
+          if (index >= limit - 1) { // incomplete sequence
+            return incompleteStateFor(bytes, index, limit);
+          }
+          if ((byte2 = bytes[index++]) > (byte) 0xBF
+              // overlong? 5 most significant bits must not all be zero
+              || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
+              // check for illegal surrogate codepoints
+              || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
+              // byte3 trailing-byte test
+              || bytes[index++] > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else {
+          // four-byte form
+
+          if (index >= limit - 2) {  // incomplete sequence
+            return incompleteStateFor(bytes, index, limit);
+          }
+          if ((byte2 = bytes[index++]) > (byte) 0xBF
+              // Check that 1 <= plane <= 16.  Tricky optimized form of:
+              // if (byte1 > (byte) 0xF4 ||
+              //     byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 ||
+              //     byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
+              || (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0
+              // byte3 trailing-byte test
+              || bytes[index++] > (byte) 0xBF
+              // byte4 trailing-byte test
+              || bytes[index++] > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        }
+      }
+    }
+  }
+
+  /**
+   * {@link Processor} that uses {@code sun.misc.Unsafe} where possible to improve performance.
+   */
+  static final class UnsafeProcessor extends Processor {
+    private static final sun.misc.Unsafe UNSAFE = getUnsafe();
+    private static final long BUFFER_ADDRESS_OFFSET =
+        fieldOffset(field(Buffer.class, "address"));
+    private static final int ARRAY_BASE_OFFSET = byteArrayBaseOffset();
+
+    /**
+     * We only use Unsafe operations if we have access to direct {@link ByteBuffer}'s address
+     * and the array base offset is a multiple of 8 (needed by Unsafe.getLong()).
+     */
+    private static final boolean AVAILABLE =
+        BUFFER_ADDRESS_OFFSET != -1 && ARRAY_BASE_OFFSET % 8 == 0;
+
+    /**
+     * Indicates whether or not all required unsafe operations are supported on this platform.
+     */
+    static boolean isAvailable() {
+      return AVAILABLE;
+    }
+
+    @Override
+    int partialIsValidUtf8(int state, byte[] bytes, final int index, final int limit) {
+      if ((index | limit | bytes.length - limit) < 0) {
+        throw new ArrayIndexOutOfBoundsException(
+            String.format("Array length=%d, index=%d, limit=%d", bytes.length, index, limit));
+      }
+      long offset = ARRAY_BASE_OFFSET + index;
+      final long offsetLimit = ARRAY_BASE_OFFSET + limit;
+      if (state != COMPLETE) {
+        // The previous decoding operation was incomplete (or malformed).
+        // We look for a well-formed sequence consisting of bytes from
+        // the previous decoding operation (stored in state) together
+        // with bytes from the array slice.
+        //
+        // We expect such "straddler characters" to be rare.
+
+        if (offset >= offsetLimit) {  // No bytes? No progress.
+          return state;
+        }
+        int byte1 = (byte) state;
+        // byte1 is never ASCII.
+        if (byte1 < (byte) 0xE0) {
+          // two-byte form
+
+          // Simultaneously checks for illegal trailing-byte in
+          // leading position and overlong 2-byte form.
+          if (byte1 < (byte) 0xC2
+              // byte2 trailing-byte test
+              || UNSAFE.getByte(bytes, offset++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else if (byte1 < (byte) 0xF0) {
+          // three-byte form
+
+          // Get byte2 from saved state or array
+          int byte2 = (byte) ~(state >> 8);
+          if (byte2 == 0) {
+            byte2 = UNSAFE.getByte(bytes, offset++);
+            if (offset >= offsetLimit) {
+              return incompleteStateFor(byte1, byte2);
+            }
+          }
+          if (byte2 > (byte) 0xBF
+              // overlong? 5 most significant bits must not all be zero
+              || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
+              // illegal surrogate codepoint?
+              || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
+              // byte3 trailing-byte test
+              || UNSAFE.getByte(bytes, offset++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else {
+          // four-byte form
+
+          // Get byte2 and byte3 from saved state or array
+          int byte2 = (byte) ~(state >> 8);
+          int byte3 = 0;
+          if (byte2 == 0) {
+            byte2 = UNSAFE.getByte(bytes, offset++);
+            if (offset >= offsetLimit) {
+              return incompleteStateFor(byte1, byte2);
+            }
+          } else {
+            byte3 = (byte) (state >> 16);
+          }
+          if (byte3 == 0) {
+            byte3 = UNSAFE.getByte(bytes, offset++);
+            if (offset >= offsetLimit) {
+              return incompleteStateFor(byte1, byte2, byte3);
+            }
+          }
+
+          // If we were called with state == MALFORMED, then byte1 is 0xFF,
+          // which never occurs in well-formed UTF-8, and so we will return
+          // MALFORMED again below.
+
+          if (byte2 > (byte) 0xBF
+              // Check that 1 <= plane <= 16.  Tricky optimized form of:
+              // if (byte1 > (byte) 0xF4 ||
+              //     byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 ||
+              //     byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
+              || (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0
+              // byte3 trailing-byte test
+              || byte3 > (byte) 0xBF
+              // byte4 trailing-byte test
+              || UNSAFE.getByte(bytes, offset++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        }
+      }
+
+      return partialIsValidUtf8(bytes, offset, (int) (offsetLimit - offset));
+    }
+
+    @Override
+    int partialIsValidUtf8Direct(
+        final int state, ByteBuffer buffer, final int index, final int limit) {
+      if ((index | limit | buffer.limit() - limit) < 0) {
+        throw new ArrayIndexOutOfBoundsException(
+            String.format("buffer limit=%d, index=%d, limit=%d", buffer.limit(), index, limit));
+      }
+      long address = addressOffset(buffer) + index;
+      final long addressLimit = address + (limit - index);
+      if (state != COMPLETE) {
+        // The previous decoding operation was incomplete (or malformed).
+        // We look for a well-formed sequence consisting of bytes from
+        // the previous decoding operation (stored in state) together
+        // with bytes from the array slice.
+        //
+        // We expect such "straddler characters" to be rare.
+
+        if (address >= addressLimit) { // No bytes? No progress.
+          return state;
+        }
+
+        final int byte1 = (byte) state;
+        // byte1 is never ASCII.
+        if (byte1 < (byte) 0xE0) {
+          // two-byte form
+
+          // Simultaneously checks for illegal trailing-byte in
+          // leading position and overlong 2-byte form.
+          if (byte1 < (byte) 0xC2
+              // byte2 trailing-byte test
+              || UNSAFE.getByte(address++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else if (byte1 < (byte) 0xF0) {
+          // three-byte form
+
+          // Get byte2 from saved state or array
+          int byte2 = (byte) ~(state >> 8);
+          if (byte2 == 0) {
+            byte2 = UNSAFE.getByte(address++);
+            if (address >= addressLimit) {
+              return incompleteStateFor(byte1, byte2);
+            }
+          }
+          if (byte2 > (byte) 0xBF
+              // overlong? 5 most significant bits must not all be zero
+              || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
+              // illegal surrogate codepoint?
+              || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
+              // byte3 trailing-byte test
+              || UNSAFE.getByte(address++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else {
+          // four-byte form
+
+          // Get byte2 and byte3 from saved state or array
+          int byte2 = (byte) ~(state >> 8);
+          int byte3 = 0;
+          if (byte2 == 0) {
+            byte2 = UNSAFE.getByte(address++);
+            if (address >= addressLimit) {
+              return incompleteStateFor(byte1, byte2);
+            }
+          } else {
+            byte3 = (byte) (state >> 16);
+          }
+          if (byte3 == 0) {
+            byte3 = UNSAFE.getByte(address++);
+            if (address >= addressLimit) {
+              return incompleteStateFor(byte1, byte2, byte3);
+            }
+          }
+
+          // If we were called with state == MALFORMED, then byte1 is 0xFF,
+          // which never occurs in well-formed UTF-8, and so we will return
+          // MALFORMED again below.
+
+          if (byte2 > (byte) 0xBF
+              // Check that 1 <= plane <= 16.  Tricky optimized form of:
+              // if (byte1 > (byte) 0xF4 ||
+              //     byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 ||
+              //     byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
+              || (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0
+              // byte3 trailing-byte test
+              || byte3 > (byte) 0xBF
+              // byte4 trailing-byte test
+              || UNSAFE.getByte(address++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        }
+      }
+
+      return partialIsValidUtf8(address, (int) (addressLimit - address));
+    }
+
+    @Override
+    int encodeUtf8(final CharSequence in, final byte[] out, final int offset, final int length) {
+      long outIx = ARRAY_BASE_OFFSET + offset;
+      final long outLimit = outIx + length;
+      final int inLimit = in.length();
+      if (inLimit > length || out.length - length < offset) {
+        // Not even enough room for an ASCII-encoded string.
+        throw new ArrayIndexOutOfBoundsException(
+            "Failed writing " + in.charAt(inLimit - 1) + " at index " + (offset + length));
+      }
+
+      // Designed to take advantage of
+      // https://wikis.oracle.com/display/HotSpotInternals/RangeCheckElimination
+      int inIx = 0;
+      for (char c; inIx < inLimit && (c = in.charAt(inIx)) < 0x80; ++inIx) {
+        UNSAFE.putByte(out, outIx++, (byte) c);
+      }
+      if (inIx == inLimit) {
+        // We're done, it was ASCII encoded.
+        return (int) (outIx - ARRAY_BASE_OFFSET);
+      }
+
+      for (char c; inIx < inLimit; ++inIx) {
+        c = in.charAt(inIx);
+        if (c < 0x80 && outIx < outLimit) {
+          UNSAFE.putByte(out, outIx++, (byte) c);
+        } else if (c < 0x800 && outIx <= outLimit - 2L) { // 11 bits, two UTF-8 bytes
+          UNSAFE.putByte(out, outIx++, (byte) ((0xF << 6) | (c >>> 6)));
+          UNSAFE.putByte(out, outIx++, (byte) (0x80 | (0x3F & c)));
+        } else if ((c < MIN_SURROGATE || MAX_SURROGATE < c) && outIx <= outLimit - 3L) {
+          // Maximum single-char code point is 0xFFFF, 16 bits, three UTF-8 bytes
+          UNSAFE.putByte(out, outIx++, (byte) ((0xF << 5) | (c >>> 12)));
+          UNSAFE.putByte(out, outIx++, (byte) (0x80 | (0x3F & (c >>> 6))));
+          UNSAFE.putByte(out, outIx++, (byte) (0x80 | (0x3F & c)));
+        } else if (outIx <= outLimit - 4L) {
+          // Minimum code point represented by a surrogate pair is 0x10000, 17 bits, four UTF-8
+          // bytes
+          final char low;
+          if (inIx + 1 == inLimit || !isSurrogatePair(c, (low = in.charAt(++inIx)))) {
+            throw new UnpairedSurrogateException((inIx - 1), inLimit);
+          }
+          int codePoint = toCodePoint(c, low);
+          UNSAFE.putByte(out, outIx++, (byte) ((0xF << 4) | (codePoint >>> 18)));
+          UNSAFE.putByte(out, outIx++, (byte) (0x80 | (0x3F & (codePoint >>> 12))));
+          UNSAFE.putByte(out, outIx++, (byte) (0x80 | (0x3F & (codePoint >>> 6))));
+          UNSAFE.putByte(out, outIx++, (byte) (0x80 | (0x3F & codePoint)));
+        } else {
+          if ((MIN_SURROGATE <= c && c <= MAX_SURROGATE)
+              && (inIx + 1 == inLimit || !isSurrogatePair(c, in.charAt(inIx + 1)))) {
+            // We are surrogates and we're not a surrogate pair.
+            throw new UnpairedSurrogateException(inIx, inLimit);
+          }
+          // Not enough space in the output buffer.
+          throw new ArrayIndexOutOfBoundsException("Failed writing " + c + " at index " + outIx);
+        }
+      }
+
+      // All bytes have been encoded.
+      return (int) (outIx - ARRAY_BASE_OFFSET);
+    }
+
+    @Override
+    void encodeUtf8Direct(CharSequence in, ByteBuffer out) {
+      final long address = addressOffset(out);
+      long outIx = address + out.position();
+      final long outLimit = address + out.limit();
+      final int inLimit = in.length();
+      if (inLimit > outLimit - outIx) {
+        // Not even enough room for an ASCII-encoded string.
+        throw new ArrayIndexOutOfBoundsException(
+            "Failed writing " + in.charAt(inLimit - 1) + " at index " + out.limit());
+      }
+
+      // Designed to take advantage of
+      // https://wikis.oracle.com/display/HotSpotInternals/RangeCheckElimination
+      int inIx = 0;
+      for (char c; inIx < inLimit && (c = in.charAt(inIx)) < 0x80; ++inIx) {
+        UNSAFE.putByte(outIx++, (byte) c);
+      }
+      if (inIx == inLimit) {
+        // We're done, it was ASCII encoded.
+        out.position((int) (outIx - address));
+        return;
+      }
+
+      for (char c; inIx < inLimit; ++inIx) {
+        c = in.charAt(inIx);
+        if (c < 0x80 && outIx < outLimit) {
+          UNSAFE.putByte(outIx++, (byte) c);
+        } else if (c < 0x800 && outIx <= outLimit - 2L) { // 11 bits, two UTF-8 bytes
+          UNSAFE.putByte(outIx++, (byte) ((0xF << 6) | (c >>> 6)));
+          UNSAFE.putByte(outIx++, (byte) (0x80 | (0x3F & c)));
+        } else if ((c < MIN_SURROGATE || MAX_SURROGATE < c) && outIx <= outLimit - 3L) {
+          // Maximum single-char code point is 0xFFFF, 16 bits, three UTF-8 bytes
+          UNSAFE.putByte(outIx++, (byte) ((0xF << 5) | (c >>> 12)));
+          UNSAFE.putByte(outIx++, (byte) (0x80 | (0x3F & (c >>> 6))));
+          UNSAFE.putByte(outIx++, (byte) (0x80 | (0x3F & c)));
+        } else if (outIx <= outLimit - 4L) {
+          // Minimum code point represented by a surrogate pair is 0x10000, 17 bits, four UTF-8
+          // bytes
+          final char low;
+          if (inIx + 1 == inLimit || !isSurrogatePair(c, (low = in.charAt(++inIx)))) {
+            throw new UnpairedSurrogateException((inIx - 1), inLimit);
+          }
+          int codePoint = toCodePoint(c, low);
+          UNSAFE.putByte(outIx++, (byte) ((0xF << 4) | (codePoint >>> 18)));
+          UNSAFE.putByte(outIx++, (byte) (0x80 | (0x3F & (codePoint >>> 12))));
+          UNSAFE.putByte(outIx++, (byte) (0x80 | (0x3F & (codePoint >>> 6))));
+          UNSAFE.putByte(outIx++, (byte) (0x80 | (0x3F & codePoint)));
+        } else {
+          if ((MIN_SURROGATE <= c && c <= MAX_SURROGATE)
+              && (inIx + 1 == inLimit || !isSurrogatePair(c, in.charAt(inIx + 1)))) {
+            // We are surrogates and we're not a surrogate pair.
+            throw new UnpairedSurrogateException(inIx, inLimit);
+          }
+          // Not enough space in the output buffer.
+          throw new ArrayIndexOutOfBoundsException("Failed writing " + c + " at index " + outIx);
+        }
+      }
+
+      // All bytes have been encoded.
+      out.position((int) (outIx - address));
+    }
+
+    /**
+     * Counts (approximately) the number of consecutive ASCII characters starting from the given
+     * position, using the most efficient method available to the platform.
+     *
+     * @param bytes the array containing the character sequence
+     * @param offset the offset position of the index (same as index + arrayBaseOffset)
+     * @param maxChars the maximum number of characters to count
+     * @return the number of ASCII characters found. The stopping position will be at or
+     * before the first non-ASCII byte.
+     */
+    private static int unsafeEstimateConsecutiveAscii(
+        byte[] bytes, long offset, final int maxChars) {
+      int remaining = maxChars;
+      if (remaining < UNSAFE_COUNT_ASCII_THRESHOLD) {
+        // Don't bother with small strings.
+        return 0;
+      }
+
+      // Read bytes until 8-byte aligned so that we can read longs in the loop below.
+      // Byte arrays are already either 8 or 16-byte aligned, so we just need to make sure that
+      // the index (relative to the start of the array) is also 8-byte aligned. We do this by
+      // ANDing the index with 7 to determine the number of bytes that need to be read before
+      // we're 8-byte aligned.
+      final int unaligned = (int) offset & 7;
+      for (int j = unaligned; j > 0; j--) {
+        if (UNSAFE.getByte(bytes, offset++) < 0) {
+          return unaligned - j;
+        }
+      }
+
+      // This simple loop stops when we encounter a byte >= 0x80 (i.e. non-ASCII).
+      // To speed things up further, we're reading longs instead of bytes so we use a mask to
+      // determine if any byte in the current long is non-ASCII.
+      remaining -= unaligned;
+      for (; remaining >= 8 && (UNSAFE.getLong(bytes, offset) & ASCII_MASK_LONG) == 0;
+          offset += 8, remaining -= 8) {}
+      return maxChars - remaining;
+    }
+
+    /**
+     * Same as {@link Utf8#estimateConsecutiveAscii(ByteBuffer, int, int)} except that it uses the
+     * most efficient method available to the platform.
+     */
+    private static int unsafeEstimateConsecutiveAscii(long address, final int maxChars) {
+      int remaining = maxChars;
+      if (remaining < UNSAFE_COUNT_ASCII_THRESHOLD) {
+        // Don't bother with small strings.
+        return 0;
+      }
+
+      // Read bytes until 8-byte aligned so that we can read longs in the loop below.
+      // We do this by ANDing the address with 7 to determine the number of bytes that need to
+      // be read before we're 8-byte aligned.
+      final int unaligned = (int) address & 7;
+      for (int j = unaligned; j > 0; j--) {
+        if (UNSAFE.getByte(address++) < 0) {
+          return unaligned - j;
+        }
+      }
+
+      // This simple loop stops when we encounter a byte >= 0x80 (i.e. non-ASCII).
+      // To speed things up further, we're reading longs instead of bytes so we use a mask to
+      // determine if any byte in the current long is non-ASCII.
+      remaining -= unaligned;
+      for (; remaining >= 8 && (UNSAFE.getLong(address) & ASCII_MASK_LONG) == 0;
+          address += 8, remaining -= 8) {}
+      return maxChars - remaining;
+    }
+
+    private static int partialIsValidUtf8(final byte[] bytes, long offset, int remaining) {
+      // Skip past ASCII characters as quickly as possible. 
+      final int skipped = unsafeEstimateConsecutiveAscii(bytes, offset, remaining);
+      remaining -= skipped;
+      offset += skipped;
+
+      for (;;) {
+        // Optimize for interior runs of ASCII bytes.
+        // TODO(nathanmittler): Consider checking 8 bytes at a time after some threshold?
+        // Maybe after seeing a few in a row that are ASCII, go back to fast mode?
+        int byte1 = 0;
+        for (; remaining > 0 && (byte1 = UNSAFE.getByte(bytes, offset++)) >= 0; --remaining) {
+        }
+        if (remaining == 0) {
+          return COMPLETE;
+        }
+        remaining--;
+
+        // If we're here byte1 is not ASCII. Only need to handle 2-4 byte forms.
+        if (byte1 < (byte) 0xE0) {
+          // Two-byte form (110xxxxx 10xxxxxx)
+          if (remaining == 0) {
+            // Incomplete sequence
+            return byte1;
+          }
+          remaining--;
+
+          // Simultaneously checks for illegal trailing-byte in
+          // leading position and overlong 2-byte form.
+          if (byte1 < (byte) 0xC2
+              || UNSAFE.getByte(bytes, offset++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else if (byte1 < (byte) 0xF0) {
+          // Three-byte form (1110xxxx 10xxxxxx 10xxxxxx)
+          if (remaining < 2) {
+            // Incomplete sequence
+            return unsafeIncompleteStateFor(bytes, byte1, offset, remaining);
+          }
+          remaining -= 2;
+
+          final int byte2;
+          if ((byte2 = UNSAFE.getByte(bytes, offset++)) > (byte) 0xBF
+              // overlong? 5 most significant bits must not all be zero
+              || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
+              // check for illegal surrogate codepoints
+              || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
+              // byte3 trailing-byte test
+              || UNSAFE.getByte(bytes, offset++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else {
+          // Four-byte form (1110xxxx 10xxxxxx 10xxxxxx 10xxxxxx)
+          if (remaining < 3) {
+            // Incomplete sequence
+            return unsafeIncompleteStateFor(bytes, byte1, offset, remaining);
+          }
+          remaining -= 3;
+
+          final int byte2;
+          if ((byte2 = UNSAFE.getByte(bytes, offset++)) > (byte) 0xBF
+              // Check that 1 <= plane <= 16.  Tricky optimized form of:
+              // if (byte1 > (byte) 0xF4 ||
+              //     byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 ||
+              //     byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
+              || (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0
+              // byte3 trailing-byte test
+              || UNSAFE.getByte(bytes, offset++) > (byte) 0xBF
+              // byte4 trailing-byte test
+              || UNSAFE.getByte(bytes, offset++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        }
+      }
+    }
+
+    private static int partialIsValidUtf8(long address, int remaining) {
+      // Skip past ASCII characters as quickly as possible.
+      final int skipped = unsafeEstimateConsecutiveAscii(address, remaining);
+      address += skipped;
+      remaining -= skipped;
+
+      for (;;) {
+        // Optimize for interior runs of ASCII bytes.
+        // TODO(nathanmittler): Consider checking 8 bytes at a time after some threshold?
+        // Maybe after seeing a few in a row that are ASCII, go back to fast mode?
+        int byte1 = 0;
+        for (; remaining > 0 && (byte1 = UNSAFE.getByte(address++)) >= 0; --remaining) {
+        }
+        if (remaining == 0) {
+          return COMPLETE;
+        }
+        remaining--;
+
+        if (byte1 < (byte) 0xE0) {
+          // Two-byte form
+
+          if (remaining == 0) {
+            // Incomplete sequence
+            return byte1;
+          }
+          remaining--;
+
+          // Simultaneously checks for illegal trailing-byte in
+          // leading position and overlong 2-byte form.
+          if (byte1 < (byte) 0xC2 || UNSAFE.getByte(address++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else if (byte1 < (byte) 0xF0) {
+          // Three-byte form
+
+          if (remaining < 2) {
+            // Incomplete sequence
+            return unsafeIncompleteStateFor(address, byte1, remaining);
+          }
+          remaining -= 2;
+
+          final byte byte2 = UNSAFE.getByte(address++);
+          if (byte2 > (byte) 0xBF
+              // overlong? 5 most significant bits must not all be zero
+              || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
+              // check for illegal surrogate codepoints
+              || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
+              // byte3 trailing-byte test
+              || UNSAFE.getByte(address++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        } else {
+          // Four-byte form
+
+          if (remaining < 3) {
+            // Incomplete sequence
+            return unsafeIncompleteStateFor(address, byte1, remaining);
+          }
+          remaining -= 3;
+
+          final byte byte2 = UNSAFE.getByte(address++);
+          if (byte2 > (byte) 0xBF
+              // Check that 1 <= plane <= 16.  Tricky optimized form of:
+              // if (byte1 > (byte) 0xF4 ||
+              //     byte1 == (byte) 0xF0 && byte2 < (byte) 0x90 ||
+              //     byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
+              || (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0
+              // byte3 trailing-byte test
+              || UNSAFE.getByte(address++) > (byte) 0xBF
+              // byte4 trailing-byte test
+              || UNSAFE.getByte(address++) > (byte) 0xBF) {
+            return MALFORMED;
+          }
+        }
+      }
+    }
+
+    private static int unsafeIncompleteStateFor(byte[] bytes, int byte1, long offset,
+        int remaining) {
+      switch (remaining) {
+        case 0: {
+          return incompleteStateFor(byte1);
+        }
+        case 1: {
+          return incompleteStateFor(byte1, UNSAFE.getByte(bytes, offset));
+        }
+        case 2: {
+          return incompleteStateFor(byte1, UNSAFE.getByte(bytes, offset),
+              UNSAFE.getByte(bytes, offset + 1));
+        }
+        default: {
+          throw new AssertionError();
+        }
+      }
+    }
+
+    private static int unsafeIncompleteStateFor(long address, final int byte1, int remaining) {
+      switch (remaining) {
+        case 0: {
+          return incompleteStateFor(byte1);
+        }
+        case 1: {
+          return incompleteStateFor(byte1, UNSAFE.getByte(address));
+        }
+        case 2: {
+          return incompleteStateFor(byte1, UNSAFE.getByte(address), UNSAFE.getByte(address + 1));
+        }
+        default: {
+          throw new AssertionError();
+        }
+      }
+    }
+
+    /**
+     * Gets the field with the given name within the class, or {@code null} if not found. If
+     * found, the field is made accessible.
+     */
+    private static Field field(Class<?> clazz, String fieldName) {
+      Field field;
+      try {
+        field = clazz.getDeclaredField(fieldName);
+        field.setAccessible(true);
+      } catch (Throwable t) {
+        // Failed to access the fields.
+        field = null;
+      }
+      logger.log(Level.FINEST, "{0}.{1}: {2}",
+          new Object[] {clazz.getName(), fieldName, (field != null ? "available" : "unavailable")});
+      return field;
+    }
+
+    /**
+     * Returns the offset of the provided field, or {@code -1} if {@code sun.misc.Unsafe} is not
+     * available.
+     */
+    private static long fieldOffset(Field field) {
+      return field == null || UNSAFE == null ? -1 : UNSAFE.objectFieldOffset(field);
+    }
+
+    /**
+     * Get the base offset for byte arrays, or {@code -1} if {@code sun.misc.Unsafe} is not
+     * available.
+     */
+    private static <T> int byteArrayBaseOffset() {
+      return UNSAFE == null ? -1 : UNSAFE.arrayBaseOffset(byte[].class);
+    }
+
+    /**
+     * Gets the offset of the {@code address} field of the given direct {@link ByteBuffer}.
+     */
+    private static long addressOffset(ByteBuffer buffer) {
+      return UNSAFE.getLong(buffer, BUFFER_ADDRESS_OFFSET);
+    }
+
+    /**
+     * 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;
+
+            // Check that this platform supports all of the required unsafe methods.
+            checkRequiredMethods(k);
+
+            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;
+    }
+
+    /**
+     * Verifies that all required methods of {@code sun.misc.Unsafe} are available on this platform.
+     */
+    private static void checkRequiredMethods(Class<sun.misc.Unsafe> clazz)
+        throws NoSuchMethodException, SecurityException {
+      // Needed for Unsafe byte[] access
+      clazz.getMethod("arrayBaseOffset", Class.class);
+      clazz.getMethod("getByte", Object.class, long.class);
+      clazz.getMethod("putByte", Object.class, long.class, byte.class);
+      clazz.getMethod("getLong", Object.class, long.class);
+
+      // Needed for Unsafe Direct ByteBuffer access
+      clazz.getMethod("objectFieldOffset", Field.class);
+      clazz.getMethod("getByte", long.class);
+      clazz.getMethod("getLong", Object.class, long.class);
+      clazz.getMethod("putByte", long.class, byte.class);
+      clazz.getMethod("getLong", long.class);
+    }
+  }
+
+  private Utf8() {}
 }
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 d964ef59..1e57b647 100644
--- a/java/core/src/test/java/com/google/protobuf/AbstractMessageTest.java
+++ b/java/core/src/test/java/com/google/protobuf/AbstractMessageTest.java
@@ -40,7 +40,6 @@ import protobuf_unittest.UnittestProto.TestPackedTypes;
 import protobuf_unittest.UnittestProto.TestRequired;
 import protobuf_unittest.UnittestProto.TestRequiredForeign;
 import protobuf_unittest.UnittestProto.TestUnpackedTypes;
-
 import junit.framework.TestCase;
 
