Down-integrate from internal code base.

33 files changed, 2784 insertions, 52 deletions

diff --git a/java/src/test/java/com/google/protobuf/CodedInputStreamTest.java b/java/src/test/java/com/google/protobuf/CodedInputStreamTest.java
index 3f656e25..18d8142c 100644
--- a/java/src/test/java/com/google/protobuf/CodedInputStreamTest.java
+++ b/java/src/test/java/com/google/protobuf/CodedInputStreamTest.java
@@ -455,19 +455,19 @@ public class CodedInputStreamTest extends TestCase {
   }
 
   public void testMaliciousRecursion() throws Exception {
-    ByteString data64 = makeRecursiveMessage(64).toByteString();
-    ByteString data65 = makeRecursiveMessage(65).toByteString();
+    ByteString data100 = makeRecursiveMessage(100).toByteString();
+    ByteString data101 = makeRecursiveMessage(101).toByteString();
 
-    assertMessageDepth(TestRecursiveMessage.parseFrom(data64), 64);
+    assertMessageDepth(TestRecursiveMessage.parseFrom(data100), 100);
 
     try {
-      TestRecursiveMessage.parseFrom(data65);
+      TestRecursiveMessage.parseFrom(data101);
       fail("Should have thrown an exception!");
     } catch (InvalidProtocolBufferException e) {
       // success.
     }
 
-    CodedInputStream input = data64.newCodedInput();
+    CodedInputStream input = data100.newCodedInput();
     input.setRecursionLimit(8);
     try {
       TestRecursiveMessage.parseFrom(input);
diff --git a/java/src/test/java/com/google/protobuf/DescriptorsTest.java b/java/src/test/java/com/google/protobuf/DescriptorsTest.java
index 0092771b..05832a12 100644
--- a/java/src/test/java/com/google/protobuf/DescriptorsTest.java
+++ b/java/src/test/java/com/google/protobuf/DescriptorsTest.java
@@ -706,6 +706,12 @@ public class DescriptorsTest extends TestCase {
     assertTrue(TestMultipleExtensionRanges.getDescriptor().isExtensionNumber(4143));
   }
 
+  public void testToString() {
+    assertEquals("protobuf_unittest.TestAllTypes.optional_uint64",
+        UnittestProto.TestAllTypes.getDescriptor().findFieldByNumber(
+            UnittestProto.TestAllTypes.OPTIONAL_UINT64_FIELD_NUMBER).toString());
+  }
+
   public void testPackedEnumField() throws Exception {
     FileDescriptorProto fileDescriptorProto = FileDescriptorProto.newBuilder()
         .setName("foo.proto")
diff --git a/java/src/test/java/com/google/protobuf/FieldPresenceTest.java b/java/src/test/java/com/google/protobuf/FieldPresenceTest.java
new file mode 100644
index 00000000..acf2b023
--- /dev/null
+++ b/java/src/test/java/com/google/protobuf/FieldPresenceTest.java
@@ -0,0 +1,363 @@
+// 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 com.google.protobuf.FieldPresenceTestProto.TestAllTypes;
+import com.google.protobuf.FieldPresenceTestProto.TestOptionalFieldsOnly;
+import com.google.protobuf.FieldPresenceTestProto.TestRepeatedFieldsOnly;
+import protobuf_unittest.UnittestProto;
+
+import junit.framework.TestCase;
+
+/**
+ * Unit tests for protos that doesn't support field presence test for optional
+ * non-message fields.
+ */
+public class FieldPresenceTest extends TestCase {
+  private static boolean hasMethod(Class clazz, String name) {
+    try {
+      if (clazz.getMethod(name, new Class[]{}) != null) {
+        return true;
+      } else {
+        return false;
+      }
+    } catch (NoSuchMethodException e) {
+      return false;
+    }
+  }
+
+  private static boolean isHasMethodRemoved(
+      Class classWithFieldPresence,
+      Class classWithoutFieldPresence,
+      String camelName) {
+    return hasMethod(classWithFieldPresence, "get" + camelName)
+        && hasMethod(classWithFieldPresence, "has" + camelName)
+        && hasMethod(classWithoutFieldPresence, "get" + camelName)
+        && !hasMethod(classWithoutFieldPresence, "has" + camelName);
+  }
+
+  public void testHasMethod() {
+    // Optional non-message fields don't have a hasFoo() method generated.
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.class,
+        TestAllTypes.class,
+        "OptionalInt32"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.class,
+        TestAllTypes.class,
+        "OptionalString"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.class,
+        TestAllTypes.class,
+        "OptionalBytes"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.class,
+        TestAllTypes.class,
+        "OptionalNestedEnum"));
+
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.Builder.class,
+        TestAllTypes.Builder.class,
+        "OptionalInt32"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.Builder.class,
+        TestAllTypes.Builder.class,
+        "OptionalString"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.Builder.class,
+        TestAllTypes.Builder.class,
+        "OptionalBytes"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.Builder.class,
+        TestAllTypes.Builder.class,
+        "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(
+        UnittestProto.TestAllTypes.class,
+        TestAllTypes.class,
+        "OneofUint32"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.class,
+        TestAllTypes.class,
+        "OneofString"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.class,
+        TestAllTypes.class,
+        "OneofBytes"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.class,
+        TestAllTypes.class,
+        "OneofNestedMessage"));
+
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.Builder.class,
+        TestAllTypes.Builder.class,
+        "OneofUint32"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.Builder.class,
+        TestAllTypes.Builder.class,
+        "OneofString"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.Builder.class,
+        TestAllTypes.Builder.class,
+        "OneofBytes"));
+    assertTrue(isHasMethodRemoved(
+        UnittestProto.TestAllTypes.Builder.class,
+        TestAllTypes.Builder.class,
+        "OneofNestedMessage"));
+  }
+
+  public void testFieldPresence() {
+    // Optional non-message fields set to their default value are treated the
+    // same way as not set.
+
+    // Serialization will ignore such fields.
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    builder.setOptionalInt32(0);
+    builder.setOptionalString("");
+    builder.setOptionalBytes(ByteString.EMPTY);
+    builder.setOptionalNestedEnum(TestAllTypes.NestedEnum.FOO);
+    TestAllTypes message = builder.build();
+    assertEquals(0, message.getSerializedSize());
+
+    // mergeFrom() will ignore such fields.
+    TestAllTypes.Builder a = TestAllTypes.newBuilder();
+    a.setOptionalInt32(1);
+    a.setOptionalString("x");
+    a.setOptionalBytes(ByteString.copyFromUtf8("y"));
+    a.setOptionalNestedEnum(TestAllTypes.NestedEnum.BAR);
+    TestAllTypes.Builder b = TestAllTypes.newBuilder();
+    b.setOptionalInt32(0);
+    b.setOptionalString("");
+    b.setOptionalBytes(ByteString.EMPTY);
+    b.setOptionalNestedEnum(TestAllTypes.NestedEnum.FOO);
+    a.mergeFrom(b.build());
+    message = a.build();
+    assertEquals(1, message.getOptionalInt32());
+    assertEquals("x", message.getOptionalString());
+    assertEquals(ByteString.copyFromUtf8("y"), message.getOptionalBytes());
+    assertEquals(TestAllTypes.NestedEnum.BAR, message.getOptionalNestedEnum());
+
+    // equals()/hashCode() should produce the same results.
+    TestAllTypes empty = TestAllTypes.newBuilder().build();
+    message = builder.build();
+    assertTrue(empty.equals(message));
+    assertTrue(message.equals(empty));
+    assertEquals(empty.hashCode(), message.hashCode());
+  }
+
+  public void testFieldPresenceByReflection() {
+    Descriptor descriptor = TestAllTypes.getDescriptor();
+    FieldDescriptor optionalInt32Field = descriptor.findFieldByName("optional_int32");
+    FieldDescriptor optionalStringField = descriptor.findFieldByName("optional_string");
+    FieldDescriptor optionalBytesField = descriptor.findFieldByName("optional_bytes");
+    FieldDescriptor optionalNestedEnumField = descriptor.findFieldByName("optional_nested_enum");
+
+    // Field not present.
+    TestAllTypes message = TestAllTypes.newBuilder().build();
+    assertFalse(message.hasField(optionalInt32Field));
+    assertFalse(message.hasField(optionalStringField));
+    assertFalse(message.hasField(optionalBytesField));
+    assertFalse(message.hasField(optionalNestedEnumField));
+    assertEquals(0, message.getAllFields().size());
+
+    // Field set to default value is seen as not present.
+    message = TestAllTypes.newBuilder()
+        .setOptionalInt32(0)
+        .setOptionalString("")
+        .setOptionalBytes(ByteString.EMPTY)
+        .setOptionalNestedEnum(TestAllTypes.NestedEnum.FOO)
+        .build();
+    assertFalse(message.hasField(optionalInt32Field));
+    assertFalse(message.hasField(optionalStringField));
+    assertFalse(message.hasField(optionalBytesField));
+    assertFalse(message.hasField(optionalNestedEnumField));
+    assertEquals(0, message.getAllFields().size());
+
+    // Field set to non-default value is seen as present.
+    message = TestAllTypes.newBuilder()
+        .setOptionalInt32(1)
+        .setOptionalString("x")
+        .setOptionalBytes(ByteString.copyFromUtf8("y"))
+        .setOptionalNestedEnum(TestAllTypes.NestedEnum.BAR)
+        .build();
+    assertTrue(message.hasField(optionalInt32Field));
+    assertTrue(message.hasField(optionalStringField));
+    assertTrue(message.hasField(optionalBytesField));
+    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());
+    assertTrue(builder.hasOptionalNestedMessage());
+    assertTrue(builder.build().hasOptionalNestedMessage());
+  }
+
+  public void testSerializeAndParse() throws Exception {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    builder.setOptionalInt32(1234);
+    builder.setOptionalString("hello");
+    builder.setOptionalNestedMessage(TestAllTypes.NestedMessage.getDefaultInstance());
+    // Set an oneof field to its default value and expect it to be serialized (i.e.,
+    // an oneof field set to the default value should be treated as present).
+    builder.setOneofInt32(0);
+    ByteString data = builder.build().toByteString();
+
+    TestAllTypes message = TestAllTypes.parseFrom(data);
+    assertEquals(1234, message.getOptionalInt32());
+    assertEquals("hello", message.getOptionalString());
+    // Fields not set will have the default value.
+    assertEquals(ByteString.EMPTY, message.getOptionalBytes());
+    assertEquals(TestAllTypes.NestedEnum.FOO, message.getOptionalNestedEnum());
+    // The message field is set despite that it's set with a default instance.
+    assertTrue(message.hasOptionalNestedMessage());
+    assertEquals(0, message.getOptionalNestedMessage().getValue());
+    // The oneof field set to its default value is also present.
+    assertEquals(
+        TestAllTypes.OneofFieldCase.ONEOF_INT32, message.getOneofFieldCase());
+  }
+
+  // Regression test for b/16173397
+  // Make sure we haven't screwed up the code generation for repeated fields.
+  public void testRepeatedFields() throws Exception {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    builder.setOptionalInt32(1234);
+    builder.setOptionalString("hello");
+    builder.setOptionalNestedMessage(TestAllTypes.NestedMessage.getDefaultInstance());
+    builder.addRepeatedInt32(4321);
+    builder.addRepeatedString("world");
+    builder.addRepeatedNestedMessage(TestAllTypes.NestedMessage.getDefaultInstance());
+    ByteString data = builder.build().toByteString();
+
+    TestOptionalFieldsOnly optionalOnlyMessage = TestOptionalFieldsOnly.parseFrom(data);
+    assertEquals(1234, optionalOnlyMessage.getOptionalInt32());
+    assertEquals("hello", optionalOnlyMessage.getOptionalString());
+    assertTrue(optionalOnlyMessage.hasOptionalNestedMessage());
+    assertEquals(0, optionalOnlyMessage.getOptionalNestedMessage().getValue());
+
+    TestRepeatedFieldsOnly repeatedOnlyMessage = TestRepeatedFieldsOnly.parseFrom(data);
+    assertEquals(1, repeatedOnlyMessage.getRepeatedInt32Count());
+    assertEquals(4321, repeatedOnlyMessage.getRepeatedInt32(0));
+    assertEquals(1, repeatedOnlyMessage.getRepeatedStringCount());
+    assertEquals("world", repeatedOnlyMessage.getRepeatedString(0));
+    assertEquals(1, repeatedOnlyMessage.getRepeatedNestedMessageCount());
+    assertEquals(0, repeatedOnlyMessage.getRepeatedNestedMessage(0).getValue());
+  }
+
+  public void testIsInitialized() throws Exception {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+
+    // Test optional proto2 message fields.
+    UnittestProto.TestRequired.Builder proto2Builder =
+        builder.getOptionalProto2MessageBuilder();
+    assertFalse(builder.isInitialized());
+    assertFalse(builder.buildPartial().isInitialized());
+
+    proto2Builder.setA(1).setB(2).setC(3);
+    assertTrue(builder.isInitialized());
+    assertTrue(builder.buildPartial().isInitialized());
+
+    // Test oneof proto2 message fields.
+    proto2Builder = builder.getOneofProto2MessageBuilder();
+    assertFalse(builder.isInitialized());
+    assertFalse(builder.buildPartial().isInitialized());
+
+    proto2Builder.setA(1).setB(2).setC(3);
+    assertTrue(builder.isInitialized());
+    assertTrue(builder.buildPartial().isInitialized());
+
+    // Test repeated proto2 message fields.
+    proto2Builder = builder.addRepeatedProto2MessageBuilder();
+    assertFalse(builder.isInitialized());
+    assertFalse(builder.buildPartial().isInitialized());
+
+    proto2Builder.setA(1).setB(2).setC(3);
+    assertTrue(builder.isInitialized());
+    assertTrue(builder.buildPartial().isInitialized());
+  }
+
+  
+  // Test that unknown fields are dropped.
+  public void testUnknownFields() throws Exception {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    builder.setOptionalInt32(1234);
+    builder.addRepeatedInt32(5678);
+    TestAllTypes message = builder.build();
+    ByteString data = message.toByteString();
+    
+    TestOptionalFieldsOnly optionalOnlyMessage =
+        TestOptionalFieldsOnly.parseFrom(data);
+    // UnknownFieldSet should be empty.
+    assertEquals(
+        0, optionalOnlyMessage.getUnknownFields().toByteString().size());
+    assertEquals(1234, optionalOnlyMessage.getOptionalInt32());
+    message = TestAllTypes.parseFrom(optionalOnlyMessage.toByteString());
+    assertEquals(1234, message.getOptionalInt32());
+    // The repeated field is discarded because it's unknown to the optional-only
+    // message.
+    assertEquals(0, message.getRepeatedInt32Count());
+    
+    DynamicMessage dynamicOptionalOnlyMessage =
+        DynamicMessage.getDefaultInstance(
+            TestOptionalFieldsOnly.getDescriptor())
+        .getParserForType().parseFrom(data);
+    assertEquals(
+        0, dynamicOptionalOnlyMessage.getUnknownFields().toByteString().size());
+    assertEquals(optionalOnlyMessage.toByteString(),
+        dynamicOptionalOnlyMessage.toByteString());
+  }
+}
diff --git a/java/src/test/java/com/google/protobuf/GeneratedMessageTest.java b/java/src/test/java/com/google/protobuf/GeneratedMessageTest.java
index 0b3482c3..41ed7bd0 100644
--- a/java/src/test/java/com/google/protobuf/GeneratedMessageTest.java
+++ b/java/src/test/java/com/google/protobuf/GeneratedMessageTest.java
@@ -157,15 +157,12 @@ public class GeneratedMessageTest extends TestCase {
   public void testProtosShareRepeatedArraysIfDidntChange() throws Exception {
     TestAllTypes.Builder builder = TestAllTypes.newBuilder();
     builder.addRepeatedInt32(100);
-    builder.addRepeatedImportEnum(UnittestImport.ImportEnum.IMPORT_BAR);
     builder.addRepeatedForeignMessage(ForeignMessage.getDefaultInstance());
 