 import java.util.Map;
diff --git a/java/core/src/test/java/com/google/protobuf/AnyTest.java b/java/core/src/test/java/com/google/protobuf/AnyTest.java
index e169f69d..cf91ed91 100644
--- a/java/core/src/test/java/com/google/protobuf/AnyTest.java
+++ b/java/core/src/test/java/com/google/protobuf/AnyTest.java
@@ -75,6 +75,51 @@ public class AnyTest extends TestCase {
     }
   }
 
+  public void testCustomTypeUrls() throws Exception {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    TestUtil.setAllFields(builder);
+    TestAllTypes message = builder.build();
+
+    TestAny container = TestAny.newBuilder()
+        .setValue(Any.pack(message, "xxx.com")).build();
+
+    assertEquals(
+        "xxx.com/" + TestAllTypes.getDescriptor().getFullName(),
+        container.getValue().getTypeUrl());
+
+    assertTrue(container.getValue().is(TestAllTypes.class));
+    assertFalse(container.getValue().is(TestAny.class));
+
+    TestAllTypes result = container.getValue().unpack(TestAllTypes.class);
+    TestUtil.assertAllFieldsSet(result);
+
+    container = TestAny.newBuilder()
+        .setValue(Any.pack(message, "yyy.com/")).build();
+
+    assertEquals(
+        "yyy.com/" + TestAllTypes.getDescriptor().getFullName(),
+        container.getValue().getTypeUrl());
+
+    assertTrue(container.getValue().is(TestAllTypes.class));
+    assertFalse(container.getValue().is(TestAny.class));
+
+    result = container.getValue().unpack(TestAllTypes.class);
+    TestUtil.assertAllFieldsSet(result);
+
+    container = TestAny.newBuilder()
+        .setValue(Any.pack(message, "")).build();
+
+    assertEquals(
+        "/" + TestAllTypes.getDescriptor().getFullName(),
+        container.getValue().getTypeUrl());
+
+    assertTrue(container.getValue().is(TestAllTypes.class));
+    assertFalse(container.getValue().is(TestAny.class));
+
+    result = container.getValue().unpack(TestAllTypes.class);
+    TestUtil.assertAllFieldsSet(result);
+  }
+
   public void testCachedUnpackResult() throws Exception {
     TestAllTypes.Builder builder = TestAllTypes.newBuilder();
     TestUtil.setAllFields(builder);
diff --git a/java/core/src/test/java/com/google/protobuf/BoundedByteStringTest.java b/java/core/src/test/java/com/google/protobuf/BoundedByteStringTest.java
index 7a8a0a5e..db10ee74 100644
--- a/java/core/src/test/java/com/google/protobuf/BoundedByteStringTest.java
+++ b/java/core/src/test/java/com/google/protobuf/BoundedByteStringTest.java
@@ -37,7 +37,6 @@ import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.io.UnsupportedEncodingException;
 
-
 /**
  * This class tests {@link BoundedByteString}, which extends {@link LiteralByteString},
  * by inheriting the tests from {@link LiteralByteStringTest}.  The only method which
diff --git a/java/core/src/test/java/com/google/protobuf/ByteBufferWriterTest.java b/java/core/src/test/java/com/google/protobuf/ByteBufferWriterTest.java
new file mode 100644
index 00000000..cbe742e5
--- /dev/null
+++ b/java/core/src/test/java/com/google/protobuf/ByteBufferWriterTest.java
@@ -0,0 +1,81 @@
+// 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 junit.framework.TestCase;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.Random;
+
+/**
+ * Tests for {@link ByteBufferWriter}.
+ */
+public class ByteBufferWriterTest extends TestCase {
+
+  public void testHeapBuffer() throws IOException {
+    // Test a small and large buffer.
+    testWrite(ByteBuffer.allocate(100));
+    testWrite(ByteBuffer.allocate(1024 * 100));
+  }
+
+  public void testDirectBuffer() throws IOException {
+    // Test a small and large buffer.
+    testWrite(ByteBuffer.allocateDirect(100));
+    testWrite(ByteBuffer.allocateDirect(1024 * 100));
+  }
+
+  private void testWrite(ByteBuffer buffer) throws IOException {
+    fillRandom(buffer);
+    ByteArrayOutputStream os = new ByteArrayOutputStream(buffer.remaining());
+    ByteBufferWriter.write(buffer, os);
+    assertEquals(0, buffer.position());
+    assertTrue(Arrays.equals(toArray(buffer), os.toByteArray()));
+  }
+
+  private void fillRandom(ByteBuffer buf) {
+    byte[] bytes = new byte[buf.remaining()];
+    new Random().nextBytes(bytes);
+    buf.put(bytes);
+    buf.flip();
+    return;
+  }
+
+  private byte[] toArray(ByteBuffer buf) {
+    int originalPosition = buf.position();
+    byte[] bytes = new byte[buf.remaining()];
+    buf.get(bytes);
+    buf.position(originalPosition);
+    return bytes;
+  }
+}
diff --git a/java/core/src/test/java/com/google/protobuf/ByteStringTest.java b/java/core/src/test/java/com/google/protobuf/ByteStringTest.java
index 5267c160..ad9f266e 100644
--- a/java/core/src/test/java/com/google/protobuf/ByteStringTest.java
+++ b/java/core/src/test/java/com/google/protobuf/ByteStringTest.java
@@ -39,6 +39,7 @@ import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.lang.reflect.Field;
 import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
@@ -757,4 +758,17 @@ public class ByteStringTest extends TestCase {
     assertEquals((byte) 2, result[dataSize - dataSize / 2]);
     assertEquals((byte) 2, result[dataSize - 1]);
   }
+  
+  /**
+   * Tests ByteString uses Arrays based byte copier when running under Hotstop VM.
+   */
+  public void testByteArrayCopier() throws Exception {
+    Field field = ByteString.class.getDeclaredField("byteArrayCopier");
+    field.setAccessible(true);
+    Object byteArrayCopier = field.get(null);
+    assertNotNull(byteArrayCopier);
+    assertTrue(
+        byteArrayCopier.toString(),
+        byteArrayCopier.getClass().getSimpleName().endsWith("ArraysByteArrayCopier"));
+  }
 }
diff --git a/java/core/src/test/java/com/google/protobuf/CheckUtf8Test.java b/java/core/src/test/java/com/google/protobuf/CheckUtf8Test.java
index 3d6381c9..cc65d19a 100644
--- a/java/core/src/test/java/com/google/protobuf/CheckUtf8Test.java
+++ b/java/core/src/test/java/com/google/protobuf/CheckUtf8Test.java
@@ -34,6 +34,7 @@ import proto2_test_check_utf8.TestCheckUtf8.BytesWrapper;
 import proto2_test_check_utf8.TestCheckUtf8.StringWrapper;
 import proto2_test_check_utf8_size.TestCheckUtf8Size.BytesWrapperSize;
 import proto2_test_check_utf8_size.TestCheckUtf8Size.StringWrapperSize;
+
 import junit.framework.TestCase;
 
 /**
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 18d8142c..a1d6f1be 100644
--- a/java/core/src/test/java/com/google/protobuf/CodedInputStreamTest.java
+++ b/java/core/src/test/java/com/google/protobuf/CodedInputStreamTest.java
@@ -547,6 +547,56 @@ public class CodedInputStreamTest extends TestCase {
     }
   }
 
+  public void testReadString() throws Exception {
+    String lorem = "Lorem ipsum dolor sit amet ";
+    StringBuilder builder = new StringBuilder();
+    for (int i = 0; i < 4096; i += lorem.length()) {
+      builder.append(lorem);
+    }
+    lorem = builder.toString().substring(0, 4096);
+    byte[] bytes = lorem.getBytes("UTF-8");
+    ByteString.Output rawOutput = ByteString.newOutput();
+    CodedOutputStream output = CodedOutputStream.newInstance(rawOutput, bytes.length);
+
+    int tag = WireFormat.makeTag(1, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+    output.writeRawVarint32(tag);
+    output.writeRawVarint32(bytes.length);
+    output.writeRawBytes(bytes);
+    output.flush();
+
+    CodedInputStream input =
+        CodedInputStream.newInstance(
+            new ByteArrayInputStream(rawOutput.toByteString().toByteArray()));
+    assertEquals(tag, input.readTag());
+    String text = input.readString();
+    assertEquals(lorem, text);
+  }
+
+  public void testReadStringRequireUtf8() throws Exception {
+    String lorem = "Lorem ipsum dolor sit amet ";
+    StringBuilder builder = new StringBuilder();
+    for (int i = 0; i < 4096; i += lorem.length()) {
+      builder.append(lorem);
+    }
+    lorem = builder.toString().substring(0, 4096);
+    byte[] bytes = lorem.getBytes("UTF-8");
+    ByteString.Output rawOutput = ByteString.newOutput();
+    CodedOutputStream output = CodedOutputStream.newInstance(rawOutput, bytes.length);
+
+    int tag = WireFormat.makeTag(1, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+    output.writeRawVarint32(tag);
+    output.writeRawVarint32(bytes.length);
+    output.writeRawBytes(bytes);
+    output.flush();
+
+    CodedInputStream input =
+        CodedInputStream.newInstance(
+            new ByteArrayInputStream(rawOutput.toByteString().toByteArray()));
+    assertEquals(tag, input.readTag());
+    String text = input.readStringRequireUtf8();
+    assertEquals(lorem, text);
+  }
+
   /**
    * Tests that if we readString invalid UTF-8 bytes, no exception
    * is thrown.  Instead, the invalid bytes are replaced with the Unicode
diff --git a/java/core/src/test/java/com/google/protobuf/DeprecatedFieldTest.java b/java/core/src/test/java/com/google/protobuf/DeprecatedFieldTest.java
index e7905f79..ce85ae2e 100644
--- a/java/core/src/test/java/com/google/protobuf/DeprecatedFieldTest.java
+++ b/java/core/src/test/java/com/google/protobuf/DeprecatedFieldTest.java
@@ -36,6 +36,7 @@ import junit.framework.TestCase;
 
 import java.lang.reflect.AnnotatedElement;
 import java.lang.reflect.Method;
+
 /**
  * Test field deprecation
  * 
diff --git a/java/core/src/test/java/com/google/protobuf/DescriptorsTest.java b/java/core/src/test/java/com/google/protobuf/DescriptorsTest.java
index 82ff34af..ef89b389 100644
--- a/java/core/src/test/java/com/google/protobuf/DescriptorsTest.java
+++ b/java/core/src/test/java/com/google/protobuf/DescriptorsTest.java
@@ -59,7 +59,6 @@ import protobuf_unittest.UnittestProto.TestMultipleExtensionRanges;
 import protobuf_unittest.UnittestProto.TestRequired;
 import protobuf_unittest.UnittestProto.TestReservedFields;
 import protobuf_unittest.UnittestProto.TestService;
-
 import junit.framework.TestCase;
 
 import java.util.Arrays;
@@ -573,6 +572,42 @@ public class DescriptorsTest extends TestCase {
     }
   }
 
+  public void testUnknownFieldsDenied() throws Exception {
+    FileDescriptorProto fooProto = FileDescriptorProto.newBuilder()
+        .setName("foo.proto")
+        .addMessageType(DescriptorProto.newBuilder()
+            .setName("Foo")
+            .addField(FieldDescriptorProto.newBuilder()
+                .setLabel(FieldDescriptorProto.Label.LABEL_OPTIONAL)
+                .setTypeName("Bar")
+                .setName("bar")
+                .setNumber(1)))
+        .build();
+
+    try {
+      Descriptors.FileDescriptor.buildFrom(fooProto, new FileDescriptor[0]);
+      fail("DescriptorValidationException expected");
+    } catch (DescriptorValidationException e) {
+      assertTrue(e.getMessage().indexOf("Bar") != -1);
+      assertTrue(e.getMessage().indexOf("is not defined") != -1);
+    }
+  }
+
+  public void testUnknownFieldsAllowed() throws Exception {
+    FileDescriptorProto fooProto = FileDescriptorProto.newBuilder()
+        .setName("foo.proto")
+        .addDependency("bar.proto")
+        .addMessageType(DescriptorProto.newBuilder()
+            .setName("Foo")
+            .addField(FieldDescriptorProto.newBuilder()
+                .setLabel(FieldDescriptorProto.Label.LABEL_OPTIONAL)
+                .setTypeName("Bar")
+                .setName("bar")
+                .setNumber(1)))
+        .build();
+    Descriptors.FileDescriptor.buildFrom(fooProto, new FileDescriptor[0], true);
+  }
+
   public void testHiddenDependency() throws Exception {
     FileDescriptorProto barProto = FileDescriptorProto.newBuilder()
         .setName("bar.proto")
diff --git a/java/core/src/test/java/com/google/protobuf/DynamicMessageTest.java b/java/core/src/test/java/com/google/protobuf/DynamicMessageTest.java
index 55144e7c..8f3a74c1 100644
--- a/java/core/src/test/java/com/google/protobuf/DynamicMessageTest.java
+++ b/java/core/src/test/java/com/google/protobuf/DynamicMessageTest.java
@@ -33,13 +33,13 @@ package com.google.protobuf;
 import com.google.protobuf.Descriptors.EnumDescriptor;
 import com.google.protobuf.Descriptors.FieldDescriptor;
 import com.google.protobuf.Descriptors.OneofDescriptor;
-
 import protobuf_unittest.UnittestProto.TestAllExtensions;
 import protobuf_unittest.UnittestProto.TestAllTypes;
 import protobuf_unittest.UnittestProto.TestEmptyMessage;
 import protobuf_unittest.UnittestProto.TestPackedTypes;
 
 import junit.framework.TestCase;
+
 import java.util.Arrays;
 