     TestAllTypes value1 = builder.build();
     TestAllTypes value2 = value1.toBuilder().build();
 
     assertSame(value1.getRepeatedInt32List(), value2.getRepeatedInt32List());
-    assertSame(value1.getRepeatedImportEnumList(),
-        value2.getRepeatedImportEnumList());
     assertSame(value1.getRepeatedForeignMessageList(),
         value2.getRepeatedForeignMessageList());
   }
@@ -1512,4 +1509,142 @@ public class GeneratedMessageTest extends TestCase {
       assertEquals(message2.getFooMessage().getQuxInt(), 234);
     }
   }
+
+  public void testGetRepeatedFieldBuilder() {
+    Descriptor descriptor = TestAllTypes.getDescriptor();
+
+    FieldDescriptor fieldDescriptor =
+        descriptor.findFieldByName("repeated_nested_message");
+    FieldDescriptor foreignFieldDescriptor =
+        descriptor.findFieldByName("repeated_foreign_message");
+    FieldDescriptor importFieldDescriptor =
+        descriptor.findFieldByName("repeated_import_message");
+
+    // Mutate the message with new field builder
+    // Mutate nested message
+    TestAllTypes.Builder builder1 = TestAllTypes.newBuilder();
+    Message.Builder fieldBuilder1 = builder1.newBuilderForField(
+        fieldDescriptor);
+    FieldDescriptor subFieldDescriptor1 =
+        fieldBuilder1.getDescriptorForType().findFieldByName("bb");
+    fieldBuilder1.setField(subFieldDescriptor1, 1);
+    builder1.addRepeatedField(fieldDescriptor, fieldBuilder1.build());
+
+    // Mutate foreign message
+    Message.Builder foreignFieldBuilder1 = builder1.newBuilderForField(
+        foreignFieldDescriptor);
+    FieldDescriptor subForeignFieldDescriptor1 =
+        foreignFieldBuilder1.getDescriptorForType().findFieldByName("c");
+    foreignFieldBuilder1.setField(subForeignFieldDescriptor1, 2);
+    builder1.addRepeatedField(foreignFieldDescriptor,
+        foreignFieldBuilder1.build());
+
+    // Mutate import message
+    Message.Builder importFieldBuilder1 = builder1.newBuilderForField(
+        importFieldDescriptor);
+    FieldDescriptor subImportFieldDescriptor1 =
+        importFieldBuilder1.getDescriptorForType().findFieldByName("d");
+    importFieldBuilder1.setField(subImportFieldDescriptor1, 3);
+    builder1.addRepeatedField(importFieldDescriptor,
+        importFieldBuilder1.build());
+
+    Message newMessage1 = builder1.build();
+
+    // Mutate the message with existing field builder
+    // Mutate nested message
+    TestAllTypes.Builder builder2 = TestAllTypes.newBuilder();
+    builder2.addRepeatedNestedMessageBuilder();
+    Message.Builder fieldBuilder2 = builder2.getRepeatedFieldBuilder(
+        fieldDescriptor, 0);
+    FieldDescriptor subFieldDescriptor2 =
+        fieldBuilder2.getDescriptorForType().findFieldByName("bb");
+    fieldBuilder2.setField(subFieldDescriptor2, 1);
+
+    // Mutate foreign message
+    Message.Builder foreignFieldBuilder2 = builder2.newBuilderForField(
+        foreignFieldDescriptor);
+    FieldDescriptor subForeignFieldDescriptor2 =
+        foreignFieldBuilder2.getDescriptorForType().findFieldByName("c");
+    foreignFieldBuilder2.setField(subForeignFieldDescriptor2, 2);
+    builder2.addRepeatedField(foreignFieldDescriptor,
+        foreignFieldBuilder2.build());
+
+    // Mutate import message
+    Message.Builder importFieldBuilder2 = builder2.newBuilderForField(
+        importFieldDescriptor);
+    FieldDescriptor subImportFieldDescriptor2 =
+        importFieldBuilder2.getDescriptorForType().findFieldByName("d");
+    importFieldBuilder2.setField(subImportFieldDescriptor2, 3);
+    builder2.addRepeatedField(importFieldDescriptor,
+        importFieldBuilder2.build());
+
+    Message newMessage2 = builder2.build();
+
+    // These two messages should be equal.
+    assertEquals(newMessage1, newMessage2);
+  }
+
+  public void testGetRepeatedFieldBuilderWithInitializedValue() {
+    Descriptor descriptor = TestAllTypes.getDescriptor();
+    FieldDescriptor fieldDescriptor =
+        descriptor.findFieldByName("repeated_nested_message");
+
+    // Before setting field, builder is initialized by default value. 
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    builder.addRepeatedNestedMessageBuilder();
+    NestedMessage.Builder fieldBuilder =
+        (NestedMessage.Builder) builder.getRepeatedFieldBuilder(fieldDescriptor, 0);
+    assertEquals(0, fieldBuilder.getBb());
+
+    // Setting field value with new field builder instance.
+    builder = TestAllTypes.newBuilder();
+    NestedMessage.Builder newFieldBuilder =
+        builder.addRepeatedNestedMessageBuilder();
+    newFieldBuilder.setBb(2);
+    // Then get the field builder instance by getRepeatedFieldBuilder().
+    fieldBuilder =
+        (NestedMessage.Builder) builder.getRepeatedFieldBuilder(fieldDescriptor, 0);
+    // It should contain new value.
+    assertEquals(2, fieldBuilder.getBb());
+    // These two builder should be equal.
+    assertSame(fieldBuilder, newFieldBuilder);
+  }
+
+  public void testGetRepeatedFieldBuilderNotSupportedException() {
+    Descriptor descriptor = TestAllTypes.getDescriptor();
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    try {
+      builder.getRepeatedFieldBuilder(descriptor.findFieldByName("repeated_int32"), 0);
+      fail("Exception was not thrown");
+    } catch (UnsupportedOperationException e) {
+      // We expect this exception.
+    }
+    try {
+      builder.getRepeatedFieldBuilder(
+          descriptor.findFieldByName("repeated_nested_enum"), 0);
+      fail("Exception was not thrown");
+    } catch (UnsupportedOperationException e) {
+      // We expect this exception.
+    }
+    try {
+      builder.getRepeatedFieldBuilder(descriptor.findFieldByName("optional_int32"), 0);
+      fail("Exception was not thrown");
+    } catch (UnsupportedOperationException e) {
+      // We expect this exception.
+    }
+    try {
+      builder.getRepeatedFieldBuilder(
+          descriptor.findFieldByName("optional_nested_enum"), 0);
+      fail("Exception was not thrown");
+    } catch (UnsupportedOperationException e) {
+      // We expect this exception.
+    }
+    try {
+      builder.getRepeatedFieldBuilder(
+          descriptor.findFieldByName("optional_nested_message"), 0);
+      fail("Exception was not thrown");
+    } catch (UnsupportedOperationException e) {
+      // We expect this exception.
+    }
+  }
 }
diff --git a/java/src/test/java/com/google/protobuf/LazyMessageLiteTest.java b/java/src/test/java/com/google/protobuf/LazyMessageLiteTest.java
index 00e3a843..9de794fe 100644
--- a/java/src/test/java/com/google/protobuf/LazyMessageLiteTest.java
+++ b/java/src/test/java/com/google/protobuf/LazyMessageLiteTest.java
@@ -36,8 +36,6 @@ import protobuf_unittest.LazyFieldsLite.LazyNestedInnerMessageLite;
 
 import junit.framework.TestCase;
 
-import org.easymock.classextension.EasyMock;
-
 import java.util.ArrayList;
 
 /**
@@ -52,14 +50,10 @@ public class LazyMessageLiteTest extends TestCase {
   @Override
   protected void setUp() throws Exception {
     super.setUp();
-
-    originalLazyInnerMessageLiteParser = LazyInnerMessageLite.PARSER;
   }
 
   @Override
   protected void tearDown() throws Exception {
-    LazyInnerMessageLite.PARSER = originalLazyInnerMessageLiteParser;
-
     super.tearDown();
   }
 