 /**
diff --git a/java/core/src/test/java/com/google/protobuf/EnumTest.java b/java/core/src/test/java/com/google/protobuf/EnumTest.java
new file mode 100644
index 00000000..14c7406b
--- /dev/null
+++ b/java/core/src/test/java/com/google/protobuf/EnumTest.java
@@ -0,0 +1,76 @@
+// 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 com.google.protobuf.UnittestLite.ForeignEnumLite;
+import com.google.protobuf.UnittestLite.TestAllTypesLite;
+import protobuf_unittest.UnittestProto.ForeignEnum;
+import protobuf_unittest.UnittestProto.TestAllTypes;
+
+import junit.framework.TestCase;
+
+public class EnumTest extends TestCase {
+  
+  public void testForNumber() {
+    ForeignEnum e = ForeignEnum.forNumber(ForeignEnum.FOREIGN_BAR.getNumber());
+    assertEquals(ForeignEnum.FOREIGN_BAR, e);
+
+    e = ForeignEnum.forNumber(1000);
+    assertEquals(null, e);
+  }
+  
+  public void testForNumber_oneof() {
+    TestAllTypes.OneofFieldCase e = TestAllTypes.OneofFieldCase.forNumber(
+        TestAllTypes.OneofFieldCase.ONEOF_NESTED_MESSAGE.getNumber());
+    assertEquals(TestAllTypes.OneofFieldCase.ONEOF_NESTED_MESSAGE, e);
+
+    e = TestAllTypes.OneofFieldCase.forNumber(1000);
+    assertEquals(null, e);
+  }
+  
+  public void testForNumberLite() {
+    ForeignEnumLite e = ForeignEnumLite.forNumber(ForeignEnumLite.FOREIGN_LITE_BAR.getNumber());
+    assertEquals(ForeignEnumLite.FOREIGN_LITE_BAR, e);
+
+    e = ForeignEnumLite.forNumber(1000);
+    assertEquals(null, e);
+  }
+  
+  public void testForNumberLite_oneof() {
+    TestAllTypesLite.OneofFieldCase e = TestAllTypesLite.OneofFieldCase.forNumber(
+        TestAllTypesLite.OneofFieldCase.ONEOF_NESTED_MESSAGE.getNumber());
+    assertEquals(TestAllTypesLite.OneofFieldCase.ONEOF_NESTED_MESSAGE, e);
+
+    e = TestAllTypesLite.OneofFieldCase.forNumber(1000);
+    assertEquals(null, e);
+  }
+}
+
diff --git a/java/core/src/test/java/com/google/protobuf/FieldPresenceTest.java b/java/core/src/test/java/com/google/protobuf/FieldPresenceTest.java
index eaeec0b8..304cec4f 100644
--- a/java/core/src/test/java/com/google/protobuf/FieldPresenceTest.java
+++ b/java/core/src/test/java/com/google/protobuf/FieldPresenceTest.java
@@ -44,9 +44,9 @@ import junit.framework.TestCase;
  * non-message fields.
  */
 public class FieldPresenceTest extends TestCase {
-  private static boolean hasMethod(Class clazz, String name) {
+  private static boolean hasMethod(Class<?> clazz, String name) {
     try {
-      if (clazz.getMethod(name, new Class[]{}) != null) {
+      if (clazz.getMethod(name) != null) {
         return true;
       } else {
         return false;
@@ -56,90 +56,90 @@ public class FieldPresenceTest extends TestCase {
     }
   }
 
-  private static boolean isHasMethodRemoved(
-      Class classWithFieldPresence,
-      Class classWithoutFieldPresence,
+  private static void assertHasMethodRemoved(
+      Class<?> classWithFieldPresence,
+      Class<?> classWithoutFieldPresence,
       String camelName) {
-    return hasMethod(classWithFieldPresence, "get" + camelName)
-        && hasMethod(classWithFieldPresence, "has" + camelName)
-        && hasMethod(classWithoutFieldPresence, "get" + camelName)
-        && !hasMethod(classWithoutFieldPresence, "has" + camelName);
+    assertTrue(hasMethod(classWithFieldPresence, "get" + camelName));
+    assertTrue(hasMethod(classWithFieldPresence, "has" + camelName));
+    assertTrue(hasMethod(classWithoutFieldPresence, "get" + camelName));
+    assertFalse(hasMethod(classWithoutFieldPresence, "has" + camelName));
   }
 
   public void testHasMethod() {
     // Optional non-message fields don't have a hasFoo() method generated.
-    assertTrue(isHasMethodRemoved(
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.class,
         TestAllTypes.class,
-        "OptionalInt32"));
-    assertTrue(isHasMethodRemoved(
+        "OptionalInt32");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.class,
         TestAllTypes.class,
-        "OptionalString"));
-    assertTrue(isHasMethodRemoved(
+        "OptionalString");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.class,
         TestAllTypes.class,
-        "OptionalBytes"));
-    assertTrue(isHasMethodRemoved(
+        "OptionalBytes");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.class,
         TestAllTypes.class,
-        "OptionalNestedEnum"));
+        "OptionalNestedEnum");
 
-    assertTrue(isHasMethodRemoved(
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.Builder.class,
         TestAllTypes.Builder.class,
-        "OptionalInt32"));
-    assertTrue(isHasMethodRemoved(
+        "OptionalInt32");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.Builder.class,
         TestAllTypes.Builder.class,
-        "OptionalString"));
-    assertTrue(isHasMethodRemoved(
+        "OptionalString");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.Builder.class,
         TestAllTypes.Builder.class,
-        "OptionalBytes"));
-    assertTrue(isHasMethodRemoved(
+        "OptionalBytes");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.Builder.class,
         TestAllTypes.Builder.class,
-        "OptionalNestedEnum"));
+        "OptionalNestedEnum");
 
     // message fields still have the hasFoo() method generated.
     assertFalse(TestAllTypes.newBuilder().build().hasOptionalNestedMessage());
     assertFalse(TestAllTypes.newBuilder().hasOptionalNestedMessage());
 
     // oneof fields don't have hasFoo() methods (even for message types).
-    assertTrue(isHasMethodRemoved(
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.class,
         TestAllTypes.class,
-        "OneofUint32"));
-    assertTrue(isHasMethodRemoved(
+        "OneofUint32");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.class,
         TestAllTypes.class,
-        "OneofString"));
-    assertTrue(isHasMethodRemoved(
+        "OneofString");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.class,
         TestAllTypes.class,
-        "OneofBytes"));
-    assertTrue(isHasMethodRemoved(
+        "OneofBytes");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.class,
         TestAllTypes.class,
-        "OneofNestedMessage"));
+        "OneofNestedMessage");
 
-    assertTrue(isHasMethodRemoved(
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.Builder.class,
         TestAllTypes.Builder.class,
-        "OneofUint32"));
-    assertTrue(isHasMethodRemoved(
+        "OneofUint32");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.Builder.class,
         TestAllTypes.Builder.class,
-        "OneofString"));
-    assertTrue(isHasMethodRemoved(
+        "OneofString");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.Builder.class,
         TestAllTypes.Builder.class,
-        "OneofBytes"));
-    assertTrue(isHasMethodRemoved(
+        "OneofBytes");
+    assertHasMethodRemoved(
         UnittestProto.TestAllTypes.Builder.class,
         TestAllTypes.Builder.class,
-        "OneofNestedMessage"));
+        "OneofNestedMessage");
   }
 
   public void testOneofEquals() throws Exception {
@@ -232,24 +232,24 @@ public class FieldPresenceTest extends TestCase {
     assertTrue(message.hasField(optionalNestedEnumField));
     assertEquals(4, message.getAllFields().size());
   }
-  
+
   public void testMessageField() {
     TestAllTypes.Builder builder = TestAllTypes.newBuilder();
     assertFalse(builder.hasOptionalNestedMessage());
     assertFalse(builder.build().hasOptionalNestedMessage());
-    
+
     TestAllTypes.NestedMessage.Builder nestedBuilder =
         builder.getOptionalNestedMessageBuilder();
     assertTrue(builder.hasOptionalNestedMessage());
     assertTrue(builder.build().hasOptionalNestedMessage());
-    
+
     nestedBuilder.setValue(1);
     assertEquals(1, builder.build().getOptionalNestedMessage().getValue());
-    
+
     builder.clearOptionalNestedMessage();
     assertFalse(builder.hasOptionalNestedMessage());
     assertFalse(builder.build().hasOptionalNestedMessage());
-    
+
     // Unlike non-message fields, if we set a message field to its default value (i.e.,
     // default instance), the field should be seen as present.
     builder.setOptionalNestedMessage(TestAllTypes.NestedMessage.getDefaultInstance());
@@ -340,7 +340,7 @@ public class FieldPresenceTest extends TestCase {
     assertTrue(builder.buildPartial().isInitialized());
   }
 
-  
+
   // Test that unknown fields are dropped.
   public void testUnknownFields() throws Exception {
     TestAllTypes.Builder builder = TestAllTypes.newBuilder();
@@ -348,7 +348,7 @@ public class FieldPresenceTest extends TestCase {
     builder.addRepeatedInt32(5678);
     TestAllTypes message = builder.build();
     ByteString data = message.toByteString();
-    
+
     TestOptionalFieldsOnly optionalOnlyMessage =
         TestOptionalFieldsOnly.parseFrom(data);
     // UnknownFieldSet should be empty.
@@ -360,7 +360,7 @@ public class FieldPresenceTest extends TestCase {
     // The repeated field is discarded because it's unknown to the optional-only
     // message.
     assertEquals(0, message.getRepeatedInt32Count());
-    
+
     DynamicMessage dynamicOptionalOnlyMessage =
         DynamicMessage.getDefaultInstance(
             TestOptionalFieldsOnly.getDescriptor())
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 70812b95..8cd1f38d 100644
--- a/java/core/src/test/java/com/google/protobuf/GeneratedMessageTest.java
+++ b/java/core/src/test/java/com/google/protobuf/GeneratedMessageTest.java
@@ -620,6 +620,21 @@ public class GeneratedMessageTest extends TestCase {
     TestUtil.assertExtensionsClear(TestAllExtensions.newBuilder().build());
   }
 
+  public void testUnsetRepeatedExtensionGetField() {
+    TestAllExtensions message = TestAllExtensions.getDefaultInstance();
+    Object value;
+
+    value = message.getField(UnittestProto.repeatedStringExtension.getDescriptor());
+    assertTrue(value instanceof List);
+    assertTrue(((List<?>) value).isEmpty());
+    assertIsUnmodifiable((List<?>) value);
+
+    value = message.getField(UnittestProto.repeatedNestedMessageExtension.getDescriptor());
+    assertTrue(value instanceof List);
+    assertTrue(((List<?>) value).isEmpty());
+    assertIsUnmodifiable((List<?>) value);
+  }
+
   public void testExtensionReflectionGetters() throws Exception {
     TestAllExtensions.Builder builder = TestAllExtensions.newBuilder();
     TestUtil.setAllExtensions(builder);
diff --git a/java/core/src/test/java/com/google/protobuf/IsValidUtf8Test.java b/java/core/src/test/java/com/google/protobuf/IsValidUtf8Test.java
index 8751baae..756049b4 100644
--- a/java/core/src/test/java/com/google/protobuf/IsValidUtf8Test.java
+++ b/java/core/src/test/java/com/google/protobuf/IsValidUtf8Test.java
@@ -30,12 +30,18 @@
 
 package com.google.protobuf;
 
+import static com.google.protobuf.IsValidUtf8TestUtil.DIRECT_NIO_FACTORY;
+import static com.google.protobuf.IsValidUtf8TestUtil.EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT;
+import static com.google.protobuf.IsValidUtf8TestUtil.EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT;
+import static com.google.protobuf.IsValidUtf8TestUtil.HEAP_NIO_FACTORY;
+import static com.google.protobuf.IsValidUtf8TestUtil.LITERAL_FACTORY;
+import static com.google.protobuf.IsValidUtf8TestUtil.testBytes;
+
+import com.google.protobuf.IsValidUtf8TestUtil.ByteStringFactory;
 import com.google.protobuf.IsValidUtf8TestUtil.Shard;
 
 import junit.framework.TestCase;
 
-import java.io.UnsupportedEncodingException;
-
 /**
  * Tests cases for {@link ByteString#isValidUtf8()}. This includes three
  * brute force tests that actually test every permutation of one byte, two byte,
@@ -51,31 +57,33 @@ import java.io.UnsupportedEncodingException;
  * @author martinrb@google.com (Martin Buchholz)
  */
 public class IsValidUtf8Test extends TestCase {
-
   /**
    * Tests that round tripping of all two byte permutations work.
    */
-  public void testIsValidUtf8_1Byte() throws UnsupportedEncodingException {
-    IsValidUtf8TestUtil.testBytes(1,
-        IsValidUtf8TestUtil.EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT);
+  public void testIsValidUtf8_1Byte() {
+    testBytes(LITERAL_FACTORY, 1, EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT);
+    testBytes(HEAP_NIO_FACTORY, 1, EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT);
+    testBytes(DIRECT_NIO_FACTORY, 1, EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT);
   }
 
   /**
    * Tests that round tripping of all two byte permutations work.
    */
-  public void testIsValidUtf8_2Bytes() throws UnsupportedEncodingException {
-    IsValidUtf8TestUtil.testBytes(2,
-        IsValidUtf8TestUtil.EXPECTED_TWO_BYTE_ROUNDTRIPPABLE_COUNT);
+  public void testIsValidUtf8_2Bytes() {
+    testBytes(LITERAL_FACTORY, 2, IsValidUtf8TestUtil.EXPECTED_TWO_BYTE_ROUNDTRIPPABLE_COUNT);
+    testBytes(HEAP_NIO_FACTORY, 2, IsValidUtf8TestUtil.EXPECTED_TWO_BYTE_ROUNDTRIPPABLE_COUNT);
+    testBytes(DIRECT_NIO_FACTORY, 2, IsValidUtf8TestUtil.EXPECTED_TWO_BYTE_ROUNDTRIPPABLE_COUNT);
   }
 
   /**
    * Tests that round tripping of all three byte permutations work.
    */
-  public void testIsValidUtf8_3Bytes() throws UnsupportedEncodingException {
+  public void testIsValidUtf8_3Bytes() {
     // Travis' OOM killer doesn't like this test
     if (System.getenv("TRAVIS") == null) {
-      IsValidUtf8TestUtil.testBytes(3,
-          IsValidUtf8TestUtil.EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT);
+      testBytes(LITERAL_FACTORY, 3, EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT);
+      testBytes(HEAP_NIO_FACTORY, 3, EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT);
+      testBytes(DIRECT_NIO_FACTORY, 3, EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT);
     }
   }
 
@@ -85,8 +93,7 @@ public class IsValidUtf8Test extends TestCase {
    * {@link IsValidUtf8FourByteTest} is used for full coverage. This method
    * tests specific four-byte cases.
    */
-  public void testIsValidUtf8_4BytesSamples()
-      throws UnsupportedEncodingException {
+  public void testIsValidUtf8_4BytesSamples() {
     // Valid 4 byte.
     assertValidUtf8(0xF0, 0xA4, 0xAD, 0xA2);
 
@@ -119,9 +126,7 @@ public class IsValidUtf8Test extends TestCase {
     assertTrue(asBytes("\u024B62\u024B62").isValidUtf8());
 
     // Mixed string
-    assertTrue(
-        asBytes("a\u020ac\u00a2b\\u024B62u020acc\u00a2de\u024B62")
-        .isValidUtf8());
+    assertTrue(asBytes("a\u020ac\u00a2b\\u024B62u020acc\u00a2de\u024B62").isValidUtf8());
 
     // Not a valid string
     assertInvalidUtf8(-1, 0, -1, 0);
@@ -135,36 +140,35 @@ public class IsValidUtf8Test extends TestCase {
     return realBytes;
   }
 
-  private ByteString toByteString(int... bytes) {
-    return ByteString.copyFrom(toByteArray(bytes));
-  }
-
-  private void assertValidUtf8(int[] bytes, boolean not) {
+  private void assertValidUtf8(ByteStringFactory factory, int[] bytes, boolean not) {
     byte[] realBytes = toByteArray(bytes);
     assertTrue(not ^ Utf8.isValidUtf8(realBytes));
     assertTrue(not ^ Utf8.isValidUtf8(realBytes, 0, bytes.length));
-    ByteString lit = ByteString.copyFrom(realBytes);
-    ByteString sub = lit.substring(0, bytes.length);
-    assertTrue(not ^ lit.isValidUtf8());
+    ByteString leaf = factory.newByteString(realBytes);
+    ByteString sub = leaf.substring(0, bytes.length);
+    assertTrue(not ^ leaf.isValidUtf8());
     assertTrue(not ^ sub.isValidUtf8());
     ByteString[] ropes = {
-      RopeByteString.newInstanceForTest(ByteString.EMPTY, lit),
-      RopeByteString.newInstanceForTest(ByteString.EMPTY, sub),
-      RopeByteString.newInstanceForTest(lit, ByteString.EMPTY),
-      RopeByteString.newInstanceForTest(sub, ByteString.EMPTY),
-      RopeByteString.newInstanceForTest(sub, lit)
-    };
+        RopeByteString.newInstanceForTest(ByteString.EMPTY, leaf),
+        RopeByteString.newInstanceForTest(ByteString.EMPTY, sub),
+        RopeByteString.newInstanceForTest(leaf, ByteString.EMPTY),
+        RopeByteString.newInstanceForTest(sub, ByteString.EMPTY),
+        RopeByteString.newInstanceForTest(sub, leaf)};
     for (ByteString rope : ropes) {
       assertTrue(not ^ rope.isValidUtf8());
     }
   }
 
   private void assertValidUtf8(int... bytes) {
-    assertValidUtf8(bytes, false);
+    assertValidUtf8(LITERAL_FACTORY, bytes, false);
+    assertValidUtf8(HEAP_NIO_FACTORY, bytes, false);
+    assertValidUtf8(DIRECT_NIO_FACTORY, bytes, false);
   }
 
   private void assertInvalidUtf8(int... bytes) {
-    assertValidUtf8(bytes, true);
+    assertValidUtf8(LITERAL_FACTORY, bytes, true);
+    assertValidUtf8(HEAP_NIO_FACTORY, bytes, true);
+    assertValidUtf8(DIRECT_NIO_FACTORY, bytes, true);
   }
 
   private static ByteString asBytes(String s) {
@@ -177,7 +181,6 @@ public class IsValidUtf8Test extends TestCase {
     for (Shard shard : IsValidUtf8TestUtil.FOUR_BYTE_SHARDS) {
       actual += shard.expected;
     }
-    assertEquals(IsValidUtf8TestUtil.EXPECTED_FOUR_BYTE_ROUNDTRIPPABLE_COUNT,
-        actual);
+    assertEquals(IsValidUtf8TestUtil.EXPECTED_FOUR_BYTE_ROUNDTRIPPABLE_COUNT, actual);
   }
 }
diff --git a/java/core/src/test/java/com/google/protobuf/IsValidUtf8TestUtil.java b/java/core/src/test/java/com/google/protobuf/IsValidUtf8TestUtil.java
index 321669f3..16a808bf 100644
--- a/java/core/src/test/java/com/google/protobuf/IsValidUtf8TestUtil.java
+++ b/java/core/src/test/java/com/google/protobuf/IsValidUtf8TestUtil.java
@@ -30,9 +30,13 @@
 
 package com.google.protobuf;
 
-import static junit.framework.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
-import java.io.UnsupportedEncodingException;
+import java.lang.ref.SoftReference;
 import java.nio.ByteBuffer;
 import java.nio.CharBuffer;
 import java.nio.charset.CharsetDecoder;
@@ -52,64 +56,105 @@ import java.util.logging.Logger;
  * @author jonp@google.com (Jon Perlow)
  * @author martinrb@google.com (Martin Buchholz)
  */
-class IsValidUtf8TestUtil {
-  private static Logger logger = Logger.getLogger(
-      IsValidUtf8TestUtil.class.getName());
+final class IsValidUtf8TestUtil {
+  private static Logger logger = Logger.getLogger(IsValidUtf8TestUtil.class.getName());
+
+  private IsValidUtf8TestUtil() {}
+
+  static interface ByteStringFactory {
+    ByteString newByteString(byte[] bytes);
+  }
+
+  static final ByteStringFactory LITERAL_FACTORY = new ByteStringFactory() {
+    @Override
+    public ByteString newByteString(byte[] bytes) {
+      return ByteString.wrap(bytes);
+    }
+  };
+
+  static final ByteStringFactory HEAP_NIO_FACTORY = new ByteStringFactory() {
+    @Override
+    public ByteString newByteString(byte[] bytes) {
+      return new NioByteString(ByteBuffer.wrap(bytes));
+    }
+  };
+
+  private static ThreadLocal<SoftReference<ByteBuffer>> directBuffer =
+      new ThreadLocal<SoftReference<ByteBuffer>>();
+
+  /**
+   * Factory for direct {@link ByteBuffer} instances. To reduce direct memory usage, this
+   * uses a thread local direct buffer. This means that each call will overwrite the buffer's
+   * contents from the previous call, so the calling code must be careful not to continue using
+   * a buffer returned from a previous invocation.
+   */
+  static final ByteStringFactory DIRECT_NIO_FACTORY = new ByteStringFactory() {
+    @Override
+    public ByteString newByteString(byte[] bytes) {
+      SoftReference<ByteBuffer> ref = directBuffer.get();
+      ByteBuffer buffer = ref == null ? null : ref.get();
+      if (buffer == null || buffer.capacity() < bytes.length) {
+        buffer = ByteBuffer.allocateDirect(bytes.length);
+        directBuffer.set(new SoftReference<ByteBuffer>(buffer));
+      }
+      buffer.clear();
+      buffer.put(bytes);
+      buffer.flip();
+      return new NioByteString(buffer);
+    }
+  };
 
   // 128 - [chars 0x0000 to 0x007f]
-  static long ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS = 0x007f - 0x0000 + 1;
+  static final long ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS = 0x007f - 0x0000 + 1;
 
   // 128
-  static long EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT =
-      ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS;
+  static final long EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT = ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS;
 
   // 1920 [chars 0x0080 to 0x07FF]
-  static long TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS = 0x07FF - 0x0080 + 1;
+  static final long TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS = 0x07FF - 0x0080 + 1;
 
   // 18,304
-  static long EXPECTED_TWO_BYTE_ROUNDTRIPPABLE_COUNT =
+  static final long EXPECTED_TWO_BYTE_ROUNDTRIPPABLE_COUNT =
       // Both bytes are one byte characters
       (long) Math.pow(EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT, 2) +
       // The possible number of two byte characters
       TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS;
 
   // 2048
-  static long THREE_BYTE_SURROGATES = 2 * 1024;
+  static final long THREE_BYTE_SURROGATES = 2 * 1024;
 
   // 61,440 [chars 0x0800 to 0xFFFF, minus surrogates]
-  static long THREE_BYTE_ROUNDTRIPPABLE_CHARACTERS =
+  static final long THREE_BYTE_ROUNDTRIPPABLE_CHARACTERS =
       0xFFFF - 0x0800 + 1 - THREE_BYTE_SURROGATES;
 
   // 2,650,112
-  static long EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT =
+  static final long EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT =
       // All one byte characters
       (long) Math.pow(EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT, 3) +
       // One two byte character and a one byte character
-      2 * TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS *
-          ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS +
-       // Three byte characters
+      2 * TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS * ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS +
+      // Three byte characters
       THREE_BYTE_ROUNDTRIPPABLE_CHARACTERS;
 
   // 1,048,576 [chars 0x10000L to 0x10FFFF]
-  static long FOUR_BYTE_ROUNDTRIPPABLE_CHARACTERS = 0x10FFFF - 0x10000L + 1;
+  static final long FOUR_BYTE_ROUNDTRIPPABLE_CHARACTERS = 0x10FFFF - 0x10000L + 1;
 
   // 289,571,839
-  static long EXPECTED_FOUR_BYTE_ROUNDTRIPPABLE_COUNT =
+  static final long EXPECTED_FOUR_BYTE_ROUNDTRIPPABLE_COUNT =
       // All one byte characters
       (long) Math.pow(EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT, 4) +
       // One and three byte characters
-      2 * THREE_BYTE_ROUNDTRIPPABLE_CHARACTERS *
-          ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS +
+      2 * THREE_BYTE_ROUNDTRIPPABLE_CHARACTERS * ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS +
       // Two two byte characters
       TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS * TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS +
       // Permutations of one and two byte characters
-      3 * TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS *
-          ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS *
-          ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS +
+      3 * TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS * ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS
+      * ONE_BYTE_ROUNDTRIPPABLE_CHARACTERS
+      +
       // Four byte characters
       FOUR_BYTE_ROUNDTRIPPABLE_CHARACTERS;
 
-  static class Shard {
+  static final class Shard {
     final long index;
     final long start;
     final long lim;
@@ -138,7 +183,7 @@ class IsValidUtf8TestUtil {
 
     // 97-111 are all 2342912
     for (int i = 97; i <= 111; i++) {
-     expected[i] = 2342912;
+      expected[i] = 2342912;
     }
 
     // 113-117 are all 1048576
@@ -158,22 +203,18 @@ class IsValidUtf8TestUtil {
     return expected;
   }
 
-  static final List<Shard> FOUR_BYTE_SHARDS = generateFourByteShards(
-      128, FOUR_BYTE_SHARDS_EXPECTED_ROUNTRIPPABLES);
+  static final List<Shard> FOUR_BYTE_SHARDS =
+      generateFourByteShards(128, FOUR_BYTE_SHARDS_EXPECTED_ROUNTRIPPABLES);
 
 
-  private static List<Shard> generateFourByteShards(
-      int numShards, long[] expected) {
+  private static List<Shard> generateFourByteShards(int numShards, long[] expected) {
     assertEquals(numShards, expected.length);
     List<Shard> shards = new ArrayList<Shard>(numShards);
     long LIM = 1L << 32;
     long increment = LIM / numShards;
     assertTrue(LIM % numShards == 0);
     for (int i = 0; i < numShards; i++) {
-      shards.add(new Shard(i,
-          increment * i,
-          increment * (i + 1),
-          expected[i]));
+      shards.add(new Shard(i, increment * i, increment * (i + 1), expected[i]));
     }
     return shards;
   }
@@ -182,12 +223,12 @@ class IsValidUtf8TestUtil {
    * Helper to run the loop to test all the permutations for the number of bytes
    * specified.
    *
+   * @param factory the factory for {@link ByteString} instances.
    * @param numBytes the number of bytes in the byte array
    * @param expectedCount the expected number of roundtrippable permutations
    */
-  static void testBytes(int numBytes, long expectedCount)
-      throws UnsupportedEncodingException {
-    testBytes(numBytes, expectedCount, 0, -1);
+  static void testBytes(ByteStringFactory factory, int numBytes, long expectedCount) {
+    testBytes(factory, numBytes, expectedCount, 0, -1);
   }
 
   /**
@@ -195,14 +236,15 @@ class IsValidUtf8TestUtil {
    * specified. This overload is useful for debugging to get the loop to start
    * at a certain character.
    *
+   * @param factory the factory for {@link ByteString} instances.
    * @param numBytes the number of bytes in the byte array
    * @param expectedCount the expected number of roundtrippable permutations
    * @param start the starting bytes encoded as a long as big-endian
    * @param lim the limit of bytes to process encoded as a long as big-endian,
    *     or -1 to mean the max limit for numBytes
    */
-  static void testBytes(int numBytes, long expectedCount, long start, long lim)
-      throws UnsupportedEncodingException {
+  static void testBytes(
+      ByteStringFactory factory, int numBytes, long expectedCount, long start, long lim) {
     Random rnd = new Random();
     byte[] bytes = new byte[numBytes];
 
@@ -217,7 +259,7 @@ class IsValidUtf8TestUtil {
         bytes[bytes.length - i - 1] = (byte) tmpByteChar;
         tmpByteChar = tmpByteChar >> 8;
       }
-      ByteString bs = ByteString.copyFrom(bytes);
+      ByteString bs = factory.newByteString(bytes);
       boolean isRoundTrippable = bs.isValidUtf8();
       String s = new String(bytes, Internal.UTF_8);
       byte[] bytesReencoded = s.getBytes(Internal.UTF_8);
@@ -236,14 +278,15 @@ class IsValidUtf8TestUtil {
       int i = rnd.nextInt(numBytes);
       int j = rnd.nextInt(numBytes);
       if (j < i) {
-        int tmp = i; i = j; j = tmp;
+        int tmp = i;
+        i = j;
+        j = tmp;
       }
       int state1 = Utf8.partialIsValidUtf8(Utf8.COMPLETE, bytes, 0, i);
       int state2 = Utf8.partialIsValidUtf8(state1, bytes, i, j);
       int state3 = Utf8.partialIsValidUtf8(state2, bytes, j, numBytes);
       if (isRoundTrippable != (state3 == Utf8.COMPLETE)) {
-        System.out.printf("state=%04x %04x %04x i=%d j=%d%n",
-                          state1, state2, state3, i, j);
+        System.out.printf("state=%04x %04x %04x i=%d j=%d%n", state1, state2, state3, i, j);
         outputFailure(byteChar, bytes, bytesReencoded);
       }
       assertEquals(isRoundTrippable, (state3 == Utf8.COMPLETE));
@@ -251,36 +294,24 @@ class IsValidUtf8TestUtil {
       // Test ropes built out of small partial sequences
       ByteString rope = RopeByteString.newInstanceForTest(
           bs.substring(0, i),
-          RopeByteString.newInstanceForTest(
-              bs.substring(i, j),
-              bs.substring(j, numBytes)));
+          RopeByteString.newInstanceForTest(bs.substring(i, j), bs.substring(j, numBytes)));
       assertSame(RopeByteString.class, rope.getClass());
 
-      ByteString[] byteStrings = { bs, bs.substring(0, numBytes), rope };
+      ByteString[] byteStrings = {bs, bs.substring(0, numBytes), rope};
       for (ByteString x : byteStrings) {
-        assertEquals(isRoundTrippable,
-                     x.isValidUtf8());
-        assertEquals(state3,
-                     x.partialIsValidUtf8(Utf8.COMPLETE, 0, numBytes));
-
-        assertEquals(state1,
-                     x.partialIsValidUtf8(Utf8.COMPLETE, 0, i));
-        assertEquals(state1,
-                     x.substring(0, i).partialIsValidUtf8(Utf8.COMPLETE, 0, i));
-        assertEquals(state2,
-                     x.partialIsValidUtf8(state1, i, j - i));
-        assertEquals(state2,
-                     x.substring(i, j).partialIsValidUtf8(state1, 0, j - i));
-        assertEquals(state3,
-                     x.partialIsValidUtf8(state2, j, numBytes - j));
-        assertEquals(state3,
-                     x.substring(j, numBytes)
-                     .partialIsValidUtf8(state2, 0, numBytes - j));
+        assertEquals(isRoundTrippable, x.isValidUtf8());
+        assertEquals(state3, x.partialIsValidUtf8(Utf8.COMPLETE, 0, numBytes));
+
+        assertEquals(state1, x.partialIsValidUtf8(Utf8.COMPLETE, 0, i));
+        assertEquals(state1, x.substring(0, i).partialIsValidUtf8(Utf8.COMPLETE, 0, i));
+        assertEquals(state2, x.partialIsValidUtf8(state1, i, j - i));
+        assertEquals(state2, x.substring(i, j).partialIsValidUtf8(state1, 0, j - i));
+        assertEquals(state3, x.partialIsValidUtf8(state2, j, numBytes - j));
+        assertEquals(state3, x.substring(j, numBytes).partialIsValidUtf8(state2, 0, numBytes - j));
       }
 
       // ByteString reduplication should not affect its UTF-8 validity.
-      ByteString ropeADope =
-          RopeByteString.newInstanceForTest(bs, bs.substring(0, numBytes));
+      ByteString ropeADope = RopeByteString.newInstanceForTest(bs, bs.substring(0, numBytes));
       assertEquals(isRoundTrippable, ropeADope.isValidUtf8());
 
       if (isRoundTrippable) {
@@ -288,8 +319,7 @@ class IsValidUtf8TestUtil {
       }
       count++;
       if (byteChar != 0 && byteChar % 1000000L == 0) {
-        logger.info("Processed " + (byteChar / 1000000L) +
-            " million characters");
+        logger.info("Processed " + (byteChar / 1000000L) + " million characters");
       }
     }
     logger.info("Round tripped " + countRoundTripped + " of " + count);
@@ -303,25 +333,26 @@ class IsValidUtf8TestUtil {
    * actual String class, it's possible for incompatibilities to develop
    * (although unlikely).
    *
+   * @param factory the factory for {@link ByteString} instances.
    * @param numBytes the number of bytes in the byte array
    * @param expectedCount the expected number of roundtrippable permutations
    * @param start the starting bytes encoded as a long as big-endian
    * @param lim the limit of bytes to process encoded as a long as big-endian,
    *     or -1 to mean the max limit for numBytes
    */
-  void testBytesUsingByteBuffers(
-      int numBytes, long expectedCount, long start, long lim)
-      throws UnsupportedEncodingException {
-    CharsetDecoder decoder = Internal.UTF_8.newDecoder()
-        .onMalformedInput(CodingErrorAction.REPLACE)
-        .onUnmappableCharacter(CodingErrorAction.REPLACE);
-    CharsetEncoder encoder = Internal.UTF_8.newEncoder()
-        .onMalformedInput(CodingErrorAction.REPLACE)
-        .onUnmappableCharacter(CodingErrorAction.REPLACE);
+  static void testBytesUsingByteBuffers(
+      ByteStringFactory factory, int numBytes, long expectedCount, long start, long lim) {
+    CharsetDecoder decoder =
+        Internal.UTF_8.newDecoder()
+            .onMalformedInput(CodingErrorAction.REPLACE)
+            .onUnmappableCharacter(CodingErrorAction.REPLACE);
+    CharsetEncoder encoder =
+        Internal.UTF_8.newEncoder()
+            .onMalformedInput(CodingErrorAction.REPLACE)
+            .onUnmappableCharacter(CodingErrorAction.REPLACE);
     byte[] bytes = new byte[numBytes];
     int maxChars = (int) (decoder.maxCharsPerByte() * numBytes) + 1;
-    char[] charsDecoded =
-        new char[(int) (decoder.maxCharsPerByte() * numBytes) + 1];
+    char[] charsDecoded = new char[(int) (decoder.maxCharsPerByte() * numBytes) + 1];
     int maxBytes = (int) (encoder.maxBytesPerChar() * maxChars) + 1;
     byte[] bytesReencoded = new byte[maxBytes];
 
@@ -347,7 +378,7 @@ class IsValidUtf8TestUtil {
         bytes[bytes.length - i - 1] = (byte) tmpByteChar;
         tmpByteChar = tmpByteChar >> 8;
       }
-      boolean isRoundTrippable = ByteString.copyFrom(bytes).isValidUtf8();
+      boolean isRoundTrippable = factory.newByteString(bytes).isValidUtf8();
       CoderResult result = decoder.decode(bb, cb, true);
       assertFalse(result.isError());
       result = decoder.flush(cb);
@@ -382,8 +413,7 @@ class IsValidUtf8TestUtil {
         countRoundTripped++;
       }
       if (byteChar != 0 && byteChar % 1000000 == 0) {
-        logger.info("Processed " + (byteChar / 1000000) +
-            " million characters");
+        logger.info("Processed " + (byteChar / 1000000) + " million characters");
       }
     }
     logger.info("Round tripped " + countRoundTripped + " of " + count);
@@ -394,10 +424,9 @@ class IsValidUtf8TestUtil {
     outputFailure(byteChar, bytes, after, after.length);
   }
 
-  private static void outputFailure(long byteChar, byte[] bytes, byte[] after,
-      int len) {
-    fail("Failure: (" + Long.toHexString(byteChar) + ") " +
-        toHexString(bytes) + " => " + toHexString(after, len));
+  private static void outputFailure(long byteChar, byte[] bytes, byte[] after, int len) {
+    fail("Failure: (" + Long.toHexString(byteChar) + ") " + toHexString(bytes) + " => "
+        + toHexString(after, len));
   }
 
   private static String toHexString(byte[] b) {
@@ -416,5 +445,4 @@ class IsValidUtf8TestUtil {
     s.append("\"");
     return s.toString();
   }
-
 }
diff --git a/java/core/src/test/java/com/google/protobuf/LazyFieldLiteTest.java b/java/core/src/test/java/com/google/protobuf/LazyFieldLiteTest.java
index 211b5697..8d1de6dc 100644
--- a/java/core/src/test/java/com/google/protobuf/LazyFieldLiteTest.java
+++ b/java/core/src/test/java/com/google/protobuf/LazyFieldLiteTest.java
@@ -36,9 +36,10 @@ import static protobuf_unittest.UnittestProto.optionalInt64Extension;
 import protobuf_unittest.UnittestProto.TestAllExtensions;
 import protobuf_unittest.UnittestProto.TestAllTypes;
 
-import java.io.IOException;
 import junit.framework.TestCase;
 
+import java.io.IOException;
+
 /**
  * Unit test for {@link LazyFieldLite}.
  *
diff --git a/java/core/src/test/java/com/google/protobuf/LazyFieldTest.java b/java/core/src/test/java/com/google/protobuf/LazyFieldTest.java
index 2b900065..ce473ae9 100644
--- a/java/core/src/test/java/com/google/protobuf/LazyFieldTest.java
+++ b/java/core/src/test/java/com/google/protobuf/LazyFieldTest.java
@@ -33,9 +33,10 @@ package com.google.protobuf;
 import protobuf_unittest.UnittestProto.TestAllExtensions;
 import protobuf_unittest.UnittestProto.TestAllTypes;
 
-import java.io.IOException;
 import junit.framework.TestCase;
 
+import java.io.IOException;
+
 /**
  * Unit test for {@link LazyField}.
  *
diff --git a/java/core/src/test/java/com/google/protobuf/LiteEqualsAndHashTest.java b/java/core/src/test/java/com/google/protobuf/LiteEqualsAndHashTest.java
index 035917c8..29e8d875 100644
--- a/java/core/src/test/java/com/google/protobuf/LiteEqualsAndHashTest.java
+++ b/java/core/src/test/java/com/google/protobuf/LiteEqualsAndHashTest.java
@@ -33,6 +33,8 @@ package com.google.protobuf;
 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;
 
@@ -83,6 +85,16 @@ public class LiteEqualsAndHashTest extends TestCase {
     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 testEqualsAndHashCodeWithUnknownFields() throws InvalidProtocolBufferException {
     Foo fooWithOnlyValue = Foo.newBuilder()
         .setValue(1)
@@ -105,4 +117,9 @@ public class LiteEqualsAndHashTest extends TestCase {
     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/LiteTest.java b/java/core/src/test/java/com/google/protobuf/LiteTest.java
index b1f298ff..9e503cc3 100644
--- a/java/core/src/test/java/com/google/protobuf/LiteTest.java
+++ b/java/core/src/test/java/com/google/protobuf/LiteTest.java
@@ -49,6 +49,7 @@ import junit.framework.TestCase;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.NotSerializableException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 
@@ -128,33 +129,7 @@ public class LiteTest extends TestCase {
     assertEquals(7, message2.getExtension(
         UnittestLite.optionalNestedMessageExtensionLite).getBb());
   }
-
-  public void testSerialize() throws Exception {
-    ByteArrayOutputStream baos = new ByteArrayOutputStream();
-    TestAllTypesLite expected =
-      TestAllTypesLite.newBuilder()
-                      .setOptionalInt32(123)
-                      .addRepeatedString("hello")
-                      .setOptionalNestedMessage(
-                          TestAllTypesLite.NestedMessage.newBuilder().setBb(7))
-                      .build();
-    ObjectOutputStream out = new ObjectOutputStream(baos);
-    try {
-      out.writeObject(expected);
-    } finally {
-      out.close();
-    }
-    ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-    ObjectInputStream in = new ObjectInputStream(bais);
-    TestAllTypesLite actual = (TestAllTypesLite) in.readObject();
-    assertEquals(expected.getOptionalInt32(), actual.getOptionalInt32());
-    assertEquals(expected.getRepeatedStringCount(),
-        actual.getRepeatedStringCount());
-    assertEquals(expected.getRepeatedString(0),
-        actual.getRepeatedString(0));
-    assertEquals(expected.getOptionalNestedMessage().getBb(),
-        actual.getOptionalNestedMessage().getBb());
-  }
+  
   