@@ -291,29 +285,4 @@ public class LazyMessageLiteTest extends TestCase {
 
     assertEquals(bytes, deserialized.toByteString());
   }
-
-  public void testLaziness() throws InvalidProtocolBufferException {
-    LazyInnerMessageLite inner = LazyInnerMessageLite.newBuilder()
-        .setNum(2)
-        .build();
-    LazyMessageLite outer = LazyMessageLite.newBuilder()
-        .setNum(1)
-        .setInner(inner)
-        .setOneofInner(inner)
-        .build();
-    ByteString bytes = outer.toByteString();
-
-
-    // The parser for inner / oneofInner message shouldn't be used if
-    // getInner / getOneofInner is not called.
-    LazyInnerMessageLite.PARSER = EasyMock.createStrictMock(Parser.class);
-
-    EasyMock.replay(LazyInnerMessageLite.PARSER);
-
-    LazyMessageLite deserialized = LazyMessageLite.parseFrom(bytes);
-    assertEquals(1, deserialized.getNum());
-    assertEquals(421,  deserialized.getNumWithDefault());
-
-    EasyMock.verify(LazyInnerMessageLite.PARSER);
-  }
 }
diff --git a/java/src/test/java/com/google/protobuf/LiteEqualsAndHashTest.java b/java/src/test/java/com/google/protobuf/LiteEqualsAndHashTest.java
index 94f4fcf5..035917c8 100644
--- a/java/src/test/java/com/google/protobuf/LiteEqualsAndHashTest.java
+++ b/java/src/test/java/com/google/protobuf/LiteEqualsAndHashTest.java
@@ -82,4 +82,27 @@ public class LiteEqualsAndHashTest extends TestCase {
     BarPrime barPrime = BarPrime.newBuilder().setName("bar").build();
     assertFalse(bar.equals(barPrime));
   }
+
+  public void testEqualsAndHashCodeWithUnknownFields() throws InvalidProtocolBufferException {
+    Foo fooWithOnlyValue = Foo.newBuilder()
+        .setValue(1)
+        .build();
+
+    Foo fooWithValueAndExtension = fooWithOnlyValue.toBuilder()
+        .setValue(1)
+        .setExtension(Bar.fooExt, Bar.newBuilder()
+            .setName("name")
+            .build())
+        .build();
+
+    Foo fooWithValueAndUnknownFields = Foo.parseFrom(fooWithValueAndExtension.toByteArray());
+
+    assertEqualsAndHashCodeAreFalse(fooWithOnlyValue, fooWithValueAndUnknownFields);
+    assertEqualsAndHashCodeAreFalse(fooWithValueAndExtension, fooWithValueAndUnknownFields);
+  }
+
+  private void assertEqualsAndHashCodeAreFalse(Object o1, Object o2) {
+    assertFalse(o1.equals(o2));
+    assertFalse(o1.hashCode() == o2.hashCode());
+  }
 }
diff --git a/java/src/test/java/com/google/protobuf/MapForProto2LiteTest.java b/java/src/test/java/com/google/protobuf/MapForProto2LiteTest.java
new file mode 100644
index 00000000..22dbeb76
--- /dev/null
+++ b/java/src/test/java/com/google/protobuf/MapForProto2LiteTest.java
@@ -0,0 +1,277 @@
+// 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 map_lite_test.MapForProto2TestProto.TestMap;
+import map_lite_test.MapForProto2TestProto.TestMap.MessageValue;
+import map_lite_test.MapForProto2TestProto.TestUnknownEnumValue;
+
+import junit.framework.TestCase;
+
+/**
+ * Unit tests for map fields.
+ */
+public class MapForProto2LiteTest extends TestCase {
+  private void setMapValues(TestMap.Builder builder) {
+    builder.getMutableInt32ToInt32Field().put(1, 11);
+    builder.getMutableInt32ToInt32Field().put(2, 22);
+    builder.getMutableInt32ToInt32Field().put(3, 33);
+
+    builder.getMutableInt32ToStringField().put(1, "11");
+    builder.getMutableInt32ToStringField().put(2, "22");
+    builder.getMutableInt32ToStringField().put(3, "33");
+    
+    builder.getMutableInt32ToBytesField().put(1, TestUtil.toBytes("11"));
+    builder.getMutableInt32ToBytesField().put(2, TestUtil.toBytes("22"));
+    builder.getMutableInt32ToBytesField().put(3, TestUtil.toBytes("33"));
+    
+    builder.getMutableInt32ToEnumField().put(1, TestMap.EnumValue.FOO);
+    builder.getMutableInt32ToEnumField().put(2, TestMap.EnumValue.BAR);
+    builder.getMutableInt32ToEnumField().put(3, TestMap.EnumValue.BAZ);
+    
+    builder.getMutableInt32ToMessageField().put(
+        1, MessageValue.newBuilder().setValue(11).build());
+    builder.getMutableInt32ToMessageField().put(
+        2, MessageValue.newBuilder().setValue(22).build());
+    builder.getMutableInt32ToMessageField().put(
+        3, MessageValue.newBuilder().setValue(33).build());
+    
+    builder.getMutableStringToInt32Field().put("1", 11);
+    builder.getMutableStringToInt32Field().put("2", 22);
+    builder.getMutableStringToInt32Field().put("3", 33);
+  }
+
+  private void assertMapValuesSet(TestMap message) {
+    assertEquals(3, message.getInt32ToInt32Field().size());
+    assertEquals(11, message.getInt32ToInt32Field().get(1).intValue());
+    assertEquals(22, message.getInt32ToInt32Field().get(2).intValue());
+    assertEquals(33, message.getInt32ToInt32Field().get(3).intValue());
+
+    assertEquals(3, message.getInt32ToStringField().size());
+    assertEquals("11", message.getInt32ToStringField().get(1));
+    assertEquals("22", message.getInt32ToStringField().get(2));
+    assertEquals("33", message.getInt32ToStringField().get(3));
+    
+    assertEquals(3, message.getInt32ToBytesField().size());
+    assertEquals(TestUtil.toBytes("11"), message.getInt32ToBytesField().get(1));
+    assertEquals(TestUtil.toBytes("22"), message.getInt32ToBytesField().get(2));
+    assertEquals(TestUtil.toBytes("33"), message.getInt32ToBytesField().get(3));
+    
+    assertEquals(3, message.getInt32ToEnumField().size());
+    assertEquals(TestMap.EnumValue.FOO, message.getInt32ToEnumField().get(1));
+    assertEquals(TestMap.EnumValue.BAR, message.getInt32ToEnumField().get(2));
+    assertEquals(TestMap.EnumValue.BAZ, message.getInt32ToEnumField().get(3));
+    
+    assertEquals(3, message.getInt32ToMessageField().size());
+    assertEquals(11, message.getInt32ToMessageField().get(1).getValue());
+    assertEquals(22, message.getInt32ToMessageField().get(2).getValue());
+    assertEquals(33, message.getInt32ToMessageField().get(3).getValue());
+    
+    assertEquals(3, message.getStringToInt32Field().size());
+    assertEquals(11, message.getStringToInt32Field().get("1").intValue());
+    assertEquals(22, message.getStringToInt32Field().get("2").intValue());
+    assertEquals(33, message.getStringToInt32Field().get("3").intValue());
+  }
+
+  private void updateMapValues(TestMap.Builder builder) {
+    builder.getMutableInt32ToInt32Field().put(1, 111);
+    builder.getMutableInt32ToInt32Field().remove(2);
+    builder.getMutableInt32ToInt32Field().put(4, 44);
+
+    builder.getMutableInt32ToStringField().put(1, "111");
+    builder.getMutableInt32ToStringField().remove(2);
+    builder.getMutableInt32ToStringField().put(4, "44");
+    
+    builder.getMutableInt32ToBytesField().put(1, TestUtil.toBytes("111"));
+    builder.getMutableInt32ToBytesField().remove(2);
+    builder.getMutableInt32ToBytesField().put(4, TestUtil.toBytes("44"));
+    
+    builder.getMutableInt32ToEnumField().put(1, TestMap.EnumValue.BAR);
+    builder.getMutableInt32ToEnumField().remove(2);
+    builder.getMutableInt32ToEnumField().put(4, TestMap.EnumValue.QUX);
+    
+    builder.getMutableInt32ToMessageField().put(
+        1, MessageValue.newBuilder().setValue(111).build());
+    builder.getMutableInt32ToMessageField().remove(2);
+    builder.getMutableInt32ToMessageField().put(
+        4, MessageValue.newBuilder().setValue(44).build());
+    
+    builder.getMutableStringToInt32Field().put("1", 111);
+    builder.getMutableStringToInt32Field().remove("2");
+    builder.getMutableStringToInt32Field().put("4", 44);
+  }
+
+  private void assertMapValuesUpdated(TestMap message) {
+    assertEquals(3, message.getInt32ToInt32Field().size());
+    assertEquals(111, message.getInt32ToInt32Field().get(1).intValue());
+    assertEquals(33, message.getInt32ToInt32Field().get(3).intValue());
+    assertEquals(44, message.getInt32ToInt32Field().get(4).intValue());
+
+    assertEquals(3, message.getInt32ToStringField().size());
+    assertEquals("111", message.getInt32ToStringField().get(1));
+    assertEquals("33", message.getInt32ToStringField().get(3));
+    assertEquals("44", message.getInt32ToStringField().get(4));
+    
+    assertEquals(3, message.getInt32ToBytesField().size());
+    assertEquals(TestUtil.toBytes("111"), message.getInt32ToBytesField().get(1));
+    assertEquals(TestUtil.toBytes("33"), message.getInt32ToBytesField().get(3));
+    assertEquals(TestUtil.toBytes("44"), message.getInt32ToBytesField().get(4));
+    
+    assertEquals(3, message.getInt32ToEnumField().size());
+    assertEquals(TestMap.EnumValue.BAR, message.getInt32ToEnumField().get(1));
+    assertEquals(TestMap.EnumValue.BAZ, message.getInt32ToEnumField().get(3));
+    assertEquals(TestMap.EnumValue.QUX, message.getInt32ToEnumField().get(4));
+    
+    assertEquals(3, message.getInt32ToMessageField().size());
+    assertEquals(111, message.getInt32ToMessageField().get(1).getValue());
+    assertEquals(33, message.getInt32ToMessageField().get(3).getValue());
+    assertEquals(44, message.getInt32ToMessageField().get(4).getValue());
+    
+    assertEquals(3, message.getStringToInt32Field().size());
+    assertEquals(111, message.getStringToInt32Field().get("1").intValue());
+    assertEquals(33, message.getStringToInt32Field().get("3").intValue());
+    assertEquals(44, message.getStringToInt32Field().get("4").intValue());
+  }
+
+  private void assertMapValuesCleared(TestMap message) {
+    assertEquals(0, message.getInt32ToInt32Field().size());
+    assertEquals(0, message.getInt32ToStringField().size());
+    assertEquals(0, message.getInt32ToBytesField().size());
+    assertEquals(0, message.getInt32ToEnumField().size());
+    assertEquals(0, message.getInt32ToMessageField().size());
+    assertEquals(0, message.getStringToInt32Field().size());
+  }
+
+  public void testGettersAndSetters() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    TestMap message = builder.build();
+    assertMapValuesCleared(message);
+    
+    builder = message.toBuilder();
+    setMapValues(builder);
+    message = builder.build();
+    assertMapValuesSet(message);
+    
+    builder = message.toBuilder();
+    updateMapValues(builder);
+    message = builder.build();
+    assertMapValuesUpdated(message);
+    
+    builder = message.toBuilder();
+    builder.clear();
+    message = builder.build();
+    assertMapValuesCleared(message);
+  }
+
+  public void testSerializeAndParse() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    setMapValues(builder);
+    TestMap message = builder.build();
+    assertEquals(message.getSerializedSize(), message.toByteString().size());
+    message = TestMap.PARSER.parseFrom(message.toByteString());
+    assertMapValuesSet(message);
+    
+    builder = message.toBuilder();
+    updateMapValues(builder);
+    message = builder.build();
+    assertEquals(message.getSerializedSize(), message.toByteString().size());
+    message = TestMap.PARSER.parseFrom(message.toByteString());
+    assertMapValuesUpdated(message);
+    
+    builder = message.toBuilder();
+    builder.clear();
+    message = builder.build();
+    assertEquals(message.getSerializedSize(), message.toByteString().size());
+    message = TestMap.PARSER.parseFrom(message.toByteString());
+    assertMapValuesCleared(message);
+  }
+  
+  public void testMergeFrom() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    setMapValues(builder);
+    TestMap message = builder.build();
+    
+    TestMap.Builder other = TestMap.newBuilder();
+    other.mergeFrom(message);
+    assertMapValuesSet(other.build());
+  }
+
+  public void testEqualsAndHashCode() throws Exception {
+    // Test that generated equals() and hashCode() will disregard the order
+    // of map entries when comparing/hashing map fields.
+    
+    // We can't control the order of elements in a HashMap. The best we can do
+    // here is to add elements in different order.
+    TestMap.Builder b1 = TestMap.newBuilder();
+    b1.getMutableInt32ToInt32Field().put(1, 2);
+    b1.getMutableInt32ToInt32Field().put(3, 4);
+    b1.getMutableInt32ToInt32Field().put(5, 6);
+    TestMap m1 = b1.build();
+    
+    TestMap.Builder b2 = TestMap.newBuilder();
+    b2.getMutableInt32ToInt32Field().put(5, 6);
+    b2.getMutableInt32ToInt32Field().put(1, 2);
+    b2.getMutableInt32ToInt32Field().put(3, 4);
+    TestMap m2 = b2.build();
+    
+    assertEquals(m1, m2);
+    assertEquals(m1.hashCode(), m2.hashCode());
+    
+    // Make sure we did compare map fields.
+    b2.getMutableInt32ToInt32Field().put(1, 0);
+    m2 = b2.build();
+    assertFalse(m1.equals(m2));
+    // Don't check m1.hashCode() != m2.hashCode() because it's not guaranteed
+    // to be different.
+  }
+
+  public void testUnknownEnumValues() throws Exception {
+    TestUnknownEnumValue.Builder builder =
+        TestUnknownEnumValue.newBuilder();
+    builder.getMutableInt32ToInt32Field().put(1, 1);
+    builder.getMutableInt32ToInt32Field().put(2, 54321);
+    ByteString data = builder.build().toByteString();
+
+    TestMap message = TestMap.parseFrom(data);
+    // Entries with unknown enum values will be stored into UnknownFieldSet so
+    // there is only one entry in the map.
+    assertEquals(1, message.getInt32ToEnumField().size());
+    assertEquals(TestMap.EnumValue.BAR, message.getInt32ToEnumField().get(1));
+    // Serializing and parsing should preserve the unknown entry.
+    data = message.toByteString();
+    TestUnknownEnumValue messageWithUnknownEnums =
+        TestUnknownEnumValue.parseFrom(data);
+    assertEquals(2, messageWithUnknownEnums.getInt32ToInt32Field().size());
+    assertEquals(1, messageWithUnknownEnums.getInt32ToInt32Field().get(1).intValue());
+    assertEquals(54321, messageWithUnknownEnums.getInt32ToInt32Field().get(2).intValue());
+  }
+  
+}
diff --git a/java/src/test/java/com/google/protobuf/MapForProto2Test.java b/java/src/test/java/com/google/protobuf/MapForProto2Test.java
new file mode 100644
index 00000000..d78c0d94
--- /dev/null
+++ b/java/src/test/java/com/google/protobuf/MapForProto2Test.java
@@ -0,0 +1,488 @@
+// 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 map_test.MapForProto2TestProto.TestMap;
+import map_test.MapForProto2TestProto.TestMap.MessageValue;
+import map_test.MapForProto2TestProto.TestUnknownEnumValue;
+
+import junit.framework.TestCase;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Unit tests for map fields in proto2 protos.
+ */
+public class MapForProto2Test extends TestCase {
+  private void setMapValues(TestMap.Builder builder) {
+    builder.getMutableInt32ToInt32Field().put(1, 11);
+    builder.getMutableInt32ToInt32Field().put(2, 22);
+    builder.getMutableInt32ToInt32Field().put(3, 33);
+
+    builder.getMutableInt32ToStringField().put(1, "11");
+    builder.getMutableInt32ToStringField().put(2, "22");
+    builder.getMutableInt32ToStringField().put(3, "33");
+    
+    builder.getMutableInt32ToBytesField().put(1, TestUtil.toBytes("11"));
+    builder.getMutableInt32ToBytesField().put(2, TestUtil.toBytes("22"));
+    builder.getMutableInt32ToBytesField().put(3, TestUtil.toBytes("33"));
+    
+    builder.getMutableInt32ToEnumField().put(1, TestMap.EnumValue.FOO);
+    builder.getMutableInt32ToEnumField().put(2, TestMap.EnumValue.BAR);
+    builder.getMutableInt32ToEnumField().put(3, TestMap.EnumValue.BAZ);
+    
+    builder.getMutableInt32ToMessageField().put(
+        1, MessageValue.newBuilder().setValue(11).build());
+    builder.getMutableInt32ToMessageField().put(
+        2, MessageValue.newBuilder().setValue(22).build());
+    builder.getMutableInt32ToMessageField().put(
+        3, MessageValue.newBuilder().setValue(33).build());
+    
+    builder.getMutableStringToInt32Field().put("1", 11);
+    builder.getMutableStringToInt32Field().put("2", 22);
+    builder.getMutableStringToInt32Field().put("3", 33);
+  }
+
+  private void assertMapValuesSet(TestMap message) {
+    assertEquals(3, message.getInt32ToInt32Field().size());
+    assertEquals(11, message.getInt32ToInt32Field().get(1).intValue());
+    assertEquals(22, message.getInt32ToInt32Field().get(2).intValue());
+    assertEquals(33, message.getInt32ToInt32Field().get(3).intValue());
+
+    assertEquals(3, message.getInt32ToStringField().size());
+    assertEquals("11", message.getInt32ToStringField().get(1));
+    assertEquals("22", message.getInt32ToStringField().get(2));
+    assertEquals("33", message.getInt32ToStringField().get(3));
+    
+    assertEquals(3, message.getInt32ToBytesField().size());
+    assertEquals(TestUtil.toBytes("11"), message.getInt32ToBytesField().get(1));
+    assertEquals(TestUtil.toBytes("22"), message.getInt32ToBytesField().get(2));
+    assertEquals(TestUtil.toBytes("33"), message.getInt32ToBytesField().get(3));
+    
+    assertEquals(3, message.getInt32ToEnumField().size());
+    assertEquals(TestMap.EnumValue.FOO, message.getInt32ToEnumField().get(1));
+    assertEquals(TestMap.EnumValue.BAR, message.getInt32ToEnumField().get(2));
+    assertEquals(TestMap.EnumValue.BAZ, message.getInt32ToEnumField().get(3));
+    
+    assertEquals(3, message.getInt32ToMessageField().size());
+    assertEquals(11, message.getInt32ToMessageField().get(1).getValue());
+    assertEquals(22, message.getInt32ToMessageField().get(2).getValue());
+    assertEquals(33, message.getInt32ToMessageField().get(3).getValue());
+    
+    assertEquals(3, message.getStringToInt32Field().size());
+    assertEquals(11, message.getStringToInt32Field().get("1").intValue());
+    assertEquals(22, message.getStringToInt32Field().get("2").intValue());
+    assertEquals(33, message.getStringToInt32Field().get("3").intValue());
+  }
+
+  private void updateMapValues(TestMap.Builder builder) {
+    builder.getMutableInt32ToInt32Field().put(1, 111);
+    builder.getMutableInt32ToInt32Field().remove(2);
+    builder.getMutableInt32ToInt32Field().put(4, 44);
+
+    builder.getMutableInt32ToStringField().put(1, "111");
+    builder.getMutableInt32ToStringField().remove(2);
+    builder.getMutableInt32ToStringField().put(4, "44");
+    
+    builder.getMutableInt32ToBytesField().put(1, TestUtil.toBytes("111"));
+    builder.getMutableInt32ToBytesField().remove(2);
+    builder.getMutableInt32ToBytesField().put(4, TestUtil.toBytes("44"));
+    
+    builder.getMutableInt32ToEnumField().put(1, TestMap.EnumValue.BAR);
+    builder.getMutableInt32ToEnumField().remove(2);
+    builder.getMutableInt32ToEnumField().put(4, TestMap.EnumValue.QUX);
+    
+    builder.getMutableInt32ToMessageField().put(
+        1, MessageValue.newBuilder().setValue(111).build());
+    builder.getMutableInt32ToMessageField().remove(2);
+    builder.getMutableInt32ToMessageField().put(
+        4, MessageValue.newBuilder().setValue(44).build());
+    
+    builder.getMutableStringToInt32Field().put("1", 111);
+    builder.getMutableStringToInt32Field().remove("2");
+    builder.getMutableStringToInt32Field().put("4", 44);
+  }
+
+  private void assertMapValuesUpdated(TestMap message) {
+    assertEquals(3, message.getInt32ToInt32Field().size());
+    assertEquals(111, message.getInt32ToInt32Field().get(1).intValue());
+    assertEquals(33, message.getInt32ToInt32Field().get(3).intValue());
+    assertEquals(44, message.getInt32ToInt32Field().get(4).intValue());
+
+    assertEquals(3, message.getInt32ToStringField().size());
+    assertEquals("111", message.getInt32ToStringField().get(1));
+    assertEquals("33", message.getInt32ToStringField().get(3));
+    assertEquals("44", message.getInt32ToStringField().get(4));
+    
+    assertEquals(3, message.getInt32ToBytesField().size());
+    assertEquals(TestUtil.toBytes("111"), message.getInt32ToBytesField().get(1));
+    assertEquals(TestUtil.toBytes("33"), message.getInt32ToBytesField().get(3));
+    assertEquals(TestUtil.toBytes("44"), message.getInt32ToBytesField().get(4));
+    
+    assertEquals(3, message.getInt32ToEnumField().size());
+    assertEquals(TestMap.EnumValue.BAR, message.getInt32ToEnumField().get(1));
+    assertEquals(TestMap.EnumValue.BAZ, message.getInt32ToEnumField().get(3));
+    assertEquals(TestMap.EnumValue.QUX, message.getInt32ToEnumField().get(4));
+    
+    assertEquals(3, message.getInt32ToMessageField().size());
+    assertEquals(111, message.getInt32ToMessageField().get(1).getValue());
+    assertEquals(33, message.getInt32ToMessageField().get(3).getValue());
+    assertEquals(44, message.getInt32ToMessageField().get(4).getValue());
+    
+    assertEquals(3, message.getStringToInt32Field().size());
+    assertEquals(111, message.getStringToInt32Field().get("1").intValue());
+    assertEquals(33, message.getStringToInt32Field().get("3").intValue());
+    assertEquals(44, message.getStringToInt32Field().get("4").intValue());
+  }
+
+  private void assertMapValuesCleared(TestMap message) {
+    assertEquals(0, message.getInt32ToInt32Field().size());
+    assertEquals(0, message.getInt32ToStringField().size());
+    assertEquals(0, message.getInt32ToBytesField().size());
+    assertEquals(0, message.getInt32ToEnumField().size());
+    assertEquals(0, message.getInt32ToMessageField().size());
+    assertEquals(0, message.getStringToInt32Field().size());
+  }
+
+  public void testGettersAndSetters() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    TestMap message = builder.build();
+    assertMapValuesCleared(message);
+    
+    builder = message.toBuilder();
+    setMapValues(builder);
+    message = builder.build();
+    assertMapValuesSet(message);
+    
+    builder = message.toBuilder();
+    updateMapValues(builder);
+    message = builder.build();
+    assertMapValuesUpdated(message);
+    
+    builder = message.toBuilder();
+    builder.clear();
+    message = builder.build();
+    assertMapValuesCleared(message);
+  }
+
+  public void testSerializeAndParse() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    setMapValues(builder);
+    TestMap message = builder.build();
+    assertEquals(message.getSerializedSize(), message.toByteString().size());
+    message = TestMap.PARSER.parseFrom(message.toByteString());
+    assertMapValuesSet(message);
+    
+    builder = message.toBuilder();
+    updateMapValues(builder);
+    message = builder.build();
+    assertEquals(message.getSerializedSize(), message.toByteString().size());
+    message = TestMap.PARSER.parseFrom(message.toByteString());
+    assertMapValuesUpdated(message);
+    
+    builder = message.toBuilder();
+    builder.clear();
+    message = builder.build();
+    assertEquals(message.getSerializedSize(), message.toByteString().size());
+    message = TestMap.PARSER.parseFrom(message.toByteString());
+    assertMapValuesCleared(message);
+  }
+  
+  public void testMergeFrom() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    setMapValues(builder);
+    TestMap message = builder.build();
+    
+    TestMap.Builder other = TestMap.newBuilder();
+    other.mergeFrom(message);
+    assertMapValuesSet(other.build());
+  }
+
+  public void testEqualsAndHashCode() throws Exception {
+    // Test that generated equals() and hashCode() will disregard the order
+    // of map entries when comparing/hashing map fields.
+    
+    // We can't control the order of elements in a HashMap. The best we can do
+    // here is to add elements in different order.
+    TestMap.Builder b1 = TestMap.newBuilder();
+    b1.getMutableInt32ToInt32Field().put(1, 2);
+    b1.getMutableInt32ToInt32Field().put(3, 4);
+    b1.getMutableInt32ToInt32Field().put(5, 6);
+    TestMap m1 = b1.build();
+    
+    TestMap.Builder b2 = TestMap.newBuilder();
+    b2.getMutableInt32ToInt32Field().put(5, 6);
+    b2.getMutableInt32ToInt32Field().put(1, 2);
+    b2.getMutableInt32ToInt32Field().put(3, 4);
+    TestMap m2 = b2.build();
+    
+    assertEquals(m1, m2);
+    assertEquals(m1.hashCode(), m2.hashCode());
+    
+    // Make sure we did compare map fields.
+    b2.getMutableInt32ToInt32Field().put(1, 0);
+    m2 = b2.build();
+    assertFalse(m1.equals(m2));
+    // Don't check m1.hashCode() != m2.hashCode() because it's not guaranteed
+    // to be different.
+  }
+  
+  
+  // The following methods are used to test reflection API.
+  
+  private static FieldDescriptor f(String name) {
+    return TestMap.getDescriptor().findFieldByName(name);
+  }
+  
+  private static Object getFieldValue(Message mapEntry, String name) {
+    FieldDescriptor field = mapEntry.getDescriptorForType().findFieldByName(name);
+    return mapEntry.getField(field);
+  }
+  
+  private static Message.Builder setFieldValue(
+      Message.Builder mapEntry, String name, Object value) {
+    FieldDescriptor field = mapEntry.getDescriptorForType().findFieldByName(name);
+    mapEntry.setField(field, value);
+    return mapEntry;
+  }
+  
+  private static void assertHasMapValues(Message message, String name, Map<?, ?> values) {
+    FieldDescriptor field = f(name);
+    for (Object entry : (List<?>) message.getField(field)) {
+      Message mapEntry = (Message) entry;
+      Object key = getFieldValue(mapEntry, "key");
+      Object value = getFieldValue(mapEntry, "value");
+      assertTrue(values.containsKey(key));
+      assertEquals(value, values.get(key));
+    }
+    assertEquals(values.size(), message.getRepeatedFieldCount(field));
+    for (int i = 0; i < message.getRepeatedFieldCount(field); i++) {
+      Message mapEntry = (Message) message.getRepeatedField(field, i);
+      Object key = getFieldValue(mapEntry, "key");
+      Object value = getFieldValue(mapEntry, "value");
+      assertTrue(values.containsKey(key));
+      assertEquals(value, values.get(key));
+    }
+  }
+  
+  private static <KeyType, ValueType>
+  Message newMapEntry(Message.Builder builder, String name, KeyType key, ValueType value) {
+    FieldDescriptor field = builder.getDescriptorForType().findFieldByName(name);
+    Message.Builder entryBuilder = builder.newBuilderForField(field);
+    FieldDescriptor keyField = entryBuilder.getDescriptorForType().findFieldByName("key");
+    FieldDescriptor valueField = entryBuilder.getDescriptorForType().findFieldByName("value");
+    entryBuilder.setField(keyField, key);
+    entryBuilder.setField(valueField, value);
+    return entryBuilder.build();
+  }
+  
+  private static void setMapValues(Message.Builder builder, String name, Map<?, ?> values) {
+    List<Message> entryList = new ArrayList<Message>();
+    for (Map.Entry<?, ?> entry : values.entrySet()) {
+      entryList.add(newMapEntry(builder, name, entry.getKey(), entry.getValue()));
+    }
+    FieldDescriptor field = builder.getDescriptorForType().findFieldByName(name);
+    builder.setField(field, entryList);
+  }
+  
+  private static <KeyType, ValueType>
+  Map<KeyType, ValueType> mapForValues(
+      KeyType key1, ValueType value1, KeyType key2, ValueType value2) {
+    Map<KeyType, ValueType> map = new HashMap<KeyType, ValueType>();
+    map.put(key1, value1);
+    map.put(key2, value2);
+    return map;
+  }
+
+  public void testReflectionApi() throws Exception {
+    // In reflection API, map fields are just repeated message fields.
+    TestMap.Builder builder = TestMap.newBuilder();
+    builder.getMutableInt32ToInt32Field().put(1, 2);
+    builder.getMutableInt32ToInt32Field().put(3, 4);
+    builder.getMutableInt32ToMessageField().put(
+        11, MessageValue.newBuilder().setValue(22).build());
+    builder.getMutableInt32ToMessageField().put(
+        33, MessageValue.newBuilder().setValue(44).build());
+    TestMap message = builder.build();
+
+    // Test getField(), getRepeatedFieldCount(), getRepeatedField().
+    assertHasMapValues(message, "int32_to_int32_field",
+        mapForValues(1, 2, 3, 4));
+    assertHasMapValues(message, "int32_to_message_field",
+        mapForValues(
+            11, MessageValue.newBuilder().setValue(22).build(),
+            33, MessageValue.newBuilder().setValue(44).build()));
+    
+    // Test clearField()
+    builder.clearField(f("int32_to_int32_field"));
+    builder.clearField(f("int32_to_message_field"));
+    message = builder.build();
+    assertEquals(0, message.getInt32ToInt32Field().size());
+    assertEquals(0, message.getInt32ToMessageField().size());
+    
+    // Test setField()
+    setMapValues(builder, "int32_to_int32_field",
+        mapForValues(11, 22, 33, 44));
+    setMapValues(builder, "int32_to_message_field",
+        mapForValues(
+            111, MessageValue.newBuilder().setValue(222).build(),
+            333, MessageValue.newBuilder().setValue(444).build()));
+    message = builder.build();
+    assertEquals(22, message.getInt32ToInt32Field().get(11).intValue());
+    assertEquals(44, message.getInt32ToInt32Field().get(33).intValue());
+    assertEquals(222, message.getInt32ToMessageField().get(111).getValue());
+    assertEquals(444, message.getInt32ToMessageField().get(333).getValue());
+    
+    // Test addRepeatedField
+    builder.addRepeatedField(f("int32_to_int32_field"),
+        newMapEntry(builder, "int32_to_int32_field", 55, 66));
+    builder.addRepeatedField(f("int32_to_message_field"),
+        newMapEntry(builder, "int32_to_message_field", 555,
+            MessageValue.newBuilder().setValue(666).build()));
+    message = builder.build();
+    assertEquals(66, message.getInt32ToInt32Field().get(55).intValue());
+    assertEquals(666, message.getInt32ToMessageField().get(555).getValue());
+
+    // Test addRepeatedField (overriding existing values)
+    builder.addRepeatedField(f("int32_to_int32_field"),
+        newMapEntry(builder, "int32_to_int32_field", 55, 55));
+    builder.addRepeatedField(f("int32_to_message_field"),
+        newMapEntry(builder, "int32_to_message_field", 555,
+            MessageValue.newBuilder().setValue(555).build()));
+    message = builder.build();
+    assertEquals(55, message.getInt32ToInt32Field().get(55).intValue());
+    assertEquals(555, message.getInt32ToMessageField().get(555).getValue());
+    
+    // Test setRepeatedField
+    for (int i = 0; i < builder.getRepeatedFieldCount(f("int32_to_int32_field")); i++) {
+      Message mapEntry = (Message) builder.getRepeatedField(f("int32_to_int32_field"), i);
+      int oldKey = ((Integer) getFieldValue(mapEntry, "key")).intValue();
+      int oldValue = ((Integer) getFieldValue(mapEntry, "value")).intValue();
+      // Swap key with value for each entry.
+      Message.Builder mapEntryBuilder = mapEntry.toBuilder();
+      setFieldValue(mapEntryBuilder, "key", oldValue);
+      setFieldValue(mapEntryBuilder, "value", oldKey);
+      builder.setRepeatedField(f("int32_to_int32_field"), i, mapEntryBuilder.build());
+    }
+    message = builder.build();
+    assertEquals(11, message.getInt32ToInt32Field().get(22).intValue());
+    assertEquals(33, message.getInt32ToInt32Field().get(44).intValue());
+    assertEquals(55, message.getInt32ToInt32Field().get(55).intValue());
+  }
+  
+  public void testTextFormat() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    setMapValues(builder);
+    TestMap message = builder.build();
+    
+    String textData = TextFormat.printToString(message);
+    
+    builder = TestMap.newBuilder();
+    TextFormat.merge(textData, builder);
+    message = builder.build();
+    
+    assertMapValuesSet(message);
+  }
+  
+  public void testDynamicMessage() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    setMapValues(builder);
+    TestMap message = builder.build();
+    
+    Message dynamicDefaultInstance =
+        DynamicMessage.getDefaultInstance(TestMap.getDescriptor());
+    Message dynamicMessage = dynamicDefaultInstance
+        .newBuilderForType().mergeFrom(message.toByteString()).build();
+    
+    assertEquals(message, dynamicMessage);
+    assertEquals(message.hashCode(), dynamicMessage.hashCode());
+  }
+  
+  public void testReflectionEqualsAndHashCode() throws Exception {
+    // Test that generated equals() and hashCode() will disregard the order
+    // of map entries when comparing/hashing map fields.
+
+    // We use DynamicMessage to test reflection based equals()/hashCode().
+    Message dynamicDefaultInstance =
+        DynamicMessage.getDefaultInstance(TestMap.getDescriptor());
+    FieldDescriptor field = f("int32_to_int32_field");
+    
+    Message.Builder b1 = dynamicDefaultInstance.newBuilderForType();
+    b1.addRepeatedField(field, newMapEntry(b1, "int32_to_int32_field", 1, 2));
+    b1.addRepeatedField(field, newMapEntry(b1, "int32_to_int32_field", 3, 4));
+    b1.addRepeatedField(field, newMapEntry(b1, "int32_to_int32_field", 5, 6));
+    Message m1 = b1.build();
+    
+    Message.Builder b2 = dynamicDefaultInstance.newBuilderForType();
+    b2.addRepeatedField(field, newMapEntry(b2, "int32_to_int32_field", 5, 6));
+    b2.addRepeatedField(field, newMapEntry(b2, "int32_to_int32_field", 1, 2));
+    b2.addRepeatedField(field, newMapEntry(b2, "int32_to_int32_field", 3, 4));
+    Message m2 = b2.build();
+    
+    assertEquals(m1, m2);
+    assertEquals(m1.hashCode(), m2.hashCode());
+    
+    // Make sure we did compare map fields.
+    b2.setRepeatedField(field, 0, newMapEntry(b1, "int32_to_int32_field", 0, 0));
+    m2 = b2.build();
+    assertFalse(m1.equals(m2));
+    // Don't check m1.hashCode() != m2.hashCode() because it's not guaranteed
+    // to be different.
+  }
+  
+  public void testUnknownEnumValues() throws Exception {
+    TestUnknownEnumValue.Builder builder =
+        TestUnknownEnumValue.newBuilder();
+    builder.getMutableInt32ToInt32Field().put(1, 1);
+    builder.getMutableInt32ToInt32Field().put(2, 54321);
+    ByteString data = builder.build().toByteString();
+
+    TestMap message = TestMap.parseFrom(data);
+    // Entries with unknown enum values will be stored into UnknownFieldSet so
+    // there is only one entry in the map.
+    assertEquals(1, message.getInt32ToEnumField().size());
+    assertEquals(TestMap.EnumValue.BAR, message.getInt32ToEnumField().get(1));
+    // UnknownFieldSet should not be empty.
+    assertFalse(message.getUnknownFields().asMap().isEmpty());
+    // Serializing and parsing should preserve the unknown entry.
+    data = message.toByteString();
+    TestUnknownEnumValue messageWithUnknownEnums =
+        TestUnknownEnumValue.parseFrom(data);
+    assertEquals(2, messageWithUnknownEnums.getInt32ToInt32Field().size());
+    assertEquals(1, messageWithUnknownEnums.getInt32ToInt32Field().get(1).intValue());
+    assertEquals(54321, messageWithUnknownEnums.getInt32ToInt32Field().get(2).intValue());
+  }
+
+}
diff --git a/java/src/test/java/com/google/protobuf/MapTest.java b/java/src/test/java/com/google/protobuf/MapTest.java
new file mode 100644
index 00000000..542a20e7
--- /dev/null
+++ b/java/src/test/java/com/google/protobuf/MapTest.java
@@ -0,0 +1,569 @@
+// 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.EnumDescriptor;
+import com.google.protobuf.Descriptors.EnumValueDescriptor;
+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;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Unit tests for map fields.
+ */
+public class MapTest extends TestCase {
+  private void setMapValues(TestMap.Builder builder) {
+    builder.getMutableInt32ToInt32Field().put(1, 11);
+    builder.getMutableInt32ToInt32Field().put(2, 22);
+    builder.getMutableInt32ToInt32Field().put(3, 33);
+
+    builder.getMutableInt32ToStringField().put(1, "11");
+    builder.getMutableInt32ToStringField().put(2, "22");
+    builder.getMutableInt32ToStringField().put(3, "33");
+    
+    builder.getMutableInt32ToBytesField().put(1, TestUtil.toBytes("11"));
+    builder.getMutableInt32ToBytesField().put(2, TestUtil.toBytes("22"));
+    builder.getMutableInt32ToBytesField().put(3, TestUtil.toBytes("33"));
+    
+    builder.getMutableInt32ToEnumField().put(1, TestMap.EnumValue.FOO);
+    builder.getMutableInt32ToEnumField().put(2, TestMap.EnumValue.BAR);
+    builder.getMutableInt32ToEnumField().put(3, TestMap.EnumValue.BAZ);
+    
+    builder.getMutableInt32ToMessageField().put(
+        1, MessageValue.newBuilder().setValue(11).build());
+    builder.getMutableInt32ToMessageField().put(
+        2, MessageValue.newBuilder().setValue(22).build());
+    builder.getMutableInt32ToMessageField().put(
+        3, MessageValue.newBuilder().setValue(33).build());
+    
+    builder.getMutableStringToInt32Field().put("1", 11);
+    builder.getMutableStringToInt32Field().put("2", 22);
+    builder.getMutableStringToInt32Field().put("3", 33);
+  }
+
+  private void assertMapValuesSet(TestMap message) {
+    assertEquals(3, message.getInt32ToInt32Field().size());
+    assertEquals(11, message.getInt32ToInt32Field().get(1).intValue());
+    assertEquals(22, message.getInt32ToInt32Field().get(2).intValue());
+    assertEquals(33, message.getInt32ToInt32Field().get(3).intValue());
+
+    assertEquals(3, message.getInt32ToStringField().size());
+    assertEquals("11", message.getInt32ToStringField().get(1));
+    assertEquals("22", message.getInt32ToStringField().get(2));
+    assertEquals("33", message.getInt32ToStringField().get(3));
+    
+    assertEquals(3, message.getInt32ToBytesField().size());
+    assertEquals(TestUtil.toBytes("11"), message.getInt32ToBytesField().get(1));
+    assertEquals(TestUtil.toBytes("22"), message.getInt32ToBytesField().get(2));
+    assertEquals(TestUtil.toBytes("33"), message.getInt32ToBytesField().get(3));
+    
+    assertEquals(3, message.getInt32ToEnumField().size());
+    assertEquals(TestMap.EnumValue.FOO, message.getInt32ToEnumField().get(1));
+    assertEquals(TestMap.EnumValue.BAR, message.getInt32ToEnumField().get(2));
+    assertEquals(TestMap.EnumValue.BAZ, message.getInt32ToEnumField().get(3));
+    
+    assertEquals(3, message.getInt32ToMessageField().size());
+    assertEquals(11, message.getInt32ToMessageField().get(1).getValue());
+    assertEquals(22, message.getInt32ToMessageField().get(2).getValue());
+    assertEquals(33, message.getInt32ToMessageField().get(3).getValue());
+    
+    assertEquals(3, message.getStringToInt32Field().size());
+    assertEquals(11, message.getStringToInt32Field().get("1").intValue());
+    assertEquals(22, message.getStringToInt32Field().get("2").intValue());
+    assertEquals(33, message.getStringToInt32Field().get("3").intValue());
+  }
+
+  private void updateMapValues(TestMap.Builder builder) {
+    builder.getMutableInt32ToInt32Field().put(1, 111);
+    builder.getMutableInt32ToInt32Field().remove(2);
+    builder.getMutableInt32ToInt32Field().put(4, 44);
+
+    builder.getMutableInt32ToStringField().put(1, "111");
+    builder.getMutableInt32ToStringField().remove(2);
+    builder.getMutableInt32ToStringField().put(4, "44");
+    
+    builder.getMutableInt32ToBytesField().put(1, TestUtil.toBytes("111"));
+    builder.getMutableInt32ToBytesField().remove(2);
+    builder.getMutableInt32ToBytesField().put(4, TestUtil.toBytes("44"));
+    
+    builder.getMutableInt32ToEnumField().put(1, TestMap.EnumValue.BAR);
+    builder.getMutableInt32ToEnumField().remove(2);
+    builder.getMutableInt32ToEnumField().put(4, TestMap.EnumValue.QUX);
+    
+    builder.getMutableInt32ToMessageField().put(
+        1, MessageValue.newBuilder().setValue(111).build());
+    builder.getMutableInt32ToMessageField().remove(2);
+    builder.getMutableInt32ToMessageField().put(
+        4, MessageValue.newBuilder().setValue(44).build());
+    
+    builder.getMutableStringToInt32Field().put("1", 111);