   public void testClone() {
     TestAllTypesLite.Builder expected = TestAllTypesLite.newBuilder()
@@ -1459,4 +1434,168 @@ public class LiteTest extends TestCase {
         11, (int) extendableMessage.getExtension(
             UnittestLite.optionalFixed32ExtensionLite));
   }
+
+  public void testToStringDefaultInstance() throws Exception {
+    assertToStringEquals("", TestAllTypesLite.getDefaultInstance());
+  }
+
+  public void testToStringPrimitives() throws Exception {
+    TestAllTypesLite proto = TestAllTypesLite.newBuilder()
+        .setOptionalInt32(1)
+        .setOptionalInt64(9223372036854775807L)
+        .build();
+    assertToStringEquals("optional_int32: 1\noptional_int64: 9223372036854775807", proto);
+
+    proto = TestAllTypesLite.newBuilder()
+        .setOptionalBool(true)
+        .setOptionalNestedEnum(TestAllTypesLite.NestedEnum.BAZ)
+        .build();
+    assertToStringEquals("optional_bool: true\noptional_nested_enum: BAZ", proto);
+
+    proto = TestAllTypesLite.newBuilder()
+        .setOptionalFloat(2.72f)
+        .setOptionalDouble(3.14)
+        .build();
+    assertToStringEquals("optional_float: 2.72\noptional_double: 3.14", proto);
+  }
+
+  public void testToStringStringFields() throws Exception {
+    TestAllTypesLite proto = TestAllTypesLite.newBuilder()
+        .setOptionalString("foo\"bar\nbaz\\")
+        .build();
+    assertToStringEquals("optional_string: \"foo\\\"bar\\nbaz\\\\\"", proto);
+
+    proto = TestAllTypesLite.newBuilder()
+        .setOptionalString("\u6587")
+        .build();
+    assertToStringEquals("optional_string: \"\\346\\226\\207\"", proto);
+  }
+
+  public void testToStringNestedMessage() throws Exception {
+    TestAllTypesLite proto = TestAllTypesLite.newBuilder()
+        .setOptionalNestedMessage(TestAllTypesLite.NestedMessage.getDefaultInstance())
+        .build();
+    assertToStringEquals("optional_nested_message {\n}", proto);
+
+    proto = TestAllTypesLite.newBuilder()
+        .setOptionalNestedMessage(
+            TestAllTypesLite.NestedMessage.newBuilder().setBb(7))
+        .build();
+    assertToStringEquals("optional_nested_message {\n  bb: 7\n}", proto);
+  }
+
+  public void testToStringRepeatedFields() throws Exception {
+    TestAllTypesLite proto = TestAllTypesLite.newBuilder()
+        .addRepeatedInt32(32)
+        .addRepeatedInt32(32)
+        .addRepeatedInt64(64)
+        .build();
+    assertToStringEquals("repeated_int32: 32\nrepeated_int32: 32\nrepeated_int64: 64", proto);
+
+    proto = TestAllTypesLite.newBuilder()
+        .addRepeatedLazyMessage(
+            TestAllTypesLite.NestedMessage.newBuilder().setBb(7))
+        .addRepeatedLazyMessage(
+            TestAllTypesLite.NestedMessage.newBuilder().setBb(8))
+        .build();
+    assertToStringEquals(
+        "repeated_lazy_message {\n  bb: 7\n}\nrepeated_lazy_message {\n  bb: 8\n}",
+        proto);
+  }
+
+  public void testToStringForeignFields() throws Exception {
+    TestAllTypesLite proto = TestAllTypesLite.newBuilder()
+        .setOptionalForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR)
+        .setOptionalForeignMessage(
+            ForeignMessageLite.newBuilder()
+            .setC(3))
+        .build();
+    assertToStringEquals(
+        "optional_foreign_message {\n  c: 3\n}\noptional_foreign_enum: FOREIGN_LITE_BAR",
+        proto);
+  }
+
+  public void testToStringExtensions() throws Exception {
+    TestAllExtensionsLite message = TestAllExtensionsLite.newBuilder()
+        .setExtension(UnittestLite.optionalInt32ExtensionLite, 123)
+        .addExtension(UnittestLite.repeatedStringExtensionLite, "spam")
+        .addExtension(UnittestLite.repeatedStringExtensionLite, "eggs")
+        .setExtension(UnittestLite.optionalNestedEnumExtensionLite,
+            TestAllTypesLite.NestedEnum.BAZ)
+        .setExtension(UnittestLite.optionalNestedMessageExtensionLite,
+            TestAllTypesLite.NestedMessage.newBuilder().setBb(7).build())
+        .build();
+    assertToStringEquals(
+        "[1]: 123\n[18] {\n  bb: 7\n}\n[21]: 3\n[44]: \"spam\"\n[44]: \"eggs\"",
+        message);
+  }
+
+  public void testToStringUnknownFields() throws Exception {
+    TestAllExtensionsLite messageWithExtensions = TestAllExtensionsLite.newBuilder()
+        .setExtension(UnittestLite.optionalInt32ExtensionLite, 123)
+        .addExtension(UnittestLite.repeatedStringExtensionLite, "spam")
+        .addExtension(UnittestLite.repeatedStringExtensionLite, "eggs")
+        .setExtension(UnittestLite.optionalNestedEnumExtensionLite,
+            TestAllTypesLite.NestedEnum.BAZ)
+        .setExtension(UnittestLite.optionalNestedMessageExtensionLite,
+            TestAllTypesLite.NestedMessage.newBuilder().setBb(7).build())
+        .build();
+    TestAllExtensionsLite messageWithUnknownFields = TestAllExtensionsLite.parseFrom(
+        messageWithExtensions.toByteArray());
+    assertToStringEquals(
+        "1: 123\n18: \"\\b\\a\"\n21: 3\n44: \"spam\"\n44: \"eggs\"",
+        messageWithUnknownFields);
+  }
+
+  // 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
+  // comparison as it contains unstable addresses.
+  private static void assertToStringEquals(String expected, MessageLite message) {
+    String toString = message.toString();
+    assertEquals('#', toString.charAt(0));
+    if (toString.indexOf("\n") >= 0) {
+      toString = toString.substring(toString.indexOf("\n") + 1);
+    } else {
+      toString = "";
+    }
+    assertEquals(expected, toString);
+  }
+  
+  public void testParseLazy() throws Exception {
+    ByteString bb = TestAllTypesLite.newBuilder()
+        .setOptionalLazyMessage(NestedMessage.newBuilder()
+            .setBb(11)
+            .build())
+        .build().toByteString();
+    ByteString cc = TestAllTypesLite.newBuilder()
+        .setOptionalLazyMessage(NestedMessage.newBuilder()
+            .setCc(22)
+            .build())
+        .build().toByteString();
+    
+    ByteString concat = bb.concat(cc);
+    TestAllTypesLite message = TestAllTypesLite.parseFrom(concat);
+
+    assertEquals(11, message.getOptionalLazyMessage().getBb());
+    assertEquals(22L, message.getOptionalLazyMessage().getCc());
+  }
+  
+  public void testParseLazy_oneOf() throws Exception {
+    ByteString bb = TestAllTypesLite.newBuilder()
+        .setOneofLazyNestedMessage(NestedMessage.newBuilder()
+            .setBb(11)
+            .build())
+        .build().toByteString();
+    ByteString cc = TestAllTypesLite.newBuilder()
+        .setOneofLazyNestedMessage(NestedMessage.newBuilder()
+            .setCc(22)
+            .build())
+        .build().toByteString();
+    
+    ByteString concat = bb.concat(cc);
+    TestAllTypesLite message = TestAllTypesLite.parseFrom(concat);
+
+    assertEquals(11, message.getOneofLazyNestedMessage().getBb());
+    assertEquals(22L, message.getOneofLazyNestedMessage().getCc());
+  }
 }
diff --git a/java/core/src/test/java/com/google/protobuf/LiteralByteStringTest.java b/java/core/src/test/java/com/google/protobuf/LiteralByteStringTest.java
index 68b55ceb..2e7792a8 100644
--- a/java/core/src/test/java/com/google/protobuf/LiteralByteStringTest.java
+++ b/java/core/src/test/java/com/google/protobuf/LiteralByteStringTest.java
@@ -47,9 +47,9 @@ import java.util.List;
 import java.util.NoSuchElementException;
 
 /**
- * Test {@link LiteralByteString} by setting up a reference string in {@link #setUp()}.
- * This class is designed to be extended for testing extensions of {@link LiteralByteString}
- * such as {@link BoundedByteString}, see {@link BoundedByteStringTest}.
+ * Test {@code LiteralByteString} by setting up a reference string in {@link #setUp()}.
+ * This class is designed to be extended for testing extensions of {@code LiteralByteString}
+ * such as {@code BoundedByteString}, see {@link BoundedByteStringTest}.
  *
  * @author carlanton@google.com (Carl Haverl)
  */
@@ -304,25 +304,75 @@ public class LiteralByteStringTest extends TestCase {
         Arrays.equals(referenceBytes, roundTripBytes));
   }
 
-  public void testWriteTo_mutating() throws IOException {
+  public void testWriteToShouldNotExposeInternalBufferToOutputStream() throws IOException {
     OutputStream os = new OutputStream() {
       @Override
       public void write(byte[] b, int off, int len) {
-        for (int x = 0; x < len; ++x) {
-          b[off + x] = (byte) 0;
-        }
+        Arrays.fill(b, off, off + len, (byte) 0);
       }
 
       @Override
       public void write(int b) {
-        // Purposefully left blank.
+        throw new UnsupportedOperationException();
       }
     };
 
     stringUnderTest.writeTo(os);
-    byte[] newBytes = stringUnderTest.toByteArray();
     assertTrue(classUnderTest + ".writeTo() must not grant access to underlying array",
-        Arrays.equals(referenceBytes, newBytes));
+        Arrays.equals(referenceBytes, stringUnderTest.toByteArray()));
+  }
+
+  public void testWriteToInternalShouldExposeInternalBufferToOutputStream() throws IOException {
+    OutputStream os = new OutputStream() {
+      @Override
+      public void write(byte[] b, int off, int len) {
+        Arrays.fill(b, off, off + len, (byte) 0);
+      }
+
+      @Override
+      public void write(int b) {
+        throw new UnsupportedOperationException();
+      }
+    };
+
+    stringUnderTest.writeToInternal(os, 0, stringUnderTest.size());
+    byte[] allZeros = new byte[stringUnderTest.size()];
+    assertTrue(classUnderTest + ".writeToInternal() must grant access to underlying array",
+        Arrays.equals(allZeros, stringUnderTest.toByteArray()));
+  }
+
+  public void testWriteToShouldExposeInternalBufferToByteOutput() throws IOException {
+    ByteOutput out = new ByteOutput() {
+      @Override
+      public void write(byte value) throws IOException {
+        throw new UnsupportedOperationException();
+      }
+
+      @Override
+      public void write(byte[] value, int offset, int length) throws IOException {
+        throw new UnsupportedOperationException();
+      }
+
+      @Override
+      public void writeLazy(byte[] value, int offset, int length) throws IOException {
+        Arrays.fill(value, offset, offset + length, (byte) 0);
+      }
+
+      @Override
+      public void write(ByteBuffer value) throws IOException {
+        throw new UnsupportedOperationException();
+      }
+
+      @Override
+      public void writeLazy(ByteBuffer value) throws IOException {
+        throw new UnsupportedOperationException();
+      }
+    };
+
+    stringUnderTest.writeTo(out);
+    byte[] allZeros = new byte[stringUnderTest.size()];
+    assertTrue(classUnderTest + ".writeToInternal() must grant access to underlying array",
+        Arrays.equals(allZeros, stringUnderTest.toByteArray()));
   }
 
   public void testNewOutput() throws IOException {
diff --git a/java/core/src/test/java/com/google/protobuf/MapForProto2LiteTest.java b/java/core/src/test/java/com/google/protobuf/MapForProto2LiteTest.java
index 3d8c9bc4..d79d0029 100644
--- a/java/core/src/test/java/com/google/protobuf/MapForProto2LiteTest.java
+++ b/java/core/src/test/java/com/google/protobuf/MapForProto2LiteTest.java
@@ -432,7 +432,7 @@ public class MapForProto2LiteTest extends TestCase {
     assertEquals(1, messageWithUnknownEnums.getInt32ToInt32Field().get(1).intValue());
     assertEquals(54321, messageWithUnknownEnums.getInt32ToInt32Field().get(2).intValue());
   }
-  
+
 
   public void testIterationOrder() throws Exception {
     TestMap.Builder builder = TestMap.newBuilder();
diff --git a/java/core/src/test/java/com/google/protobuf/MapForProto2Test.java b/java/core/src/test/java/com/google/protobuf/MapForProto2Test.java
index 1fa3cbdb..73154c0f 100644
--- a/java/core/src/test/java/com/google/protobuf/MapForProto2Test.java
+++ b/java/core/src/test/java/com/google/protobuf/MapForProto2Test.java
@@ -36,7 +36,6 @@ import map_test.MapForProto2TestProto.TestMap.MessageValue;
 import map_test.MapForProto2TestProto.TestMap.MessageWithRequiredFields;
 import map_test.MapForProto2TestProto.TestRecursiveMap;
 import map_test.MapForProto2TestProto.TestUnknownEnumValue;
-
 import junit.framework.TestCase;
 
 import java.util.ArrayList;
diff --git a/java/core/src/test/java/com/google/protobuf/MapTest.java b/java/core/src/test/java/com/google/protobuf/MapTest.java
index 0e5c1284..1dc5787d 100644
--- a/java/core/src/test/java/com/google/protobuf/MapTest.java
+++ b/java/core/src/test/java/com/google/protobuf/MapTest.java
@@ -37,7 +37,6 @@ import com.google.protobuf.Descriptors.FieldDescriptor;
 import map_test.MapTestProto.TestMap;
 import map_test.MapTestProto.TestMap.MessageValue;
 import map_test.MapTestProto.TestOnChangeEventPropagation;
-
 import junit.framework.TestCase;
 
 import java.util.ArrayList;
diff --git a/java/core/src/test/java/com/google/protobuf/MessageTest.java b/java/core/src/test/java/com/google/protobuf/MessageTest.java
index abcd3a1d..dcd1aba7 100644
--- a/java/core/src/test/java/com/google/protobuf/MessageTest.java
+++ b/java/core/src/test/java/com/google/protobuf/MessageTest.java
@@ -30,11 +30,11 @@
 
 package com.google.protobuf;
 
-import protobuf_unittest.UnittestProto.TestAllTypes;
+import protobuf_unittest.UnittestProto.ForeignMessage;
 import protobuf_unittest.UnittestProto.TestAllExtensions;
+import protobuf_unittest.UnittestProto.TestAllTypes;
 import protobuf_unittest.UnittestProto.TestRequired;
 import protobuf_unittest.UnittestProto.TestRequiredForeign;
-import protobuf_unittest.UnittestProto.ForeignMessage;
 
 import junit.framework.TestCase;
 
diff --git a/java/core/src/test/java/com/google/protobuf/NestedBuildersTest.java b/java/core/src/test/java/com/google/protobuf/NestedBuildersTest.java
index 23653126..542e28c0 100644
--- a/java/core/src/test/java/com/google/protobuf/NestedBuildersTest.java
+++ b/java/core/src/test/java/com/google/protobuf/NestedBuildersTest.java
@@ -35,8 +35,8 @@ import protobuf_unittest.Wheel;
 
 import junit.framework.TestCase;
 
-import java.util.List;
 import java.util.ArrayList;
+import java.util.List;
 
 /**
  * Test cases that exercise end-to-end use cases involving
diff --git a/java/core/src/test/java/com/google/protobuf/NioByteStringTest.java b/java/core/src/test/java/com/google/protobuf/NioByteStringTest.java
index e40a3662..6be5b93c 100644
--- a/java/core/src/test/java/com/google/protobuf/NioByteStringTest.java
+++ b/java/core/src/test/java/com/google/protobuf/NioByteStringTest.java
@@ -41,6 +41,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
+import java.io.OutputStream;
 import java.io.UnsupportedEncodingException;
 import java.nio.BufferOverflowException;
 import java.nio.ByteBuffer;
@@ -56,11 +57,12 @@ public class NioByteStringTest extends TestCase {
   private static final String CLASSNAME = NioByteString.class.getSimpleName();
   private static final byte[] BYTES = ByteStringTest.getTestBytes(1234, 11337766L);
   private static final int EXPECTED_HASH = ByteString.wrap(BYTES).hashCode();
-  private static final ByteBuffer BUFFER = ByteBuffer.wrap(BYTES.clone());
-  private static final ByteString TEST_STRING = new NioByteString(BUFFER);
+
+  private final ByteBuffer backingBuffer = ByteBuffer.wrap(BYTES.clone());
+  private final ByteString testString = new NioByteString(backingBuffer);
 
   public void testExpectedType() {
-    String actualClassName = getActualClassName(TEST_STRING);
+    String actualClassName = getActualClassName(testString);
     assertEquals(CLASSNAME + " should match type exactly", CLASSNAME, actualClassName);
   }
 
@@ -73,14 +75,14 @@ public class NioByteStringTest extends TestCase {
   public void testByteAt() {
     boolean stillEqual = true;
     for (int i = 0; stillEqual && i < BYTES.length; ++i) {
-      stillEqual = (BYTES[i] == TEST_STRING.byteAt(i));
+      stillEqual = (BYTES[i] == testString.byteAt(i));
     }
     assertTrue(CLASSNAME + " must capture the right bytes", stillEqual);
   }
 
   public void testByteIterator() {
     boolean stillEqual = true;
-    ByteString.ByteIterator iter = TEST_STRING.iterator();
+    ByteString.ByteIterator iter = testString.iterator();
     for (int i = 0; stillEqual && i < BYTES.length; ++i) {
       stillEqual = (iter.hasNext() && BYTES[i] == iter.nextByte());
     }
@@ -98,7 +100,7 @@ public class NioByteStringTest extends TestCase {
   public void testByteIterable() {
     boolean stillEqual = true;
     int j = 0;
-    for (byte quantum : TEST_STRING) {
+    for (byte quantum : testString) {
       stillEqual = (BYTES[j] == quantum);
       ++j;
     }
@@ -108,15 +110,15 @@ public class NioByteStringTest extends TestCase {
 
   public void testSize() {
     assertEquals(CLASSNAME + " must have the expected size", BYTES.length,
-        TEST_STRING.size());
+        testString.size());
   }
 
   public void testGetTreeDepth() {
-    assertEquals(CLASSNAME + " must have depth 0", 0, TEST_STRING.getTreeDepth());
+    assertEquals(CLASSNAME + " must have depth 0", 0, testString.getTreeDepth());
   }
 
   public void testIsBalanced() {
-    assertTrue(CLASSNAME + " is technically balanced", TEST_STRING.isBalanced());
+    assertTrue(CLASSNAME + " is technically balanced", testString.isBalanced());
   }
 
   public void testCopyTo_ByteArrayOffsetLength() {
@@ -124,7 +126,7 @@ public class NioByteStringTest extends TestCase {
     int length = 100;
     byte[] destination = new byte[destinationOffset + length];
     int sourceOffset = 213;
-    TEST_STRING.copyTo(destination, sourceOffset, destinationOffset, length);
+    testString.copyTo(destination, sourceOffset, destinationOffset, length);
     boolean stillEqual = true;
     for (int i = 0; stillEqual && i < length; ++i) {
       stillEqual = BYTES[i + sourceOffset] == destination[i + destinationOffset];
@@ -139,7 +141,7 @@ public class NioByteStringTest extends TestCase {
 
     try {
       // Copy one too many bytes
-      TEST_STRING.copyTo(destination, TEST_STRING.size() + 1 - length,
+      testString.copyTo(destination, testString.size() + 1 - length,
           destinationOffset, length);
       fail("Should have thrown an exception when copying too many bytes of a "
           + CLASSNAME);
@@ -149,7 +151,7 @@ public class NioByteStringTest extends TestCase {
 
     try {
       // Copy with illegal negative sourceOffset
-      TEST_STRING.copyTo(destination, -1, destinationOffset, length);
+      testString.copyTo(destination, -1, destinationOffset, length);
       fail("Should have thrown an exception when given a negative sourceOffset in "
           + CLASSNAME);
     } catch (IndexOutOfBoundsException expected) {
@@ -158,7 +160,7 @@ public class NioByteStringTest extends TestCase {
 
     try {
       // Copy with illegal negative destinationOffset
-      TEST_STRING.copyTo(destination, 0, -1, length);
+      testString.copyTo(destination, 0, -1, length);
       fail("Should have thrown an exception when given a negative destinationOffset in "
           + CLASSNAME);
     } catch (IndexOutOfBoundsException expected) {
@@ -167,7 +169,7 @@ public class NioByteStringTest extends TestCase {
 
     try {
       // Copy with illegal negative size
-      TEST_STRING.copyTo(destination, 0, 0, -1);
+      testString.copyTo(destination, 0, 0, -1);
       fail("Should have thrown an exception when given a negative size in "
           + CLASSNAME);
     } catch (IndexOutOfBoundsException expected) {
@@ -176,7 +178,7 @@ public class NioByteStringTest extends TestCase {
 
     try {
       // Copy with illegal too-large sourceOffset
-      TEST_STRING.copyTo(destination, 2 * TEST_STRING.size(), 0, length);
+      testString.copyTo(destination, 2 * testString.size(), 0, length);
       fail("Should have thrown an exception when the destinationOffset is too large in "
           + CLASSNAME);
     } catch (IndexOutOfBoundsException expected) {
@@ -185,7 +187,7 @@ public class NioByteStringTest extends TestCase {
 
     try {
       // Copy with illegal too-large destinationOffset
-      TEST_STRING.copyTo(destination, 0, 2 * destination.length, length);
+      testString.copyTo(destination, 0, 2 * destination.length, length);
       fail("Should have thrown an exception when the destinationOffset is too large in "
           + CLASSNAME);
     } catch (IndexOutOfBoundsException expected) {
@@ -196,21 +198,21 @@ public class NioByteStringTest extends TestCase {
   public void testCopyTo_ByteBuffer() {
     // Same length.
     ByteBuffer myBuffer = ByteBuffer.allocate(BYTES.length);
-    TEST_STRING.copyTo(myBuffer);
+    testString.copyTo(myBuffer);
     myBuffer.flip();
     assertEquals(CLASSNAME + ".copyTo(ByteBuffer) must give back the same bytes",
-        BUFFER, myBuffer);
+        backingBuffer, myBuffer);
 