+    builder.getMutableStringToInt32Field().remove("2");
+    builder.getMutableStringToInt32Field().put("4", 44);
+  }
+
+  private void assertMapValuesUpdated(TestMap message) {
+    assertEquals(3, message.getInt32ToInt32Field().size());
+    assertEquals(111, message.getInt32ToInt32Field().get(1).intValue());
+    assertEquals(33, message.getInt32ToInt32Field().get(3).intValue());
+    assertEquals(44, message.getInt32ToInt32Field().get(4).intValue());
+
+    assertEquals(3, message.getInt32ToStringField().size());
+    assertEquals("111", message.getInt32ToStringField().get(1));
+    assertEquals("33", message.getInt32ToStringField().get(3));
+    assertEquals("44", message.getInt32ToStringField().get(4));
+    
+    assertEquals(3, message.getInt32ToBytesField().size());
+    assertEquals(TestUtil.toBytes("111"), message.getInt32ToBytesField().get(1));
+    assertEquals(TestUtil.toBytes("33"), message.getInt32ToBytesField().get(3));
+    assertEquals(TestUtil.toBytes("44"), message.getInt32ToBytesField().get(4));
+    
+    assertEquals(3, message.getInt32ToEnumField().size());
+    assertEquals(TestMap.EnumValue.BAR, message.getInt32ToEnumField().get(1));
+    assertEquals(TestMap.EnumValue.BAZ, message.getInt32ToEnumField().get(3));
+    assertEquals(TestMap.EnumValue.QUX, message.getInt32ToEnumField().get(4));
+    
+    assertEquals(3, message.getInt32ToMessageField().size());
+    assertEquals(111, message.getInt32ToMessageField().get(1).getValue());
+    assertEquals(33, message.getInt32ToMessageField().get(3).getValue());
+    assertEquals(44, message.getInt32ToMessageField().get(4).getValue());
+    
+    assertEquals(3, message.getStringToInt32Field().size());
+    assertEquals(111, message.getStringToInt32Field().get("1").intValue());
+    assertEquals(33, message.getStringToInt32Field().get("3").intValue());
+    assertEquals(44, message.getStringToInt32Field().get("4").intValue());
+  }
+
+  private void assertMapValuesCleared(TestMap message) {
+    assertEquals(0, message.getInt32ToInt32Field().size());
+    assertEquals(0, message.getInt32ToStringField().size());
+    assertEquals(0, message.getInt32ToBytesField().size());
+    assertEquals(0, message.getInt32ToEnumField().size());
+    assertEquals(0, message.getInt32ToMessageField().size());
+    assertEquals(0, message.getStringToInt32Field().size());
+  }
+
+  public void testGettersAndSetters() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    TestMap message = builder.build();
+    assertMapValuesCleared(message);
+    
+    builder = message.toBuilder();
+    setMapValues(builder);
+    message = builder.build();
+    assertMapValuesSet(message);
+    
+    builder = message.toBuilder();
+    updateMapValues(builder);
+    message = builder.build();
+    assertMapValuesUpdated(message);
+    
+    builder = message.toBuilder();
+    builder.clear();
+    message = builder.build();
+    assertMapValuesCleared(message);
+  }
+
+  public void testSerializeAndParse() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    setMapValues(builder);
+    TestMap message = builder.build();
+    assertEquals(message.getSerializedSize(), message.toByteString().size());
+    message = TestMap.PARSER.parseFrom(message.toByteString());
+    assertMapValuesSet(message);
+    
+    builder = message.toBuilder();
+    updateMapValues(builder);
+    message = builder.build();
+    assertEquals(message.getSerializedSize(), message.toByteString().size());
+    message = TestMap.PARSER.parseFrom(message.toByteString());
+    assertMapValuesUpdated(message);
+    
+    builder = message.toBuilder();
+    builder.clear();
+    message = builder.build();
+    assertEquals(message.getSerializedSize(), message.toByteString().size());
+    message = TestMap.PARSER.parseFrom(message.toByteString());
+    assertMapValuesCleared(message);
+  }
+  
+  public void testMergeFrom() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    setMapValues(builder);
+    TestMap message = builder.build();
+    
+    TestMap.Builder other = TestMap.newBuilder();
+    other.mergeFrom(message);
+    assertMapValuesSet(other.build());
+  }
+
+  public void testEqualsAndHashCode() throws Exception {
+    // Test that generated equals() and hashCode() will disregard the order
+    // of map entries when comparing/hashing map fields.
+    
+    // We can't control the order of elements in a HashMap. The best we can do
+    // here is to add elements in different order.
+    TestMap.Builder b1 = TestMap.newBuilder();
+    b1.getMutableInt32ToInt32Field().put(1, 2);
+    b1.getMutableInt32ToInt32Field().put(3, 4);
+    b1.getMutableInt32ToInt32Field().put(5, 6);
+    TestMap m1 = b1.build();
+    
+    TestMap.Builder b2 = TestMap.newBuilder();
+    b2.getMutableInt32ToInt32Field().put(5, 6);
+    b2.getMutableInt32ToInt32Field().put(1, 2);
+    b2.getMutableInt32ToInt32Field().put(3, 4);
+    TestMap m2 = b2.build();
+    
+    assertEquals(m1, m2);
+    assertEquals(m1.hashCode(), m2.hashCode());
+    
+    // Make sure we did compare map fields.
+    b2.getMutableInt32ToInt32Field().put(1, 0);
+    m2 = b2.build();
+    assertFalse(m1.equals(m2));
+    // Don't check m1.hashCode() != m2.hashCode() because it's not guaranteed
+    // to be different.
+  }
+  
+  
+  public void testNestedBuilderOnChangeEventPropagation() {
+    TestOnChangeEventPropagation.Builder parent =
+        TestOnChangeEventPropagation.newBuilder();
+    parent.getOptionalMessageBuilder().getMutableInt32ToInt32Field().put(1, 2);
+    TestOnChangeEventPropagation message = parent.build();
+    assertEquals(2, message.getOptionalMessage().getInt32ToInt32Field().get(1).intValue());
+    
+    // Make a change using nested builder.
+    parent.getOptionalMessageBuilder().getMutableInt32ToInt32Field().put(1, 3);
+    
+    // Should be able to observe the change.
+    message = parent.build();
+    assertEquals(3, message.getOptionalMessage().getInt32ToInt32Field().get(1).intValue());
+    
+    // Make another change using mergeFrom()
+    TestMap.Builder other = TestMap.newBuilder();
+    other.getMutableInt32ToInt32Field().put(1, 4);
+    parent.getOptionalMessageBuilder().mergeFrom(other.build());
+    
+    // Should be able to observe the change.
+    message = parent.build();
+    assertEquals(4, message.getOptionalMessage().getInt32ToInt32Field().get(1).intValue());
+    
+    // Make yet another change by clearing the nested builder.
+    parent.getOptionalMessageBuilder().clear();
+    
+    // Should be able to observe the change.
+    message = parent.build();
+    assertEquals(0, message.getOptionalMessage().getInt32ToInt32Field().size());
+  }
+  
+  // The following methods are used to test reflection API.
+  
+  private static FieldDescriptor f(String name) {
+    return TestMap.getDescriptor().findFieldByName(name);
+  }
+  
+  private static Object getFieldValue(Message mapEntry, String name) {
+    FieldDescriptor field = mapEntry.getDescriptorForType().findFieldByName(name);
+    return mapEntry.getField(field);
+  }
+  
+  private static Message.Builder setFieldValue(
+      Message.Builder mapEntry, String name, Object value) {
+    FieldDescriptor field = mapEntry.getDescriptorForType().findFieldByName(name);
+    mapEntry.setField(field, value);
+    return mapEntry;
+  }
+  
+  private static void assertHasMapValues(Message message, String name, Map<?, ?> values) {
+    FieldDescriptor field = f(name);
+    for (Object entry : (List<?>) message.getField(field)) {
+      Message mapEntry = (Message) entry;
+      Object key = getFieldValue(mapEntry, "key");
+      Object value = getFieldValue(mapEntry, "value");
+      assertTrue(values.containsKey(key));
+      assertEquals(value, values.get(key));
+    }
+    assertEquals(values.size(), message.getRepeatedFieldCount(field));
+    for (int i = 0; i < message.getRepeatedFieldCount(field); i++) {
+      Message mapEntry = (Message) message.getRepeatedField(field, i);
+      Object key = getFieldValue(mapEntry, "key");
+      Object value = getFieldValue(mapEntry, "value");
+      assertTrue(values.containsKey(key));
+      assertEquals(value, values.get(key));
+    }
+  }
+  
+  private static <KeyType, ValueType>
+  Message newMapEntry(Message.Builder builder, String name, KeyType key, ValueType value) {
+    FieldDescriptor field = builder.getDescriptorForType().findFieldByName(name);
+    Message.Builder entryBuilder = builder.newBuilderForField(field);
+    FieldDescriptor keyField = entryBuilder.getDescriptorForType().findFieldByName("key");
+    FieldDescriptor valueField = entryBuilder.getDescriptorForType().findFieldByName("value");
+    entryBuilder.setField(keyField, key);
+    entryBuilder.setField(valueField, value);
+    return entryBuilder.build();
+  }
+  
+  private static void setMapValues(Message.Builder builder, String name, Map<?, ?> values) {
+    List<Message> entryList = new ArrayList<Message>();
+    for (Map.Entry<?, ?> entry : values.entrySet()) {
+      entryList.add(newMapEntry(builder, name, entry.getKey(), entry.getValue()));
+    }
+    FieldDescriptor field = builder.getDescriptorForType().findFieldByName(name);
+    builder.setField(field, entryList);
+  }
+  
+  private static <KeyType, ValueType>
+  Map<KeyType, ValueType> mapForValues(
+      KeyType key1, ValueType value1, KeyType key2, ValueType value2) {
+    Map<KeyType, ValueType> map = new HashMap<KeyType, ValueType>();
+    map.put(key1, value1);
+    map.put(key2, value2);
+    return map;
+  }
+
+  public void testReflectionApi() throws Exception {
+    // In reflection API, map fields are just repeated message fields.
+    TestMap.Builder builder = TestMap.newBuilder();
+    builder.getMutableInt32ToInt32Field().put(1, 2);
+    builder.getMutableInt32ToInt32Field().put(3, 4);
+    builder.getMutableInt32ToMessageField().put(
+        11, MessageValue.newBuilder().setValue(22).build());
+    builder.getMutableInt32ToMessageField().put(
+        33, MessageValue.newBuilder().setValue(44).build());
+    TestMap message = builder.build();
+
+    // Test getField(), getRepeatedFieldCount(), getRepeatedField().
+    assertHasMapValues(message, "int32_to_int32_field",
+        mapForValues(1, 2, 3, 4));
+    assertHasMapValues(message, "int32_to_message_field",
+        mapForValues(
+            11, MessageValue.newBuilder().setValue(22).build(),
+            33, MessageValue.newBuilder().setValue(44).build()));
+    
+    // Test clearField()
+    builder.clearField(f("int32_to_int32_field"));
+    builder.clearField(f("int32_to_message_field"));
+    message = builder.build();
+    assertEquals(0, message.getInt32ToInt32Field().size());
+    assertEquals(0, message.getInt32ToMessageField().size());
+    
+    // Test setField()
+    setMapValues(builder, "int32_to_int32_field",
+        mapForValues(11, 22, 33, 44));
+    setMapValues(builder, "int32_to_message_field",
+        mapForValues(
+            111, MessageValue.newBuilder().setValue(222).build(),
+            333, MessageValue.newBuilder().setValue(444).build()));
+    message = builder.build();
+    assertEquals(22, message.getInt32ToInt32Field().get(11).intValue());
+    assertEquals(44, message.getInt32ToInt32Field().get(33).intValue());
+    assertEquals(222, message.getInt32ToMessageField().get(111).getValue());
+    assertEquals(444, message.getInt32ToMessageField().get(333).getValue());
+    
+    // Test addRepeatedField
+    builder.addRepeatedField(f("int32_to_int32_field"),
+        newMapEntry(builder, "int32_to_int32_field", 55, 66));
+    builder.addRepeatedField(f("int32_to_message_field"),
+        newMapEntry(builder, "int32_to_message_field", 555,
+            MessageValue.newBuilder().setValue(666).build()));
+    message = builder.build();
+    assertEquals(66, message.getInt32ToInt32Field().get(55).intValue());
+    assertEquals(666, message.getInt32ToMessageField().get(555).getValue());
+
+    // Test addRepeatedField (overriding existing values)
+    builder.addRepeatedField(f("int32_to_int32_field"),
+        newMapEntry(builder, "int32_to_int32_field", 55, 55));
+    builder.addRepeatedField(f("int32_to_message_field"),
+        newMapEntry(builder, "int32_to_message_field", 555,
+            MessageValue.newBuilder().setValue(555).build()));
+    message = builder.build();
+    assertEquals(55, message.getInt32ToInt32Field().get(55).intValue());
+    assertEquals(555, message.getInt32ToMessageField().get(555).getValue());
+    
+    // Test setRepeatedField
+    for (int i = 0; i < builder.getRepeatedFieldCount(f("int32_to_int32_field")); i++) {
+      Message mapEntry = (Message) builder.getRepeatedField(f("int32_to_int32_field"), i);
+      int oldKey = ((Integer) getFieldValue(mapEntry, "key")).intValue();
+      int oldValue = ((Integer) getFieldValue(mapEntry, "value")).intValue();
+      // Swap key with value for each entry.
+      Message.Builder mapEntryBuilder = mapEntry.toBuilder();
+      setFieldValue(mapEntryBuilder, "key", oldValue);
+      setFieldValue(mapEntryBuilder, "value", oldKey);
+      builder.setRepeatedField(f("int32_to_int32_field"), i, mapEntryBuilder.build());
+    }
+    message = builder.build();
+    assertEquals(11, message.getInt32ToInt32Field().get(22).intValue());
+    assertEquals(33, message.getInt32ToInt32Field().get(44).intValue());
+    assertEquals(55, message.getInt32ToInt32Field().get(55).intValue());
+  }
+  
+  public void testTextFormat() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    setMapValues(builder);
+    TestMap message = builder.build();
+    
+    String textData = TextFormat.printToString(message);
+    
+    builder = TestMap.newBuilder();
+    TextFormat.merge(textData, builder);
+    message = builder.build();
+    
+    assertMapValuesSet(message);
+  }
+  
+  public void testDynamicMessage() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    setMapValues(builder);
+    TestMap message = builder.build();
+    
+    Message dynamicDefaultInstance =
+        DynamicMessage.getDefaultInstance(TestMap.getDescriptor());
+    Message dynamicMessage = dynamicDefaultInstance
+        .newBuilderForType().mergeFrom(message.toByteString()).build();
+    
+    assertEquals(message, dynamicMessage);
+    assertEquals(message.hashCode(), dynamicMessage.hashCode());
+  }
+  
+  public void testReflectionEqualsAndHashCode() throws Exception {
+    // Test that generated equals() and hashCode() will disregard the order
+    // of map entries when comparing/hashing map fields.
+
+    // We use DynamicMessage to test reflection based equals()/hashCode().
+    Message dynamicDefaultInstance =
+        DynamicMessage.getDefaultInstance(TestMap.getDescriptor());
+    FieldDescriptor field = f("int32_to_int32_field");
+    
+    Message.Builder b1 = dynamicDefaultInstance.newBuilderForType();
+    b1.addRepeatedField(field, newMapEntry(b1, "int32_to_int32_field", 1, 2));
+    b1.addRepeatedField(field, newMapEntry(b1, "int32_to_int32_field", 3, 4));
+    b1.addRepeatedField(field, newMapEntry(b1, "int32_to_int32_field", 5, 6));
+    Message m1 = b1.build();
+    
+    Message.Builder b2 = dynamicDefaultInstance.newBuilderForType();
+    b2.addRepeatedField(field, newMapEntry(b2, "int32_to_int32_field", 5, 6));
+    b2.addRepeatedField(field, newMapEntry(b2, "int32_to_int32_field", 1, 2));
+    b2.addRepeatedField(field, newMapEntry(b2, "int32_to_int32_field", 3, 4));
+    Message m2 = b2.build();
+    
+    assertEquals(m1, m2);
+    assertEquals(m1.hashCode(), m2.hashCode());
+    
+    // Make sure we did compare map fields.
+    b2.setRepeatedField(field, 0, newMapEntry(b1, "int32_to_int32_field", 0, 0));
+    m2 = b2.build();
+    assertFalse(m1.equals(m2));
+    // Don't check m1.hashCode() != m2.hashCode() because it's not guaranteed
+    // to be different.
+  }
+  
+  public void testUnknownEnumValues() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    builder.getMutableInt32ToEnumFieldValue().put(0, 0);
+    builder.getMutableInt32ToEnumFieldValue().put(1, 1);
+    builder.getMutableInt32ToEnumFieldValue().put(2, 1000);  // unknown value.
+    TestMap message = builder.build();
+
+    assertEquals(TestMap.EnumValue.FOO,
+        message.getInt32ToEnumField().get(0));
+    assertEquals(TestMap.EnumValue.BAR,
+        message.getInt32ToEnumField().get(1));
+    assertEquals(TestMap.EnumValue.UNRECOGNIZED,
+        message.getInt32ToEnumField().get(2));
+    assertEquals(1000, message.getInt32ToEnumFieldValue().get(2).intValue());
+    
+    // Unknown enum values should be preserved after:
+    //   1. Serialization and parsing.
+    //   2. toBuild().
+    //   3. mergeFrom().
+    message = TestMap.parseFrom(message.toByteString());
+    assertEquals(1000, message.getInt32ToEnumFieldValue().get(2).intValue());
+    builder = message.toBuilder();
+    assertEquals(1000, builder.getInt32ToEnumFieldValue().get(2).intValue());
+    builder = TestMap.newBuilder().mergeFrom(message);
+    assertEquals(1000, builder.getInt32ToEnumFieldValue().get(2).intValue());
+    
+    // hashCode()/equals() should take unknown enum values into account.
+    builder.getMutableInt32ToEnumFieldValue().put(2, 1001);
+    TestMap message2 = builder.build();
+    assertFalse(message.hashCode() == message2.hashCode());
+    assertFalse(message.equals(message2));
+    // Unknown values will be converted to UNRECOGNIZED so the resulted enum map
+    // should be the same.
+    assertTrue(message.getInt32ToEnumField().equals(message2.getInt32ToEnumField()));
+  }
+  
+  public void testUnknownEnumValuesInReflectionApi() throws Exception {
+    Descriptor descriptor = TestMap.getDescriptor();
+    EnumDescriptor enumDescriptor = TestMap.EnumValue.getDescriptor();
+    FieldDescriptor field = descriptor.findFieldByName("int32_to_enum_field");
+    
+    Map<Integer, Integer> data = new HashMap<Integer, Integer>();
+    data.put(0, 0);
+    data.put(1, 1);
+    data.put(2, 1000);  // unknown value.
+    
+    TestMap.Builder builder = TestMap.newBuilder();
+    for (Map.Entry<Integer, Integer> entry : data.entrySet()) {
+      builder.getMutableInt32ToEnumFieldValue().put(entry.getKey(), entry.getValue());
+    }
+
+    // Try to read unknown enum values using reflection API.
+    for (int i = 0; i < builder.getRepeatedFieldCount(field); i++) {
+      Message mapEntry = (Message) builder.getRepeatedField(field, i);
+      int key = ((Integer) getFieldValue(mapEntry, "key")).intValue();
+      int value = ((EnumValueDescriptor) getFieldValue(mapEntry, "value")).getNumber();
+      assertEquals(data.get(key).intValue(), value);
+      Message.Builder mapEntryBuilder = mapEntry.toBuilder();
+      // Increase the value by 1.
+      setFieldValue(mapEntryBuilder, "value",
+          enumDescriptor.findValueByNumberCreatingIfUnknown(value + 1));
+      builder.setRepeatedField(field, i, mapEntryBuilder.build());
+    }
+
+    // Verify that enum values have been successfully updated.
+    TestMap message = builder.build();
+    for (Map.Entry<Integer, Integer> entry : message.getInt32ToEnumFieldValue().entrySet()) {
+      assertEquals(data.get(entry.getKey()) + 1, entry.getValue().intValue());
+    }
+  }
+}
diff --git a/java/src/test/java/com/google/protobuf/TestBadIdentifiers.java b/java/src/test/java/com/google/protobuf/TestBadIdentifiers.java
index 614ac7fe..2c60fe0e 100644
--- a/java/src/test/java/com/google/protobuf/TestBadIdentifiers.java
+++ b/java/src/test/java/com/google/protobuf/TestBadIdentifiers.java
@@ -72,7 +72,7 @@ public class TestBadIdentifiers extends TestCase {
     assertEquals(0, message.getMessageField5Count());
 