     // Target buffer bigger than required.
-    myBuffer = ByteBuffer.allocate(TEST_STRING.size() + 1);
-    TEST_STRING.copyTo(myBuffer);
+    myBuffer = ByteBuffer.allocate(testString.size() + 1);
+    testString.copyTo(myBuffer);
     myBuffer.flip();
-    assertEquals(BUFFER, myBuffer);
+    assertEquals(backingBuffer, myBuffer);
 
     // Target buffer has no space.
     myBuffer = ByteBuffer.allocate(0);
     try {
-      TEST_STRING.copyTo(myBuffer);
+      testString.copyTo(myBuffer);
       fail("Should have thrown an exception when target ByteBuffer has insufficient capacity");
     } catch (BufferOverflowException e) {
       // Expected.
@@ -219,7 +221,7 @@ public class NioByteStringTest extends TestCase {
     // Target buffer too small.
     myBuffer = ByteBuffer.allocate(1);
     try {
-      TEST_STRING.copyTo(myBuffer);
+      testString.copyTo(myBuffer);
       fail("Should have thrown an exception when target ByteBuffer has insufficient capacity");
     } catch (BufferOverflowException e) {
       // Expected.
@@ -227,26 +229,26 @@ public class NioByteStringTest extends TestCase {
   }
 
   public void testMarkSupported() {
-    InputStream stream = TEST_STRING.newInput();
+    InputStream stream = testString.newInput();
     assertTrue(CLASSNAME + ".newInput() must support marking", stream.markSupported());
   }
 
   public void testMarkAndReset() throws IOException {
-    int fraction = TEST_STRING.size() / 3;
+    int fraction = testString.size() / 3;
 
-    InputStream stream = TEST_STRING.newInput();
-    stream.mark(TEST_STRING.size()); // First, mark() the end.
+    InputStream stream = testString.newInput();
+    stream.mark(testString.size()); // First, mark() the end.
 
     skipFully(stream, fraction); // Skip a large fraction, but not all.
     assertEquals(
         CLASSNAME + ": after skipping to the 'middle', half the bytes are available",
-        (TEST_STRING.size() - fraction), stream.available());
+        (testString.size() - fraction), stream.available());
     stream.reset();
     assertEquals(
         CLASSNAME + ": after resetting, all bytes are available",
-        TEST_STRING.size(), stream.available());
+        testString.size(), stream.available());
 
-    skipFully(stream, TEST_STRING.size()); // Skip to the end.
+    skipFully(stream, testString.size()); // Skip to the end.
     assertEquals(
         CLASSNAME + ": after skipping to the end, no more bytes are available",
         0, stream.available());
@@ -284,7 +286,7 @@ public class NioByteStringTest extends TestCase {
   }
 
   public void testAsReadOnlyByteBuffer() {
-    ByteBuffer byteBuffer = TEST_STRING.asReadOnlyByteBuffer();
+    ByteBuffer byteBuffer = testString.asReadOnlyByteBuffer();
     byte[] roundTripBytes = new byte[BYTES.length];
     assertTrue(byteBuffer.remaining() == BYTES.length);
     assertTrue(byteBuffer.isReadOnly());
@@ -294,7 +296,7 @@ public class NioByteStringTest extends TestCase {
   }
 
   public void testAsReadOnlyByteBufferList() {
-    List<ByteBuffer> byteBuffers = TEST_STRING.asReadOnlyByteBufferList();
+    List<ByteBuffer> byteBuffers = testString.asReadOnlyByteBufferList();
     int bytesSeen = 0;
     byte[] roundTripBytes = new byte[BYTES.length];
     for (ByteBuffer byteBuffer : byteBuffers) {
@@ -310,25 +312,98 @@ public class NioByteStringTest extends TestCase {
   }
 
   public void testToByteArray() {
-    byte[] roundTripBytes = TEST_STRING.toByteArray();
+    byte[] roundTripBytes = testString.toByteArray();
     assertTrue(CLASSNAME + ".toByteArray() must give back the same bytes",
         Arrays.equals(BYTES, roundTripBytes));
   }
 
   public void testWriteTo() throws IOException {
     ByteArrayOutputStream bos = new ByteArrayOutputStream();
-    TEST_STRING.writeTo(bos);
+    testString.writeTo(bos);
     byte[] roundTripBytes = bos.toByteArray();
     assertTrue(CLASSNAME + ".writeTo() must give back the same bytes",
         Arrays.equals(BYTES, roundTripBytes));
   }
 
+  public void testWriteToShouldNotExposeInternalBufferToOutputStream() throws IOException {
+    OutputStream os = new OutputStream() {
+      @Override
+      public void write(byte[] b, int off, int len) {
+        Arrays.fill(b, off, off + len, (byte) 0);
+      }
+
+      @Override
+      public void write(int b) {
+        throw new UnsupportedOperationException();
+      }
+    };
+
+    byte[] original = Arrays.copyOf(BYTES, BYTES.length);
+    testString.writeTo(os);
+    assertTrue(CLASSNAME + ".writeTo() must NOT grant access to underlying buffer",
+        Arrays.equals(original, BYTES));
+  }
+
+  public void testWriteToInternalShouldExposeInternalBufferToOutputStream() throws IOException {
+    OutputStream os = new OutputStream() {
+      @Override
+      public void write(byte[] b, int off, int len) {
+        Arrays.fill(b, off, off + len, (byte) 0);
+      }
+
+      @Override
+      public void write(int b) {
+        throw new UnsupportedOperationException();
+      }
+    };
+
+    testString.writeToInternal(os, 0, testString.size());
+    byte[] allZeros = new byte[testString.size()];
+    assertTrue(CLASSNAME + ".writeToInternal() must grant access to underlying buffer",
+        Arrays.equals(allZeros, backingBuffer.array()));
+  }
+
+  public void testWriteToShouldExposeInternalBufferToByteOutput() throws IOException {
+    ByteOutput out = new ByteOutput() {
+      @Override
+      public void write(byte value) throws IOException {
+        throw new UnsupportedOperationException();
+      }
+
+      @Override
+      public void write(byte[] value, int offset, int length) throws IOException {
+        throw new UnsupportedOperationException();
+      }
+
+      @Override
+      public void writeLazy(byte[] value, int offset, int length) throws IOException {
+        throw new UnsupportedOperationException();
+      }
+
+      @Override
+      public void write(ByteBuffer value) throws IOException {
+        throw new UnsupportedOperationException();
+      }
+
+      @Override
+      public void writeLazy(ByteBuffer value) throws IOException {
+        Arrays.fill(value.array(), value.arrayOffset(), value.arrayOffset() + value.limit(),
+            (byte) 0);
+      }
+    };
+
+    testString.writeTo(out);
+    byte[] allZeros = new byte[testString.size()];
+    assertTrue(CLASSNAME + ".writeTo() must grant access to underlying buffer",
+        Arrays.equals(allZeros, backingBuffer.array()));
+  }
+
   public void testNewOutput() throws IOException {
     ByteArrayOutputStream bos = new ByteArrayOutputStream();
     ByteString.Output output = ByteString.newOutput();
-    TEST_STRING.writeTo(output);
+    testString.writeTo(output);
     assertEquals("Output Size returns correct result",
-        output.size(), TEST_STRING.size());
+        output.size(), testString.size());
     output.writeTo(bos);
     assertTrue("Output.writeTo() must give back the same bytes",
         Arrays.equals(BYTES, bos.toByteArray()));
@@ -336,7 +411,7 @@ public class NioByteStringTest extends TestCase {
     // write the output stream to itself! This should cause it to double
     output.writeTo(output);
     assertEquals("Writing an output stream to itself is successful",
-        TEST_STRING.concat(TEST_STRING), output.toByteString());
+        testString.concat(testString), output.toByteString());
 
     output.reset();
     assertEquals("Output.reset() resets the output", 0, output.size());
@@ -373,7 +448,7 @@ public class NioByteStringTest extends TestCase {
     }
 
     try {
-      TEST_STRING.toString("invalid");
+      testString.toString("invalid");
       fail("Should have thrown an exception.");
     } catch (UnsupportedEncodingException expected) {
       // This is success
@@ -381,36 +456,36 @@ public class NioByteStringTest extends TestCase {
   }
 
   public void testEquals() {
-    assertEquals(CLASSNAME + " must not equal null", false, TEST_STRING.equals(null));
-    assertEquals(CLASSNAME + " must equal self", TEST_STRING, TEST_STRING);
+    assertEquals(CLASSNAME + " must not equal null", false, testString.equals(null));
+    assertEquals(CLASSNAME + " must equal self", testString, testString);
     assertFalse(CLASSNAME + " must not equal the empty string",
-        TEST_STRING.equals(EMPTY));
+        testString.equals(EMPTY));
     assertEquals(CLASSNAME + " empty strings must be equal",
-        EMPTY, TEST_STRING.substring(55, 55));
+        EMPTY, testString.substring(55, 55));
     assertEquals(CLASSNAME + " must equal another string with the same value",
-        TEST_STRING, new NioByteString(BUFFER));
+        testString, new NioByteString(backingBuffer));
 
     byte[] mungedBytes = mungedBytes();
     assertFalse(CLASSNAME + " must not equal every string with the same length",
-        TEST_STRING.equals(new NioByteString(ByteBuffer.wrap(mungedBytes))));
+        testString.equals(new NioByteString(ByteBuffer.wrap(mungedBytes))));
   }
 
   public void testEqualsLiteralByteString() {
     ByteString literal = ByteString.copyFrom(BYTES);
     assertEquals(CLASSNAME + " must equal LiteralByteString with same value", literal,
-        TEST_STRING);
-    assertEquals(CLASSNAME + " must equal LiteralByteString with same value", TEST_STRING,
+        testString);
+    assertEquals(CLASSNAME + " must equal LiteralByteString with same value", testString,
         literal);
     assertFalse(CLASSNAME + " must not equal the empty string",
-        TEST_STRING.equals(ByteString.EMPTY));
+        testString.equals(ByteString.EMPTY));
     assertEquals(CLASSNAME + " empty strings must be equal",
-        ByteString.EMPTY, TEST_STRING.substring(55, 55));
+        ByteString.EMPTY, testString.substring(55, 55));
 
     literal = ByteString.copyFrom(mungedBytes());
     assertFalse(CLASSNAME + " must not equal every LiteralByteString with the same length",
-        TEST_STRING.equals(literal));
+        testString.equals(literal));
     assertFalse(CLASSNAME + " must not equal every LiteralByteString with the same length",
-        literal.equals(TEST_STRING));
+        literal.equals(testString));
   }
 
   public void testEqualsRopeByteString() {
@@ -419,22 +494,22 @@ public class NioByteStringTest extends TestCase {
     ByteString rope = p1.concat(p2);
 
     assertEquals(CLASSNAME + " must equal RopeByteString with same value", rope,
-        TEST_STRING);
-    assertEquals(CLASSNAME + " must equal RopeByteString with same value", TEST_STRING,
+        testString);
+    assertEquals(CLASSNAME + " must equal RopeByteString with same value", testString,
         rope);
     assertFalse(CLASSNAME + " must not equal the empty string",
-        TEST_STRING.equals(ByteString.EMPTY.concat(ByteString.EMPTY)));
+        testString.equals(ByteString.EMPTY.concat(ByteString.EMPTY)));
     assertEquals(CLASSNAME + " empty strings must be equal",
-        ByteString.EMPTY.concat(ByteString.EMPTY), TEST_STRING.substring(55, 55));
+        ByteString.EMPTY.concat(ByteString.EMPTY), testString.substring(55, 55));
 
     byte[] mungedBytes = mungedBytes();
     p1 = ByteString.copyFrom(mungedBytes, 0, 5);
     p2 = ByteString.copyFrom(mungedBytes, 5, mungedBytes.length - 5);
     rope = p1.concat(p2);
     assertFalse(CLASSNAME + " must not equal every RopeByteString with the same length",
-        TEST_STRING.equals(rope));
+        testString.equals(rope));
     assertFalse(CLASSNAME + " must not equal every RopeByteString with the same length",
-        rope.equals(TEST_STRING));
+        rope.equals(testString));
   }
 
   private byte[] mungedBytes() {
@@ -445,12 +520,12 @@ public class NioByteStringTest extends TestCase {
   }
 
   public void testHashCode() {
-    int hash = TEST_STRING.hashCode();
+    int hash = testString.hashCode();
     assertEquals(CLASSNAME + " must have expected hashCode", EXPECTED_HASH, hash);
   }
 
   public void testPeekCachedHashCode() {
-    ByteString newString = new NioByteString(BUFFER);
+    ByteString newString = new NioByteString(backingBuffer);
     assertEquals(CLASSNAME + ".peekCachedHashCode() should return zero at first", 0,
         newString.peekCachedHashCode());
     newString.hashCode();
@@ -461,15 +536,15 @@ public class NioByteStringTest extends TestCase {
   public void testPartialHash() {
     // partialHash() is more strenuously tested elsewhere by testing hashes of substrings.
     // This test would fail if the expected hash were 1.  It's not.
-    int hash = TEST_STRING.partialHash(TEST_STRING.size(), 0, TEST_STRING.size());
+    int hash = testString.partialHash(testString.size(), 0, testString.size());
     assertEquals(CLASSNAME + ".partialHash() must yield expected hashCode",
         EXPECTED_HASH, hash);
   }
 
   public void testNewInput() throws IOException {
-    InputStream input = TEST_STRING.newInput();
+    InputStream input = testString.newInput();
     assertEquals("InputStream.available() returns correct value",
-        TEST_STRING.size(), input.available());
+        testString.size(), input.available());
     boolean stillEqual = true;
     for (byte referenceByte : BYTES) {
       int expectedInt = (referenceByte & 0xFF);
@@ -482,8 +557,8 @@ public class NioByteStringTest extends TestCase {
   }
 
   public void testNewInput_skip() throws IOException {
-    InputStream input = TEST_STRING.newInput();
-    int stringSize = TEST_STRING.size();
+    InputStream input = testString.newInput();
+    int stringSize = testString.size();
     int nearEndIndex = stringSize * 2 / 3;
     long skipped1 = input.skip(nearEndIndex);
     assertEquals("InputStream.skip()", skipped1, nearEndIndex);
@@ -492,7 +567,7 @@ public class NioByteStringTest extends TestCase {
     assertTrue("InputStream.mark() is available", input.markSupported());
     input.mark(0);
     assertEquals("InputStream.skip(), read()",
-        TEST_STRING.byteAt(nearEndIndex) & 0xFF, input.read());
+        testString.byteAt(nearEndIndex) & 0xFF, input.read());
     assertEquals("InputStream.available()",
         stringSize - skipped1 - 1, input.available());
     long skipped2 = input.skip(stringSize);
@@ -504,11 +579,11 @@ public class NioByteStringTest extends TestCase {
     assertEquals("InputStream.reset() succeded",
         stringSize - skipped1, input.available());
     assertEquals("InputStream.reset(), read()",
-        TEST_STRING.byteAt(nearEndIndex) & 0xFF, input.read());
+        testString.byteAt(nearEndIndex) & 0xFF, input.read());
   }
 
   public void testNewCodedInput() throws IOException {
-    CodedInputStream cis = TEST_STRING.newCodedInput();
+    CodedInputStream cis = testString.newCodedInput();
     byte[] roundTripBytes = cis.readRawBytes(BYTES.length);
     assertTrue(CLASSNAME + " must give the same bytes back from the CodedInputStream",
         Arrays.equals(BYTES, roundTripBytes));
@@ -521,22 +596,22 @@ public class NioByteStringTest extends TestCase {
    */
   public void testConcat_empty() {
     assertSame(CLASSNAME + " concatenated with empty must give " + CLASSNAME,
-        TEST_STRING.concat(EMPTY), TEST_STRING);
+        testString.concat(EMPTY), testString);
     assertSame("empty concatenated with " + CLASSNAME + " must give " + CLASSNAME,
-        EMPTY.concat(TEST_STRING), TEST_STRING);
+        EMPTY.concat(testString), testString);
   }
 
   public void testJavaSerialization() throws Exception {
     ByteArrayOutputStream out = new ByteArrayOutputStream();
     ObjectOutputStream oos = new ObjectOutputStream(out);
-    oos.writeObject(TEST_STRING);
+    oos.writeObject(testString);
     oos.close();
     byte[] pickled = out.toByteArray();
     InputStream in = new ByteArrayInputStream(pickled);
     ObjectInputStream ois = new ObjectInputStream(in);
     Object o = ois.readObject();
     assertTrue("Didn't get a ByteString back", o instanceof ByteString);
-    assertEquals("Should get an equal ByteString back", TEST_STRING, o);
+    assertEquals("Should get an equal ByteString back", testString, o);
   }
 
   private static ByteString forString(String str) {
diff --git a/java/core/src/test/java/com/google/protobuf/ParseExceptionsTest.java b/java/core/src/test/java/com/google/protobuf/ParseExceptionsTest.java
index 37fa242d..bf1f1d71 100644
--- a/java/core/src/test/java/com/google/protobuf/ParseExceptionsTest.java
+++ b/java/core/src/test/java/com/google/protobuf/ParseExceptionsTest.java
@@ -1,17 +1,51 @@
+// 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 org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
 import com.google.protobuf.DescriptorProtos.DescriptorProto;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.FilterInputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import org.junit.Test;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
 
 /**
  * Tests the exceptions thrown when parsing from a stream. The methods on the {@link Parser}
@@ -22,6 +56,7 @@ import static org.junit.Assert.fail;
  *
  * @author jh@squareup.com (Joshua Humphries)
  */
+@RunWith(JUnit4.class)
 public class ParseExceptionsTest {
 
   private interface ParseTester {
@@ -46,116 +81,143 @@ public class ParseExceptionsTest {
 
   @Test public void message_parseFrom_InputStream() {
     setup();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        return DescriptorProto.parseFrom(in);
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            return DescriptorProto.parseFrom(in);
+          }
+        });
   }
 
   @Test public void message_parseFrom_InputStreamAndExtensionRegistry() {
     setup();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        return DescriptorProto.parseFrom(in, ExtensionRegistry.newInstance());
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            return DescriptorProto.parseFrom(in, ExtensionRegistry.newInstance());
+          }
+        });
   }
 
   @Test public void message_parseFrom_CodedInputStream() {
     setup();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        return DescriptorProto.parseFrom(CodedInputStream.newInstance(in));
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            return DescriptorProto.parseFrom(CodedInputStream.newInstance(in));
+          }
+        });
   }
 
   @Test public void message_parseFrom_CodedInputStreamAndExtensionRegistry() {
     setup();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        return DescriptorProto.parseFrom(CodedInputStream.newInstance(in),
-            ExtensionRegistry.newInstance());
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            return DescriptorProto.parseFrom(
+                CodedInputStream.newInstance(in), ExtensionRegistry.newInstance());
+          }
+        });
   }
 
   @Test public void message_parseDelimitedFrom_InputStream() {
     setupDelimited();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        return DescriptorProto.parseDelimitedFrom(in);
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            return DescriptorProto.parseDelimitedFrom(in);
+          }
+        });
   }
 
   @Test public void message_parseDelimitedFrom_InputStreamAndExtensionRegistry() {
     setupDelimited();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        return DescriptorProto.parseDelimitedFrom(in, ExtensionRegistry.newInstance());
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            return DescriptorProto.parseDelimitedFrom(in, ExtensionRegistry.newInstance());
+          }
+        });
   }
 
   @Test public void messageBuilder_mergeFrom_InputStream() {
     setup();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        return DescriptorProto.newBuilder().mergeFrom(in).build();
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            return DescriptorProto.newBuilder().mergeFrom(in).build();
+          }
+        });
   }
 
   @Test public void messageBuilder_mergeFrom_InputStreamAndExtensionRegistry() {
     setup();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        return DescriptorProto.newBuilder().mergeFrom(in, ExtensionRegistry.newInstance()).build();
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            return DescriptorProto.newBuilder()
+                .mergeFrom(in, ExtensionRegistry.newInstance())
+                .build();
+          }
+        });
   }
 
   @Test public void messageBuilder_mergeFrom_CodedInputStream() {
     setup();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        return DescriptorProto.newBuilder().mergeFrom(CodedInputStream.newInstance(in)).build();
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            return DescriptorProto.newBuilder().mergeFrom(CodedInputStream.newInstance(in)).build();
+          }
+        });
   }
 
   @Test public void messageBuilder_mergeFrom_CodedInputStreamAndExtensionRegistry() {
     setup();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        return DescriptorProto.newBuilder()
-            .mergeFrom(CodedInputStream.newInstance(in), ExtensionRegistry.newInstance()).build();
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            return DescriptorProto.newBuilder()
+                .mergeFrom(CodedInputStream.newInstance(in), ExtensionRegistry.newInstance())
+                .build();
+          }
+        });
   }
 
   @Test public void messageBuilder_mergeDelimitedFrom_InputStream() {
     setupDelimited();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        DescriptorProto.Builder builder = DescriptorProto.newBuilder();
-        builder.mergeDelimitedFrom(in);
-        return builder.build();
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            DescriptorProto.Builder builder = DescriptorProto.newBuilder();
+            builder.mergeDelimitedFrom(in);
+            return builder.build();
+          }
+        });
   }
 