     assertEquals(0, message.getInt32FieldCount11());
-    assertEquals(1, message.getEnumFieldCount12().getNumber());
+    assertEquals(0, message.getEnumFieldCount12().getNumber());
     assertEquals("", message.getStringFieldCount13());
     assertEquals(ByteString.EMPTY, message.getBytesFieldCount14());
     assertEquals(0, message.getMessageFieldCount15().getSerializedSize());
diff --git a/java/src/test/java/com/google/protobuf/TextFormatTest.java b/java/src/test/java/com/google/protobuf/TextFormatTest.java
index 152bdadc..82f9582f 100644
--- a/java/src/test/java/com/google/protobuf/TextFormatTest.java
+++ b/java/src/test/java/com/google/protobuf/TextFormatTest.java
@@ -73,7 +73,7 @@ public class TextFormatTest extends TestCase {
   private static String exoticText =
     "repeated_int32: -1\n" +
     "repeated_int32: -2147483648\n" +
-    "repeated_int64: -1\n" +
+    "repeated_int64: -1,\n" +
     "repeated_int64: -9223372036854775808\n" +
     "repeated_uint32: 4294967295\n" +
     "repeated_uint32: 2147483648\n" +
@@ -101,7 +101,7 @@ public class TextFormatTest extends TestCase {
 
   private static String canonicalExoticText =
       exoticText.replace(": .", ": 0.").replace(": -.", ": -0.")   // short-form double
-      .replace("23e", "23E").replace("E+", "E").replace("0.23E17", "2.3E16");
+      .replace("23e", "23E").replace("E+", "E").replace("0.23E17", "2.3E16").replace(",", "");
 
   private String messageSetText =
     "[protobuf_unittest.TestMessageSetExtension1] {\n" +
@@ -119,6 +119,7 @@ public class TextFormatTest extends TestCase {
       "  i: 456\n" +
       "}\n";
 
+
   private final TextFormat.Parser parserWithOverwriteForbidden =
       TextFormat.Parser.newBuilder()
           .setSingularOverwritePolicy(
@@ -460,6 +461,7 @@ public class TextFormatTest extends TestCase {
     }
   }
 
+
   private void assertParseErrorWithOverwriteForbidden(String error,
       String text) {
     TestAllTypes.Builder builder = TestAllTypes.newBuilder();
@@ -553,10 +555,10 @@ public class TextFormatTest extends TestCase {
 
   public void testEscape() throws Exception {
     // Escape sequences.
-    assertEquals("\\000\\001\\a\\b\\f\\n\\r\\t\\v\\\\\\'\\\"",
-      TextFormat.escapeBytes(bytes("\0\001\007\b\f\n\r\t\013\\\'\"")));
-    assertEquals("\\000\\001\\a\\b\\f\\n\\r\\t\\v\\\\\\'\\\"",
-      TextFormat.escapeText("\0\001\007\b\f\n\r\t\013\\\'\""));
+    assertEquals("\\000\\001\\a\\b\\f\\n\\r\\t\\v\\\\\\'\\\"\\177",
+      TextFormat.escapeBytes(bytes("\0\001\007\b\f\n\r\t\013\\\'\"\177")));
+    assertEquals("\\000\\001\\a\\b\\f\\n\\r\\t\\v\\\\\\'\\\"\\177",
+      TextFormat.escapeText("\0\001\007\b\f\n\r\t\013\\\'\"\177"));
     assertEquals(bytes("\0\001\007\b\f\n\r\t\013\\\'\""),
       TextFormat.unescapeBytes("\\000\\001\\a\\b\\f\\n\\r\\t\\v\\\\\\'\\\""));
     assertEquals("\0\001\007\b\f\n\r\t\013\\\'\"",
@@ -900,6 +902,7 @@ public class TextFormatTest extends TestCase {
             .build()));
   }
 