   @Test public void messageBuilder_mergeDelimitedFrom_InputStreamAndExtensionRegistry() {
     setupDelimited();
-    verifyExceptions(new ParseTester() {
-      public DescriptorProto parse(InputStream in) throws IOException {
-        DescriptorProto.Builder builder = DescriptorProto.newBuilder();
-        builder.mergeDelimitedFrom(in, ExtensionRegistry.newInstance());
-        return builder.build();
-      }
-    });
+    verifyExceptions(
+        new ParseTester() {
+          @Override
+          public DescriptorProto parse(InputStream in) throws IOException {
+            DescriptorProto.Builder builder = DescriptorProto.newBuilder();
+            builder.mergeDelimitedFrom(in, ExtensionRegistry.newInstance());
+            return builder.build();
+          }
+        });
   }
 
   private void verifyExceptions(ParseTester parseTester) {
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 5a92bacf..9d4b6b94 100644
--- a/java/core/src/test/java/com/google/protobuf/ParserTest.java
+++ b/java/core/src/test/java/com/google/protobuf/ParserTest.java
@@ -33,15 +33,15 @@ package com.google.protobuf;
 import com.google.protobuf.UnittestLite.TestAllTypesLite;
 import com.google.protobuf.UnittestLite.TestPackedExtensionsLite;
 import com.google.protobuf.UnittestLite.TestParsingMergeLite;
+import protobuf_unittest.UnittestOptimizeFor;
 import protobuf_unittest.UnittestOptimizeFor.TestOptimizedForSize;
 import protobuf_unittest.UnittestOptimizeFor.TestRequiredOptimizedForSize;
-import protobuf_unittest.UnittestOptimizeFor;
+import protobuf_unittest.UnittestProto;
 import protobuf_unittest.UnittestProto.ForeignMessage;
 import protobuf_unittest.UnittestProto.TestAllTypes;
 import protobuf_unittest.UnittestProto.TestEmptyMessage;
 import protobuf_unittest.UnittestProto.TestParsingMerge;
 import protobuf_unittest.UnittestProto.TestRequired;
-import protobuf_unittest.UnittestProto;
 
 import junit.framework.TestCase;
 
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 ff980d66..7f3439d0 100644
--- a/java/core/src/test/java/com/google/protobuf/ServiceTest.java
+++ b/java/core/src/test/java/com/google/protobuf/ServiceTest.java
@@ -35,22 +35,22 @@ import com.google.protobuf.Descriptors.MethodDescriptor;
 import google.protobuf.no_generic_services_test.UnittestNoGenericServices;
 import protobuf_unittest.MessageWithNoOuter;
 import protobuf_unittest.ServiceWithNoOuter;
-import protobuf_unittest.UnittestProto.TestAllTypes;
-import protobuf_unittest.UnittestProto.TestService;
-import protobuf_unittest.UnittestProto.FooRequest;
-import protobuf_unittest.UnittestProto.FooResponse;
 import protobuf_unittest.UnittestProto.BarRequest;
 import protobuf_unittest.UnittestProto.BarResponse;
+import protobuf_unittest.UnittestProto.FooRequest;
+import protobuf_unittest.UnittestProto.FooResponse;
+import protobuf_unittest.UnittestProto.TestAllTypes;
+import protobuf_unittest.UnittestProto.TestService;
+
+import junit.framework.TestCase;
 
 import org.easymock.classextension.EasyMock;
-import org.easymock.classextension.IMocksControl;
 import org.easymock.IArgumentMatcher;
+import org.easymock.classextension.IMocksControl;
 
 import java.util.HashSet;
 import java.util.Set;
 
-import junit.framework.TestCase;
-
 /**
  * Tests services and stubs.
  *
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 01acb884..53d65428 100644
--- a/java/core/src/test/java/com/google/protobuf/TestUtil.java
+++ b/java/core/src/test/java/com/google/protobuf/TestUtil.java
@@ -30,205 +30,207 @@
 
 package com.google.protobuf;
 
-import protobuf_unittest.UnittestProto;
-import com.google.protobuf.UnittestLite;
-
+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 static protobuf_unittest.UnittestProto.OptionalGroup_extension;
+import static protobuf_unittest.UnittestProto.RepeatedGroup_extension;
+import static protobuf_unittest.UnittestProto.defaultBoolExtension;
+import static protobuf_unittest.UnittestProto.defaultBytesExtension;
+import static protobuf_unittest.UnittestProto.defaultCordExtension;
+import static protobuf_unittest.UnittestProto.defaultDoubleExtension;
+import static protobuf_unittest.UnittestProto.defaultFixed32Extension;
+import static protobuf_unittest.UnittestProto.defaultFixed64Extension;
+import static protobuf_unittest.UnittestProto.defaultFloatExtension;
+import static protobuf_unittest.UnittestProto.defaultForeignEnumExtension;
+import static protobuf_unittest.UnittestProto.defaultImportEnumExtension;
 // The static imports are to avoid 100+ char lines.  The following is roughly equivalent to
 // import static protobuf_unittest.UnittestProto.*;
 import static protobuf_unittest.UnittestProto.defaultInt32Extension;
 import static protobuf_unittest.UnittestProto.defaultInt64Extension;
-import static protobuf_unittest.UnittestProto.defaultUint32Extension;
-import static protobuf_unittest.UnittestProto.defaultUint64Extension;
-import static protobuf_unittest.UnittestProto.defaultSint32Extension;
-import static protobuf_unittest.UnittestProto.defaultSint64Extension;
-import static protobuf_unittest.UnittestProto.defaultFixed32Extension;
-import static protobuf_unittest.UnittestProto.defaultFixed64Extension;
+import static protobuf_unittest.UnittestProto.defaultNestedEnumExtension;
 import static protobuf_unittest.UnittestProto.defaultSfixed32Extension;
 import static protobuf_unittest.UnittestProto.defaultSfixed64Extension;
-import static protobuf_unittest.UnittestProto.defaultFloatExtension;
-import static protobuf_unittest.UnittestProto.defaultDoubleExtension;
-import static protobuf_unittest.UnittestProto.defaultBoolExtension;
+import static protobuf_unittest.UnittestProto.defaultSint32Extension;
+import static protobuf_unittest.UnittestProto.defaultSint64Extension;
 import static protobuf_unittest.UnittestProto.defaultStringExtension;
-import static protobuf_unittest.UnittestProto.defaultBytesExtension;
-import static protobuf_unittest.UnittestProto.defaultNestedEnumExtension;
-import static protobuf_unittest.UnittestProto.defaultForeignEnumExtension;
-import static protobuf_unittest.UnittestProto.defaultImportEnumExtension;
 import static protobuf_unittest.UnittestProto.defaultStringPieceExtension;
-import static protobuf_unittest.UnittestProto.defaultCordExtension;
-
-import static protobuf_unittest.UnittestProto.oneofUint32Extension;
+import static protobuf_unittest.UnittestProto.defaultUint32Extension;
+import static protobuf_unittest.UnittestProto.defaultUint64Extension;
+import static protobuf_unittest.UnittestProto.oneofBytesExtension;
 import static protobuf_unittest.UnittestProto.oneofNestedMessageExtension;
 import static protobuf_unittest.UnittestProto.oneofStringExtension;
-import static protobuf_unittest.UnittestProto.oneofBytesExtension;
-
-import static protobuf_unittest.UnittestProto.optionalInt32Extension;
-import static protobuf_unittest.UnittestProto.optionalInt64Extension;
-import static protobuf_unittest.UnittestProto.optionalUint32Extension;
-import static protobuf_unittest.UnittestProto.optionalUint64Extension;
-import static protobuf_unittest.UnittestProto.optionalSint32Extension;
-import static protobuf_unittest.UnittestProto.optionalSint64Extension;
-import static protobuf_unittest.UnittestProto.optionalFixed32Extension;
-import static protobuf_unittest.UnittestProto.optionalFixed64Extension;
-import static protobuf_unittest.UnittestProto.optionalSfixed32Extension;
-import static protobuf_unittest.UnittestProto.optionalSfixed64Extension;
-import static protobuf_unittest.UnittestProto.optionalFloatExtension;
-import static protobuf_unittest.UnittestProto.optionalDoubleExtension;
+import static protobuf_unittest.UnittestProto.oneofUint32Extension;
 import static protobuf_unittest.UnittestProto.optionalBoolExtension;
-import static protobuf_unittest.UnittestProto.optionalStringExtension;
 import static protobuf_unittest.UnittestProto.optionalBytesExtension;
-import static protobuf_unittest.UnittestProto.optionalGroupExtension;
 import static protobuf_unittest.UnittestProto.optionalCordExtension;
+import static protobuf_unittest.UnittestProto.optionalDoubleExtension;
+import static protobuf_unittest.UnittestProto.optionalFixed32Extension;
+import static protobuf_unittest.UnittestProto.optionalFixed64Extension;
+import static protobuf_unittest.UnittestProto.optionalFloatExtension;
 import static protobuf_unittest.UnittestProto.optionalForeignEnumExtension;
 import static protobuf_unittest.UnittestProto.optionalForeignMessageExtension;
+import static protobuf_unittest.UnittestProto.optionalGroupExtension;
 import static protobuf_unittest.UnittestProto.optionalImportEnumExtension;
 import static protobuf_unittest.UnittestProto.optionalImportMessageExtension;
+import static protobuf_unittest.UnittestProto.optionalInt32Extension;
+import static protobuf_unittest.UnittestProto.optionalInt64Extension;
+import static protobuf_unittest.UnittestProto.optionalLazyMessageExtension;
 import static protobuf_unittest.UnittestProto.optionalNestedEnumExtension;
 import static protobuf_unittest.UnittestProto.optionalNestedMessageExtension;
 import static protobuf_unittest.UnittestProto.optionalPublicImportMessageExtension;
-import static protobuf_unittest.UnittestProto.optionalLazyMessageExtension;
+import static protobuf_unittest.UnittestProto.optionalSfixed32Extension;
+import static protobuf_unittest.UnittestProto.optionalSfixed64Extension;
+import static protobuf_unittest.UnittestProto.optionalSint32Extension;
+import static protobuf_unittest.UnittestProto.optionalSint64Extension;
+import static protobuf_unittest.UnittestProto.optionalStringExtension;
 import static protobuf_unittest.UnittestProto.optionalStringPieceExtension;
-
-import static protobuf_unittest.UnittestProto.repeatedInt32Extension;
-import static protobuf_unittest.UnittestProto.repeatedInt64Extension;
-import static protobuf_unittest.UnittestProto.repeatedUint32Extension;
-import static protobuf_unittest.UnittestProto.repeatedUint64Extension;
-import static protobuf_unittest.UnittestProto.repeatedSint32Extension;
-import static protobuf_unittest.UnittestProto.repeatedSint64Extension;
+import static protobuf_unittest.UnittestProto.optionalUint32Extension;
+import static protobuf_unittest.UnittestProto.optionalUint64Extension;
+import static protobuf_unittest.UnittestProto.packedBoolExtension;
+import static protobuf_unittest.UnittestProto.packedDoubleExtension;
+import static protobuf_unittest.UnittestProto.packedEnumExtension;
+import static protobuf_unittest.UnittestProto.packedFixed32Extension;
+import static protobuf_unittest.UnittestProto.packedFixed64Extension;
+import static protobuf_unittest.UnittestProto.packedFloatExtension;
+import static protobuf_unittest.UnittestProto.packedInt32Extension;
+import static protobuf_unittest.UnittestProto.packedInt64Extension;
+import static protobuf_unittest.UnittestProto.packedSfixed32Extension;
+import static protobuf_unittest.UnittestProto.packedSfixed64Extension;
+import static protobuf_unittest.UnittestProto.packedSint32Extension;
+import static protobuf_unittest.UnittestProto.packedSint64Extension;
+import static protobuf_unittest.UnittestProto.packedUint32Extension;
+import static protobuf_unittest.UnittestProto.packedUint64Extension;
+import static protobuf_unittest.UnittestProto.repeatedBoolExtension;
+import static protobuf_unittest.UnittestProto.repeatedBytesExtension;
+import static protobuf_unittest.UnittestProto.repeatedCordExtension;
+import static protobuf_unittest.UnittestProto.repeatedDoubleExtension;
 import static protobuf_unittest.UnittestProto.repeatedFixed32Extension;
 import static protobuf_unittest.UnittestProto.repeatedFixed64Extension;
-import static protobuf_unittest.UnittestProto.repeatedSfixed32Extension;
-import static protobuf_unittest.UnittestProto.repeatedSfixed64Extension;
 import static protobuf_unittest.UnittestProto.repeatedFloatExtension;
-import static protobuf_unittest.UnittestProto.repeatedDoubleExtension;
-import static protobuf_unittest.UnittestProto.repeatedBoolExtension;
-import static protobuf_unittest.UnittestProto.repeatedStringExtension;
-import static protobuf_unittest.UnittestProto.repeatedBytesExtension;
-import static protobuf_unittest.UnittestProto.repeatedGroupExtension;
-import static protobuf_unittest.UnittestProto.repeatedNestedMessageExtension;
+import static protobuf_unittest.UnittestProto.repeatedForeignEnumExtension;
 import static protobuf_unittest.UnittestProto.repeatedForeignMessageExtension;
+import static protobuf_unittest.UnittestProto.repeatedGroupExtension;
+import static protobuf_unittest.UnittestProto.repeatedImportEnumExtension;
 import static protobuf_unittest.UnittestProto.repeatedImportMessageExtension;
+import static protobuf_unittest.UnittestProto.repeatedInt32Extension;
+import static protobuf_unittest.UnittestProto.repeatedInt64Extension;
 import static protobuf_unittest.UnittestProto.repeatedLazyMessageExtension;
 import static protobuf_unittest.UnittestProto.repeatedNestedEnumExtension;
-import static protobuf_unittest.UnittestProto.repeatedForeignEnumExtension;
-import static protobuf_unittest.UnittestProto.repeatedImportEnumExtension;
+import static protobuf_unittest.UnittestProto.repeatedNestedMessageExtension;
+import static protobuf_unittest.UnittestProto.repeatedSfixed32Extension;
+import static protobuf_unittest.UnittestProto.repeatedSfixed64Extension;
+import static protobuf_unittest.UnittestProto.repeatedSint32Extension;
+import static protobuf_unittest.UnittestProto.repeatedSint64Extension;
+import static protobuf_unittest.UnittestProto.repeatedStringExtension;
 import static protobuf_unittest.UnittestProto.repeatedStringPieceExtension;
-import static protobuf_unittest.UnittestProto.repeatedCordExtension;
-
-import static protobuf_unittest.UnittestProto.OptionalGroup_extension;
-import static protobuf_unittest.UnittestProto.RepeatedGroup_extension;
-
-import static protobuf_unittest.UnittestProto.packedInt32Extension;
-import static protobuf_unittest.UnittestProto.packedInt64Extension;
-import static protobuf_unittest.UnittestProto.packedUint32Extension;
-import static protobuf_unittest.UnittestProto.packedUint64Extension;
-import static protobuf_unittest.UnittestProto.packedSint32Extension;
-import static protobuf_unittest.UnittestProto.packedSint64Extension;
-import static protobuf_unittest.UnittestProto.packedFixed32Extension;
-import static protobuf_unittest.UnittestProto.packedFixed64Extension;
-import static protobuf_unittest.UnittestProto.packedSfixed32Extension;
-import static protobuf_unittest.UnittestProto.packedSfixed64Extension;
-import static protobuf_unittest.UnittestProto.packedFloatExtension;
-import static protobuf_unittest.UnittestProto.packedDoubleExtension;
-import static protobuf_unittest.UnittestProto.packedBoolExtension;
-import static protobuf_unittest.UnittestProto.packedEnumExtension;
-
-import static com.google.protobuf.UnittestLite.defaultInt32ExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultInt64ExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultUint32ExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultUint64ExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultSint32ExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultSint64ExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultFixed32ExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultFixed64ExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultSfixed32ExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultSfixed64ExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultFloatExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultDoubleExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultBoolExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultStringExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultBytesExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultNestedEnumExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultForeignEnumExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultImportEnumExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultStringPieceExtensionLite;
-import static com.google.protobuf.UnittestLite.defaultCordExtensionLite;
-
-import static com.google.protobuf.UnittestLite.oneofUint32ExtensionLite;
-import static com.google.protobuf.UnittestLite.oneofNestedMessageExtensionLite;
-import static com.google.protobuf.UnittestLite.oneofStringExtensionLite;
-import static com.google.protobuf.UnittestLite.oneofBytesExtensionLite;
-
-import static com.google.protobuf.UnittestLite.optionalInt32ExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalInt64ExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalUint32ExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalUint64ExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalSint32ExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalSint64ExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalFixed32ExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalFixed64ExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalSfixed32ExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalSfixed64ExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalFloatExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalDoubleExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalBoolExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalStringExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalBytesExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalGroupExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalNestedMessageExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalForeignEnumExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalForeignMessageExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalImportEnumExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalImportMessageExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalNestedEnumExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalPublicImportMessageExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalLazyMessageExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalStringPieceExtensionLite;
-import static com.google.protobuf.UnittestLite.optionalCordExtensionLite;
-
-import static com.google.protobuf.UnittestLite.repeatedInt32ExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedInt64ExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedUint32ExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedUint64ExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedSint32ExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedSint64ExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedFixed32ExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedFixed64ExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedSfixed32ExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedSfixed64ExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedFloatExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedDoubleExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedBoolExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedStringExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedBytesExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedGroupExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedNestedMessageExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedForeignMessageExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedImportMessageExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedLazyMessageExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedNestedEnumExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedForeignEnumExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedImportEnumExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedStringPieceExtensionLite;
-import static com.google.protobuf.UnittestLite.repeatedCordExtensionLite;
-
-import static com.google.protobuf.UnittestLite.OptionalGroup_extension_lite;
-import static com.google.protobuf.UnittestLite.RepeatedGroup_extension_lite;
-
-import static com.google.protobuf.UnittestLite.packedInt32ExtensionLite;
-import static com.google.protobuf.UnittestLite.packedInt64ExtensionLite;
-import static com.google.protobuf.UnittestLite.packedUint32ExtensionLite;
-import static com.google.protobuf.UnittestLite.packedUint64ExtensionLite;
-import static com.google.protobuf.UnittestLite.packedSint32ExtensionLite;
-import static com.google.protobuf.UnittestLite.packedSint64ExtensionLite;
-import static com.google.protobuf.UnittestLite.packedFixed32ExtensionLite;
-import static com.google.protobuf.UnittestLite.packedFixed64ExtensionLite;
-import static com.google.protobuf.UnittestLite.packedSfixed32ExtensionLite;
-import static com.google.protobuf.UnittestLite.packedSfixed64ExtensionLite;
-import static com.google.protobuf.UnittestLite.packedFloatExtensionLite;
-import static com.google.protobuf.UnittestLite.packedDoubleExtensionLite;
-import static com.google.protobuf.UnittestLite.packedBoolExtensionLite;
-import static com.google.protobuf.UnittestLite.packedEnumExtensionLite;
+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;
+import com.google.protobuf.test.UnittestImport.ImportEnum;
+import com.google.protobuf.test.UnittestImport.ImportMessage;
+import com.google.protobuf.test.UnittestImportPublic.PublicImportMessage;
+import protobuf_unittest.UnittestProto;
+import protobuf_unittest.UnittestProto.ForeignEnum;
+import protobuf_unittest.UnittestProto.ForeignMessage;
 import protobuf_unittest.UnittestProto.TestAllExtensions;
 import protobuf_unittest.UnittestProto.TestAllExtensionsOrBuilder;
 import protobuf_unittest.UnittestProto.TestAllTypes;
@@ -237,21 +239,6 @@ import protobuf_unittest.UnittestProto.TestOneof2;
 import protobuf_unittest.UnittestProto.TestPackedExtensions;
 import protobuf_unittest.UnittestProto.TestPackedTypes;
 import protobuf_unittest.UnittestProto.TestUnpackedTypes;
-import protobuf_unittest.UnittestProto.ForeignMessage;
-import protobuf_unittest.UnittestProto.ForeignEnum;
-import com.google.protobuf.test.UnittestImport.ImportEnum;
-import com.google.protobuf.test.UnittestImport.ImportMessage;
-import com.google.protobuf.test.UnittestImportPublic.PublicImportMessage;
-
-import com.google.protobuf.UnittestLite.TestAllTypesLite;
-import com.google.protobuf.UnittestLite.TestAllExtensionsLite;
-import com.google.protobuf.UnittestLite.TestAllExtensionsLiteOrBuilder;
-import com.google.protobuf.UnittestLite.TestPackedExtensionsLite;
-import com.google.protobuf.UnittestLite.ForeignMessageLite;
-import com.google.protobuf.UnittestLite.ForeignEnumLite;
-import com.google.protobuf.UnittestImportLite.ImportEnumLite;
-import com.google.protobuf.UnittestImportLite.ImportMessageLite;
-import com.google.protobuf.UnittestImportPublicLite.PublicImportMessageLite;
 
 import junit.framework.Assert;
 
diff --git a/java/core/src/test/java/com/google/protobuf/TextFormatParseInfoTreeTest.java b/java/core/src/test/java/com/google/protobuf/TextFormatParseInfoTreeTest.java
new file mode 100644
index 00000000..e338af21
--- /dev/null
+++ b/java/core/src/test/java/com/google/protobuf/TextFormatParseInfoTreeTest.java
@@ -0,0 +1,182 @@
+// 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 com.google.protobuf.Descriptors.Descriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import protobuf_unittest.UnittestProto.TestAllTypes;
+
+import junit.framework.TestCase;
+
+/**
+ * Test @{link TextFormatParseInfoTree}.
+ */
+public class TextFormatParseInfoTreeTest extends TestCase {
+
+  private static final Descriptor DESCRIPTOR = TestAllTypes.getDescriptor();
+  private static final FieldDescriptor OPTIONAL_INT32 =
+      DESCRIPTOR.findFieldByName("optional_int32");
+  private static final FieldDescriptor OPTIONAL_BOOLEAN =
+      DESCRIPTOR.findFieldByName("optional_boolean");
+  private static final FieldDescriptor REPEATED_INT32 =
+      DESCRIPTOR.findFieldByName("repeated_int32");
+  private static final FieldDescriptor OPTIONAL_NESTED_MESSAGE =
+      DESCRIPTOR.findFieldByName("optional_nested_message");
+  private static final FieldDescriptor REPEATED_NESTED_MESSAGE =
+      DESCRIPTOR.findFieldByName("repeated_nested_message");
+  private static final FieldDescriptor FIELD_BB =
+      TestAllTypes.NestedMessage.getDescriptor().findFieldByName("bb");
+
+  private static final TextFormatParseLocation LOC0 = TextFormatParseLocation.create(1, 2);
+  private static final TextFormatParseLocation LOC1 = TextFormatParseLocation.create(2, 3);
+
+  private TextFormatParseInfoTree.Builder rootBuilder;
+
+  @Override
+  public void setUp() {
+    rootBuilder = TextFormatParseInfoTree.builder();
+  }
+
+  public void testBuildEmptyParseTree() {
+    TextFormatParseInfoTree tree = rootBuilder.build();
+    assertTrue(tree.getLocations(null).isEmpty());
+  }
+
+  public void testGetLocationReturnsSingleLocation() {
+    rootBuilder.setLocation(OPTIONAL_INT32, LOC0);
+    TextFormatParseInfoTree root = rootBuilder.build();
+    assertEquals(LOC0, root.getLocation(OPTIONAL_INT32, 0));
+    assertEquals(1, root.getLocations(OPTIONAL_INT32).size());
+    }
+
+  public void testGetLocationsReturnsNoParseLocationsForUnknownField() {
+    assertTrue(rootBuilder.build().getLocations(OPTIONAL_INT32).isEmpty());
+    rootBuilder.setLocation(OPTIONAL_BOOLEAN, LOC0);
+    TextFormatParseInfoTree root = rootBuilder.build();
+    assertTrue(root.getLocations(OPTIONAL_INT32).isEmpty());
+    assertEquals(LOC0, root.getLocations(OPTIONAL_BOOLEAN).get(0));
+  }
+
+  public void testGetLocationThrowsIllegalArgumentExceptionForUnknownField() {
+    rootBuilder.setLocation(REPEATED_INT32, LOC0);
+    TextFormatParseInfoTree root = rootBuilder.build();
+    try {
+      root.getNestedTree(OPTIONAL_INT32, 0);
+      fail("Did not detect unknown field");
+    } catch (IllegalArgumentException expected) {
+      // pass
+    }
+  }
+
+  public void testGetLocationThrowsIllegalArgumentExceptionForInvalidIndex() {
+    TextFormatParseInfoTree root = rootBuilder.setLocation(OPTIONAL_INT32, LOC0).build();
+    try {
+      root.getLocation(OPTIONAL_INT32, 1);
+      fail("Invalid index not detected");
+    } catch (IllegalArgumentException expected) {
+      // pass
+    }
+    try {
+      root.getLocation(OPTIONAL_INT32, -1);
+      fail("Negative index not detected");
+    } catch (IllegalArgumentException expected) {
+      // pass
+    }
+  }
+
+  public void testGetLocationsReturnsMultipleLocations() {
+    rootBuilder.setLocation(REPEATED_INT32, LOC0);
+    rootBuilder.setLocation(REPEATED_INT32, LOC1);
+    TextFormatParseInfoTree root = rootBuilder.build();
+    assertEquals(LOC0, root.getLocation(REPEATED_INT32, 0));
+    assertEquals(LOC1, root.getLocation(REPEATED_INT32, 1));
+    assertEquals(2, root.getLocations(REPEATED_INT32).size());
+  }
+
+  public void testGetNestedTreeThrowsIllegalArgumentExceptionForUnknownField() {
+    rootBuilder.setLocation(REPEATED_INT32, LOC0);
+    TextFormatParseInfoTree root = rootBuilder.build();
+    try {
+      root.getNestedTree(OPTIONAL_NESTED_MESSAGE, 0);
+      fail("Did not detect unknown field");
+    } catch (IllegalArgumentException expected) {
+      // pass
+    }
+  }
+
+  public void testGetNestedTreesReturnsNoParseInfoTreesForUnknownField() {
+    rootBuilder.setLocation(REPEATED_INT32, LOC0);
+    TextFormatParseInfoTree root = rootBuilder.build();
+    assertTrue(root.getNestedTrees(OPTIONAL_NESTED_MESSAGE).isEmpty());
+  }
+
+  public void testGetNestedTreeThrowsIllegalArgumentExceptionForInvalidIndex() {
+    rootBuilder.setLocation(REPEATED_INT32, LOC0);
+    rootBuilder.getBuilderForSubMessageField(OPTIONAL_NESTED_MESSAGE);
+    TextFormatParseInfoTree root = rootBuilder.build();
+    try {
+      root.getNestedTree(OPTIONAL_NESTED_MESSAGE, 1);
+      fail("Submessage index that is too large not detected");
+    } catch (IllegalArgumentException expected) {
+      // pass
+    }
+    try {
+      rootBuilder.build().getNestedTree(OPTIONAL_NESTED_MESSAGE, -1);
+      fail("Invalid submessage index (-1) not detected");
+    } catch (IllegalArgumentException expected) {
+      // pass
+    }
+  }
+
+  public void testGetNestedTreesReturnsSingleTree() {
+    rootBuilder.getBuilderForSubMessageField(OPTIONAL_NESTED_MESSAGE);
+    TextFormatParseInfoTree root = rootBuilder.build();
+    assertEquals(1, root.getNestedTrees(OPTIONAL_NESTED_MESSAGE).size());
+    TextFormatParseInfoTree subtree = root.getNestedTrees(OPTIONAL_NESTED_MESSAGE).get(0);
+    assertNotNull(subtree);
+  }
+
+  public void testGetNestedTreesReturnsMultipleTrees() {
+    TextFormatParseInfoTree.Builder subtree1Builder =
+        rootBuilder.getBuilderForSubMessageField(REPEATED_NESTED_MESSAGE);
+    subtree1Builder.getBuilderForSubMessageField(FIELD_BB);
+    subtree1Builder.getBuilderForSubMessageField(FIELD_BB);
+    TextFormatParseInfoTree.Builder subtree2Builder =
+        rootBuilder.getBuilderForSubMessageField(REPEATED_NESTED_MESSAGE);
+    subtree2Builder.getBuilderForSubMessageField(FIELD_BB);
+    TextFormatParseInfoTree root = rootBuilder.build();
+    assertEquals(2, root.getNestedTrees(REPEATED_NESTED_MESSAGE).size());
+    assertEquals(
+        2, root.getNestedTrees(REPEATED_NESTED_MESSAGE).get(0).getNestedTrees(FIELD_BB).size());
+    assertEquals(
+        1, root.getNestedTrees(REPEATED_NESTED_MESSAGE).get(1).getNestedTrees(FIELD_BB).size());
+  }
+}
diff --git a/java/core/src/test/java/com/google/protobuf/TextFormatParseLocationTest.java b/java/core/src/test/java/com/google/protobuf/TextFormatParseLocationTest.java
new file mode 100644
index 00000000..c42bfa6e
--- /dev/null
+++ b/java/core/src/test/java/com/google/protobuf/TextFormatParseLocationTest.java
@@ -0,0 +1,86 @@
+// 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 junit.framework.TestCase;
+
+/**
+ * Test @{link TextFormatParseLocation}.
+ */
+public class TextFormatParseLocationTest extends TestCase {
+
+  public void testCreateEmpty() {
+    TextFormatParseLocation location = TextFormatParseLocation.create(-1, -1);
+    assertEquals(TextFormatParseLocation.EMPTY, location);
+  }
+
+  public void testCreate() {
+    TextFormatParseLocation location = TextFormatParseLocation.create(2, 1);
+    assertEquals(2, location.getLine());
+    assertEquals(1, location.getColumn());
+  }
+
+  public void testCreateThrowsIllegalArgumentExceptionForInvalidIndex() {
+    try {
+      TextFormatParseLocation.create(-1, 0);
+      fail("Should throw IllegalArgumentException if line is less than 0");
+    } catch (IllegalArgumentException unused) {
+      // pass
+    }
+    try {
+      TextFormatParseLocation.create(0, -1);
+      fail("Should throw, column < 0");
+    } catch (IllegalArgumentException unused) {
+      // pass
+    }
+  }
+
+  public void testHashCode() {
+    TextFormatParseLocation loc0 = TextFormatParseLocation.create(2, 1);
+    TextFormatParseLocation loc1 = TextFormatParseLocation.create(2, 1);
+
+    assertEquals(loc0.hashCode(), loc1.hashCode());
+    assertEquals(
+        TextFormatParseLocation.EMPTY.hashCode(), TextFormatParseLocation.EMPTY.hashCode());
+  }
+
+  public void testEquals() {
+    TextFormatParseLocation loc0 = TextFormatParseLocation.create(2, 1);
+    TextFormatParseLocation loc1 = TextFormatParseLocation.create(1, 2);
+    TextFormatParseLocation loc2 = TextFormatParseLocation.create(2, 2);
+    TextFormatParseLocation loc3 = TextFormatParseLocation.create(2, 1);
+
+    assertEquals(loc0, loc3);
+    assertNotSame(loc0, loc1);
+    assertNotSame(loc0, loc2);
+    assertNotSame(loc1, loc2);
+  }
+}
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 1df4fad7..3f47d924 100644
--- a/java/core/src/test/java/com/google/protobuf/TextFormatTest.java
+++ b/java/core/src/test/java/com/google/protobuf/TextFormatTest.java
@@ -30,6 +30,7 @@
 
 package com.google.protobuf;
 
+import com.google.protobuf.Descriptors.Descriptor;
 import com.google.protobuf.Descriptors.FieldDescriptor;
 import com.google.protobuf.TextFormat.Parser.SingularOverwritePolicy;
 import protobuf_unittest.UnittestMset.TestMessageSetExtension1;
@@ -45,6 +46,7 @@ import proto2_wireformat_unittest.UnittestMsetWireFormat.TestMessageSet;
 import junit.framework.TestCase;
 
 import java.io.StringReader;
+import java.util.List;
 
 /**
  * Test case for {@link TextFormat}.
@@ -568,6 +570,16 @@ public class TextFormatTest extends TestCase {
     assertEquals(kEscapeTestString,
       TextFormat.unescapeText(kEscapeTestStringEscaped));
 
+    // Invariant
+    assertEquals("hello",
+        TextFormat.escapeBytes(bytes("hello")));
+    assertEquals("hello",
+        TextFormat.escapeText("hello"));
+    assertEquals(bytes("hello"),
+        TextFormat.unescapeBytes("hello"));
+    assertEquals("hello",
+        TextFormat.unescapeText("hello"));
+
     // Unicode handling.
     assertEquals("\\341\\210\\264", TextFormat.escapeText("\u1234"));
     assertEquals("\\341\\210\\264",
@@ -811,7 +823,6 @@ public class TextFormatTest extends TestCase {
 
   private void assertPrintFieldValue(String expect, Object value,
       String fieldName) throws Exception {
-    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
     StringBuilder sb = new StringBuilder();
     TextFormat.printFieldValue(
         TestAllTypes.getDescriptor().findFieldByName(fieldName),
@@ -1018,4 +1029,98 @@ public class TextFormatTest extends TestCase {
     assertFalse(oneof.hasFooString());
     assertTrue(oneof.hasFooInt());
   }
+
+  // =======================================================================
+  // test location information
+
+  public void testParseInfoTreeBuilding() throws Exception {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+
+    Descriptor descriptor = TestAllTypes.getDescriptor();
+    TextFormatParseInfoTree.Builder treeBuilder = TextFormatParseInfoTree.builder();
+    // Set to allow unknown fields
+    TextFormat.Parser parser =
+        TextFormat.Parser.newBuilder()
+            .setParseInfoTreeBuilder(treeBuilder)
+            .build();
+
+    final String stringData =
+        "optional_int32: 1\n"
+        + "optional_int64: 2\n"
+        + "  optional_double: 2.4\n"
+        + "repeated_int32: 5\n"
+        + "repeated_int32: 10\n"
+        + "optional_nested_message <\n"
+        + "  bb: 78\n"
+        + ">\n"
+        + "repeated_nested_message <\n"
+        + "  bb: 79\n"
+        + ">\n"
+        + "repeated_nested_message <\n"
+        + "  bb: 80\n"
+        + ">";
+
+    parser.merge(stringData, builder);
+    TextFormatParseInfoTree tree = treeBuilder.build();
+
+    // Verify that the tree has the correct positions.
+    assertLocation(tree, descriptor, "optional_int32", 0, 0, 0);
+    assertLocation(tree, descriptor, "optional_int64", 0, 1, 0);
+    assertLocation(tree, descriptor, "optional_double", 0, 2, 2);
+
+    assertLocation(tree, descriptor, "repeated_int32", 0, 3, 0);
+    assertLocation(tree, descriptor, "repeated_int32", 1, 4, 0);
+
+    assertLocation(tree, descriptor, "optional_nested_message", 0, 5, 0);
+    assertLocation(tree, descriptor, "repeated_nested_message", 0, 8, 0);
+    assertLocation(tree, descriptor, "repeated_nested_message", 1, 11, 0);
+
+    // Check for fields not set. For an invalid field, the location returned should be -1, -1.
+    assertLocation(tree, descriptor, "repeated_int64", 0, -1, -1);
+    assertLocation(tree, descriptor, "repeated_int32", 6, -1, -1);
+
+    // Verify inside the nested message.
+    FieldDescriptor nestedField = descriptor.findFieldByName("optional_nested_message");
+
+    TextFormatParseInfoTree nestedTree = tree.getNestedTrees(nestedField).get(0);
+    assertLocation(nestedTree, nestedField.getMessageType(), "bb", 0, 6, 2);
+
+    // Verify inside another nested message.
+    nestedField = descriptor.findFieldByName("repeated_nested_message");
+    nestedTree = tree.getNestedTrees(nestedField).get(0);
+    assertLocation(nestedTree, nestedField.getMessageType(), "bb", 0, 9, 2);
+
+    nestedTree = tree.getNestedTrees(nestedField).get(1);
+    assertLocation(nestedTree, nestedField.getMessageType(), "bb", 0, 12, 2);
+
+    // Verify a NULL tree for an unknown nested field.
+    try {
+      tree.getNestedTree(nestedField, 2);
+      fail("unknown nested field should throw");
+    } catch (IllegalArgumentException unused) {
+      // pass
+    }
+  }
+
+  private void assertLocation(
+      TextFormatParseInfoTree tree,
+      final Descriptor descriptor,
+      final String fieldName,
+      int index,
+      int line,
+      int column) {
+    List<TextFormatParseLocation> locs = tree.getLocations(descriptor.findFieldByName(fieldName));
+    if (index < locs.size()) {
+      TextFormatParseLocation location = locs.get(index);
+      TextFormatParseLocation expected = TextFormatParseLocation.create(line, column);
+      assertEquals(expected, location);
+    } else if (line != -1 && column != -1) {
+      fail(
+          String.format(
+              "Tree/descriptor/fieldname did not contain index %d, line %d column %d expected",
+              index,
+              line,
+              column));
+    }
+  }
 }
diff --git a/java/core/src/test/java/com/google/protobuf/UnknownFieldSetLiteTest.java b/java/core/src/test/java/com/google/protobuf/UnknownFieldSetLiteTest.java
index dc987379..573cd665 100644
--- a/java/core/src/test/java/com/google/protobuf/UnknownFieldSetLiteTest.java
+++ b/java/core/src/test/java/com/google/protobuf/UnknownFieldSetLiteTest.java
@@ -47,46 +47,6 @@ import java.io.IOException;
  * @author dweis@google.com (Daniel Weis)
  */
 public class UnknownFieldSetLiteTest extends TestCase {
-
-  public void testNoDataIsDefaultInstance() {
-    assertSame(
-        UnknownFieldSetLite.getDefaultInstance(),
-        UnknownFieldSetLite.newBuilder()
-            .build());
-  }
-  
-  public void testBuilderReuse() throws IOException {
-    UnknownFieldSetLite.Builder builder = UnknownFieldSetLite.newBuilder();
-    builder.mergeVarintField(10, 2);
-    builder.build();
-
-    try {
-      builder.build();
-      fail();
-    } catch (UnsupportedOperationException e) {
-      // Expected.
-    }
-
-    try {
-      builder.mergeFieldFrom(0, CodedInputStream.newInstance(new byte[0]));
-      fail();
-    } catch (UnsupportedOperationException e) {
-      // Expected.
-    }
-
-    try {
-      builder.mergeVarintField(5, 1);
-      fail();
-    } catch (UnsupportedOperationException e) {
-      // Expected.
-    }
-  }
-
-  public void testBuilderReuse_empty() {
-    UnknownFieldSetLite.Builder builder = UnknownFieldSetLite.newBuilder();
-    builder.build();
-    builder.build();
-  }
   
   public void testDefaultInstance() {
     UnknownFieldSetLite unknownFields = UnknownFieldSetLite.getDefaultInstance();
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 0175005d..b3aabb8f 100644
--- a/java/core/src/test/java/com/google/protobuf/WireFormatTest.java
+++ b/java/core/src/test/java/com/google/protobuf/WireFormatTest.java
@@ -30,12 +30,11 @@
 
 package com.google.protobuf;
 
-import junit.framework.TestCase;
-
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.util.List;
-
+import com.google.protobuf.UnittestLite.TestAllExtensionsLite;
+import com.google.protobuf.UnittestLite.TestPackedExtensionsLite;
+import protobuf_unittest.UnittestMset.RawMessageSet;
+import protobuf_unittest.UnittestMset.TestMessageSetExtension1;
+import protobuf_unittest.UnittestMset.TestMessageSetExtension2;
 import protobuf_unittest.UnittestProto;
 import protobuf_unittest.UnittestProto.TestAllExtensions;
 import protobuf_unittest.UnittestProto.TestAllTypes;
@@ -44,12 +43,13 @@ import protobuf_unittest.UnittestProto.TestOneof2;
 import protobuf_unittest.UnittestProto.TestOneofBackwardsCompatible;
 import protobuf_unittest.UnittestProto.TestPackedExtensions;
 import protobuf_unittest.UnittestProto.TestPackedTypes;
-import protobuf_unittest.UnittestMset.RawMessageSet;
-import protobuf_unittest.UnittestMset.TestMessageSetExtension1;
-import protobuf_unittest.UnittestMset.TestMessageSetExtension2;
 import proto2_wireformat_unittest.UnittestMsetWireFormat.TestMessageSet;
-import com.google.protobuf.UnittestLite.TestAllExtensionsLite;
-import com.google.protobuf.UnittestLite.TestPackedExtensionsLite;
+
+import junit.framework.TestCase;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.util.List;
 
 /**
  * Tests related to parsing and serialization.
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 86837250..f75484de 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
@@ -39,6 +39,13 @@ package protobuf_unittest.lite_equals_and_hash;
 option java_generate_equals_and_hash = true;
 option optimize_for = LITE_RUNTIME;
 
+message TestOneofEquals {
+  oneof oneof_field {
+    string name = 1;
+    int32 value = 2;
+  }
+}
+
 message Foo {
   optional int32 value = 1;
   repeated Bar bar = 2;
@@ -70,3 +77,8 @@ extend Foo {
   }
 }
 
+message TestRecursiveOneof {
+  oneof Foo {
+    TestRecursiveOneof r = 1;
+  }
+}