+
   public void testParseNonRepeatedFields() throws Exception {
     assertParseSuccessWithOverwriteForbidden(
         "repeated_int32: 1\n" +
diff --git a/java/src/test/java/com/google/protobuf/UnknownEnumValueTest.java b/java/src/test/java/com/google/protobuf/UnknownEnumValueTest.java
new file mode 100644
index 00000000..8f45976f
--- /dev/null
+++ b/java/src/test/java/com/google/protobuf/UnknownEnumValueTest.java
@@ -0,0 +1,255 @@
+// 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.EnumDescriptor;
+import com.google.protobuf.Descriptors.EnumValueDescriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.FieldPresenceTestProto.TestAllTypes;
+import com.google.protobuf.TextFormat.ParseException;
+
+import junit.framework.TestCase;
+
+/**
+ * Unit tests for protos that keep unknown enum values rather than discard
+ * them as unknown fields.
+ */
+public class UnknownEnumValueTest extends TestCase {
+  public void testUnknownEnumValues() throws Exception {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    builder.setOptionalNestedEnumValue(4321);
+    builder.addRepeatedNestedEnumValue(5432);
+    builder.addPackedNestedEnumValue(6543);
+    TestAllTypes message = builder.build();
+    assertEquals(4321, message.getOptionalNestedEnumValue());
+    assertEquals(5432, message.getRepeatedNestedEnumValue(0));
+    assertEquals(5432, message.getRepeatedNestedEnumValueList().get(0).intValue());
+    assertEquals(6543, message.getPackedNestedEnumValue(0));
+    // Returns UNRECOGNIZED if an enum type is requested.
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, message.getOptionalNestedEnum());
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, message.getRepeatedNestedEnum(0));
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, message.getRepeatedNestedEnumList().get(0));
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, message.getPackedNestedEnum(0));
+    
+    // Test serialization and parsing.
+    ByteString data = message.toByteString();
+    message = TestAllTypes.parseFrom(data);
+    assertEquals(4321, message.getOptionalNestedEnumValue());
+    assertEquals(5432, message.getRepeatedNestedEnumValue(0));
+    assertEquals(5432, message.getRepeatedNestedEnumValueList().get(0).intValue());
+    assertEquals(6543, message.getPackedNestedEnumValue(0));
+    // Returns UNRECOGNIZED if an enum type is requested.
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, message.getOptionalNestedEnum());
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, message.getRepeatedNestedEnum(0));
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, message.getRepeatedNestedEnumList().get(0));
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, message.getPackedNestedEnum(0));
+    
+    // Test toBuilder().
+    builder = message.toBuilder();
+    assertEquals(4321, builder.getOptionalNestedEnumValue());
+    assertEquals(5432, builder.getRepeatedNestedEnumValue(0));
+    assertEquals(5432, builder.getRepeatedNestedEnumValueList().get(0).intValue());
+    assertEquals(6543, builder.getPackedNestedEnumValue(0));    
+    // Returns UNRECOGNIZED if an enum type is requested.
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, builder.getOptionalNestedEnum());
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, builder.getRepeatedNestedEnum(0));
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, builder.getRepeatedNestedEnumList().get(0));
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, builder.getPackedNestedEnum(0));
+    
+    // Test mergeFrom().
+    builder = TestAllTypes.newBuilder().mergeFrom(message);
+    assertEquals(4321, builder.getOptionalNestedEnumValue());
+    assertEquals(5432, builder.getRepeatedNestedEnumValue(0));
+    assertEquals(5432, builder.getRepeatedNestedEnumValueList().get(0).intValue());
+    assertEquals(6543, builder.getPackedNestedEnumValue(0));
+    // Returns UNRECOGNIZED if an enum type is requested.
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, builder.getOptionalNestedEnum());
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, builder.getRepeatedNestedEnum(0));
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, builder.getRepeatedNestedEnumList().get(0));
+    assertEquals(TestAllTypes.NestedEnum.UNRECOGNIZED, builder.getPackedNestedEnum(0));
+    
+    // Test equals() and hashCode()
+    TestAllTypes sameMessage = builder.build();
+    assertEquals(message, sameMessage);
+    assertEquals(message.hashCode(), sameMessage.hashCode());
+
+    // Getting the numeric value of UNRECOGNIZED will throw an exception.
+    try {
+      TestAllTypes.NestedEnum.UNRECOGNIZED.getNumber();
+      fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    // Setting an enum field to an UNRECOGNIZED value will throw an exception.
+    try {
+      builder.setOptionalNestedEnum(builder.getOptionalNestedEnum());
+      fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+    try {
+      builder.addRepeatedNestedEnum(builder.getOptionalNestedEnum());
+      fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+  }
+  
+  public void testUnknownEnumValueInReflectionApi() throws Exception {
+    Descriptor descriptor = TestAllTypes.getDescriptor();
+    FieldDescriptor optionalNestedEnumField = descriptor.findFieldByName("optional_nested_enum");
+    FieldDescriptor repeatedNestedEnumField = descriptor.findFieldByName("repeated_nested_enum");
+    FieldDescriptor packedNestedEnumField = descriptor.findFieldByName("packed_nested_enum");
+    EnumDescriptor enumType = TestAllTypes.NestedEnum.getDescriptor();
+
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    builder.setField(optionalNestedEnumField,
+        enumType.findValueByNumberCreatingIfUnknown(4321));
+    builder.addRepeatedField(repeatedNestedEnumField,
+        enumType.findValueByNumberCreatingIfUnknown(5432));
+    builder.addRepeatedField(packedNestedEnumField,
+        enumType.findValueByNumberCreatingIfUnknown(6543));
+    TestAllTypes message = builder.build();
+    
+    // Getters will return unknown enum values as EnumValueDescriptor.
+    EnumValueDescriptor unknown4321 =
+        (EnumValueDescriptor) message.getField(optionalNestedEnumField);
+    EnumValueDescriptor unknown5432 =
+        (EnumValueDescriptor) message.getRepeatedField(repeatedNestedEnumField, 0);
+    EnumValueDescriptor unknown6543 =
+        (EnumValueDescriptor) message.getRepeatedField(packedNestedEnumField, 0);
+    assertEquals(4321, unknown4321.getNumber());
+    assertEquals(5432, unknown5432.getNumber());
+    assertEquals(6543, unknown6543.getNumber());
+    
+    // Unknown EnumValueDescriptor will map to UNRECOGNIZED.
+    assertEquals(
+        TestAllTypes.NestedEnum.valueOf(unknown4321),
+        TestAllTypes.NestedEnum.UNRECOGNIZED);
+    assertEquals(
+        TestAllTypes.NestedEnum.valueOf(unknown5432),
+        TestAllTypes.NestedEnum.UNRECOGNIZED);
+    assertEquals(
+        TestAllTypes.NestedEnum.valueOf(unknown6543),
+        TestAllTypes.NestedEnum.UNRECOGNIZED);
+    
+    // Setters also accept unknown EnumValueDescriptor.
+    builder.setField(optionalNestedEnumField, unknown6543);
+    builder.setRepeatedField(repeatedNestedEnumField, 0, unknown4321);
+    builder.setRepeatedField(packedNestedEnumField, 0, unknown5432);
+    message = builder.build();
+    // Like other descriptors, unknown EnumValueDescriptor can be compared by
+    // object identity.
+    assertTrue(unknown6543 == message.getField(optionalNestedEnumField));
+    assertTrue(unknown4321 == message.getRepeatedField(repeatedNestedEnumField, 0));
+    assertTrue(unknown5432 == message.getRepeatedField(packedNestedEnumField, 0));
+  }
+  
+  public void testUnknownEnumValueWithDynamicMessage() throws Exception {
+    Descriptor descriptor = TestAllTypes.getDescriptor();
+    FieldDescriptor optionalNestedEnumField = descriptor.findFieldByName("optional_nested_enum");
+    FieldDescriptor repeatedNestedEnumField = descriptor.findFieldByName("repeated_nested_enum");
+    FieldDescriptor packedNestedEnumField = descriptor.findFieldByName("packed_nested_enum");
+    EnumDescriptor enumType = TestAllTypes.NestedEnum.getDescriptor();
+    
+    Message dynamicMessageDefaultInstance = DynamicMessage.getDefaultInstance(descriptor);
+
+    Message.Builder builder = dynamicMessageDefaultInstance.newBuilderForType();
+    builder.setField(optionalNestedEnumField,
+        enumType.findValueByNumberCreatingIfUnknown(4321));
+    builder.addRepeatedField(repeatedNestedEnumField,
+        enumType.findValueByNumberCreatingIfUnknown(5432));
+    builder.addRepeatedField(packedNestedEnumField,
+        enumType.findValueByNumberCreatingIfUnknown(6543));
+    Message message = builder.build();
+    assertEquals(4321,
+        ((EnumValueDescriptor) message.getField(optionalNestedEnumField)).getNumber());
+    assertEquals(5432,
+        ((EnumValueDescriptor) message.getRepeatedField(repeatedNestedEnumField, 0)).getNumber());
+    assertEquals(6543,
+        ((EnumValueDescriptor) message.getRepeatedField(packedNestedEnumField, 0)).getNumber());
+    
+    // Test reflection based serialization/parsing implementation.
+    ByteString data = message.toByteString();
+    message = dynamicMessageDefaultInstance
+        .newBuilderForType()
+        .mergeFrom(data)
+        .build();
+    assertEquals(4321,
+        ((EnumValueDescriptor) message.getField(optionalNestedEnumField)).getNumber());
+    assertEquals(5432,
+        ((EnumValueDescriptor) message.getRepeatedField(repeatedNestedEnumField, 0)).getNumber());
+    assertEquals(6543,
+        ((EnumValueDescriptor) message.getRepeatedField(packedNestedEnumField, 0)).getNumber());
+    
+    // Test reflection based equals()/hashCode().
+    builder = dynamicMessageDefaultInstance.newBuilderForType();
+    builder.setField(optionalNestedEnumField,
+        enumType.findValueByNumberCreatingIfUnknown(4321));
+    builder.addRepeatedField(repeatedNestedEnumField,
+        enumType.findValueByNumberCreatingIfUnknown(5432));
+    builder.addRepeatedField(packedNestedEnumField,
+        enumType.findValueByNumberCreatingIfUnknown(6543));
+    Message sameMessage = builder.build();
+    assertEquals(message, sameMessage);
+    assertEquals(message.hashCode(), sameMessage.hashCode());
+    builder.setField(optionalNestedEnumField,
+        enumType.findValueByNumberCreatingIfUnknown(0));
+    Message differentMessage = builder.build();
+    assertFalse(message.equals(differentMessage));
+  }
+  
+  public void testUnknownEnumValuesInTextFormat() {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    builder.setOptionalNestedEnumValue(4321);
+    builder.addRepeatedNestedEnumValue(5432);
+    builder.addPackedNestedEnumValue(6543);
+    TestAllTypes message = builder.build();
+    
+    // We can print a message with unknown enum values.
+    String textData = TextFormat.printToString(message);
+    assertEquals(
+        "optional_nested_enum: UNKNOWN_ENUM_VALUE_NestedEnum_4321\n"
+        + "repeated_nested_enum: UNKNOWN_ENUM_VALUE_NestedEnum_5432\n"
+        + "packed_nested_enum: UNKNOWN_ENUM_VALUE_NestedEnum_6543\n", textData);
+    
+    // Parsing unknown enum values will fail just like parsing other kinds of
+    // unknown fields.
+    try {
+      TextFormat.merge(textData, builder);
+      fail();
+    } catch (ParseException e) {
+      // expected.
+    }
+  }
+}
diff --git a/java/src/test/java/com/google/protobuf/UnknownFieldSetLiteTest.java b/java/src/test/java/com/google/protobuf/UnknownFieldSetLiteTest.java
new file mode 100644
index 00000000..6372b7a7
--- /dev/null
+++ b/java/src/test/java/com/google/protobuf/UnknownFieldSetLiteTest.java
@@ -0,0 +1,317 @@
+// 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 protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.Bar;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.Foo;
+
+import junit.framework.TestCase;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+/**
+ * Tests for {@link UnknownFieldSetLite}.
+ *
+ * @author dweis@google.com (Daniel Weis)
+ */
+public class UnknownFieldSetLiteTest extends TestCase {
+
+  public void testNoDataIsDefaultInstance() {
+    assertSame(
+        UnknownFieldSetLite.getDefaultInstance(),
+        UnknownFieldSetLite.newBuilder()
+            .build());
+  }
+
+  public void testDefaultInstance() {
+    UnknownFieldSetLite unknownFields = UnknownFieldSetLite.getDefaultInstance();
+
+    assertEquals(0, unknownFields.getSerializedSize());
+    assertEquals(ByteString.EMPTY, toByteString(unknownFields));
+  }
+
+  public void testMergeFieldFrom() throws IOException {
+    Foo foo = Foo.newBuilder()
+      .setValue(2)
+      .build();
+
+    CodedInputStream input = CodedInputStream.newInstance(foo.toByteArray());
+
+    UnknownFieldSetLite.Builder builder = UnknownFieldSetLite.newBuilder();
+    builder.mergeFieldFrom(input.readTag(), input);
+
+    assertEquals(foo.toByteString(), toByteString(builder.build()));
+  }
+
+  public void testSerializedSize() throws IOException {
+    Foo foo = Foo.newBuilder()
+      .setValue(2)
+      .build();
+
+    CodedInputStream input = CodedInputStream.newInstance(foo.toByteArray());
+
+    UnknownFieldSetLite.Builder builder = UnknownFieldSetLite.newBuilder();
+    builder.mergeFieldFrom(input.readTag(), input);
+
+    assertEquals(foo.toByteString().size(), builder.build().getSerializedSize());
+  }
+
+  public void testMergeVarintField() throws IOException {
+    UnknownFieldSetLite.Builder builder = UnknownFieldSetLite.newBuilder();
+    builder.mergeVarintField(10, 2);
+
+    CodedInputStream input =
+        CodedInputStream.newInstance(toByteString(builder.build()).toByteArray());
+
+    int tag = input.readTag();
+    assertEquals(10, WireFormat.getTagFieldNumber(tag));
+    assertEquals(WireFormat.WIRETYPE_VARINT, WireFormat.getTagWireType(tag));
+    assertEquals(2, input.readUInt64());
+    assertTrue(input.isAtEnd());
+  }
+
+  public void testMergeVarintField_negative() throws IOException {
+    UnknownFieldSetLite.Builder builder = UnknownFieldSetLite.newBuilder();
+    builder.mergeVarintField(10, -6);
+
+    CodedInputStream input =
+        CodedInputStream.newInstance(toByteString(builder.build()).toByteArray());
+
+    int tag = input.readTag();
+    assertEquals(10, WireFormat.getTagFieldNumber(tag));
+    assertEquals(WireFormat.WIRETYPE_VARINT, WireFormat.getTagWireType(tag));
+    assertEquals(-6, input.readUInt64());
+    assertTrue(input.isAtEnd());
+  }
+
+  public void testEqualsAndHashCode() {
+    UnknownFieldSetLite.Builder builder1 = UnknownFieldSetLite.newBuilder();
+    builder1.mergeVarintField(10, 2);
+    UnknownFieldSetLite unknownFields1 = builder1.build();
+
+    UnknownFieldSetLite.Builder builder2 = UnknownFieldSetLite.newBuilder();
+    builder2.mergeVarintField(10, 2);
+    UnknownFieldSetLite unknownFields2 = builder2.build();
+
+    assertEquals(unknownFields1, unknownFields2);
+    assertEquals(unknownFields1.hashCode(), unknownFields2.hashCode());
+    assertFalse(unknownFields1.equals(UnknownFieldSetLite.getDefaultInstance()));
+    assertFalse(unknownFields1.hashCode() == UnknownFieldSetLite.getDefaultInstance().hashCode());
+  }
+
+  public void testConcat() throws IOException {
+    UnknownFieldSetLite.Builder builder = UnknownFieldSetLite.newBuilder();
+    builder.mergeVarintField(10, 2);
+    UnknownFieldSetLite unknownFields = builder.build();
+
+    unknownFields = UnknownFieldSetLite.concat(unknownFields, unknownFields);
+
+    CodedInputStream input =
+        CodedInputStream.newInstance(toByteString(unknownFields).toByteArray());
+
+    int tag = input.readTag();
+    assertEquals(10, WireFormat.getTagFieldNumber(tag));
+    assertEquals(WireFormat.WIRETYPE_VARINT, WireFormat.getTagWireType(tag));
+    assertEquals(2, input.readUInt64());
+    assertFalse(input.isAtEnd());
+    input.readTag();
+    assertEquals(10, WireFormat.getTagFieldNumber(tag));
+    assertEquals(WireFormat.WIRETYPE_VARINT, WireFormat.getTagWireType(tag));
+    assertEquals(2, input.readUInt64());
+    assertTrue(input.isAtEnd());
+  }
+
+  public void testConcat_empty() {
+    UnknownFieldSetLite unknownFields = UnknownFieldSetLite.concat(
+        UnknownFieldSetLite.getDefaultInstance(), UnknownFieldSetLite.getDefaultInstance());
+
+    assertEquals(0, unknownFields.getSerializedSize());
+    assertEquals(ByteString.EMPTY, toByteString(unknownFields));
+  }
+
+  public void testBuilderReuse() throws IOException {
+    UnknownFieldSetLite.Builder builder = UnknownFieldSetLite.newBuilder();
+    builder.mergeVarintField(10, 2);
+    builder.build();
+
+    try {
+      builder.build();
+      fail();
+    } catch (IllegalStateException e) {
+      // Expected.
+    }
+
+    try {
+      builder.mergeFieldFrom(0, CodedInputStream.newInstance(new byte[0]));
+      fail();
+    } catch (IllegalStateException e) {
+      // Expected.
+    }
+
+    try {
+      builder.mergeVarintField(5, 1);
+      fail();
+    } catch (IllegalStateException e) {
+      // Expected.
+    }
+  }
+
+  public void testBuilderReuse_empty() {
+    UnknownFieldSetLite.Builder builder = UnknownFieldSetLite.newBuilder();
+    builder.build();
+
+    try {
+      builder.build();
+      fail();
+    } catch (IllegalStateException e) {
+      // Expected.
+    }
+  }
+
+  public void testRoundTrips() throws InvalidProtocolBufferException {
+    Foo foo = Foo.newBuilder()
+        .setValue(1)
+        .setExtension(Bar.fooExt, Bar.newBuilder()
+            .setName("name")
+            .build())
+        .setExtension(LiteEqualsAndHash.varint, 22)
+        .setExtension(LiteEqualsAndHash.fixed32, 44)
+        .setExtension(LiteEqualsAndHash.fixed64, 66L)
+        .setExtension(LiteEqualsAndHash.myGroup, LiteEqualsAndHash.MyGroup.newBuilder()
+            .setGroupValue("value")
+            .build())
+        .build();
+
+    Foo copy = Foo.parseFrom(foo.toByteArray());
+
+    assertEquals(foo.getSerializedSize(), copy.getSerializedSize());
+    assertFalse(foo.equals(copy));
+
+    Foo secondCopy = Foo.parseFrom(foo.toByteArray());
+    assertEquals(copy, secondCopy);
+
+    ExtensionRegistryLite extensionRegistry = ExtensionRegistryLite.newInstance();
+    LiteEqualsAndHash.registerAllExtensions(extensionRegistry);
+    Foo copyOfCopy = Foo.parseFrom(copy.toByteArray(), extensionRegistry);
+
+    assertEquals(foo, copyOfCopy);
+  }
+
+  public void testMalformedBytes() {
+    try {
+      Foo.parseFrom("this is a malformed protocol buffer".getBytes(StandardCharsets.UTF_8));
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Expected.
+    }
+  }
+
+  public void testMissingStartGroupTag() throws IOException {
+    ByteString.Output byteStringOutput = ByteString.newOutput();
+    CodedOutputStream output = CodedOutputStream.newInstance(byteStringOutput);
+    output.writeGroupNoTag(Foo.newBuilder().setValue(11).build());
+    output.writeTag(100, WireFormat.WIRETYPE_END_GROUP);
+    output.flush();
+
+    try {
+      Foo.parseFrom(byteStringOutput.toByteString());
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Expected.
+    }
+  }
+
+  public void testMissingEndGroupTag() throws IOException {
+    ByteString.Output byteStringOutput = ByteString.newOutput();
+    CodedOutputStream output = CodedOutputStream.newInstance(byteStringOutput);
+    output.writeTag(100, WireFormat.WIRETYPE_START_GROUP);
+    output.writeGroupNoTag(Foo.newBuilder().setValue(11).build());
+    output.flush();
+
+    try {
+      Foo.parseFrom(byteStringOutput.toByteString());
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Expected.
+    }
+  }
+
+  public void testMismatchingGroupTags() throws IOException {
+    ByteString.Output byteStringOutput = ByteString.newOutput();
+    CodedOutputStream output = CodedOutputStream.newInstance(byteStringOutput);
+    output.writeTag(100, WireFormat.WIRETYPE_START_GROUP);
+    output.writeGroupNoTag(Foo.newBuilder().setValue(11).build());
+    output.writeTag(101, WireFormat.WIRETYPE_END_GROUP);
+    output.flush();
+
+    try {
+      Foo.parseFrom(byteStringOutput.toByteString());
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Expected.
+    }
+  }
+
+  public void testTruncatedInput() {
+    Foo foo = Foo.newBuilder()
+        .setValue(1)
+        .setExtension(Bar.fooExt, Bar.newBuilder()
+            .setName("name")
+            .build())
+        .setExtension(LiteEqualsAndHash.varint, 22)
+        .setExtension(LiteEqualsAndHash.myGroup, LiteEqualsAndHash.MyGroup.newBuilder()
+            .setGroupValue("value")
+            .build())
+        .build();
+
+    try {
+      Foo.parseFrom(foo.toByteString().substring(0, foo.toByteString().size() - 10));
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Expected.
+    }
+  }
+
+  private ByteString toByteString(UnknownFieldSetLite unknownFields) {
+    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+    CodedOutputStream output = CodedOutputStream.newInstance(byteArrayOutputStream);
+    try {
+      unknownFields.writeTo(output);
+      output.flush();
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+    return ByteString.copyFrom(byteArrayOutputStream.toByteArray());
+  }
+}
diff --git a/java/src/test/java/com/google/protobuf/field_presence_test.proto b/java/src/test/java/com/google/protobuf/field_presence_test.proto
new file mode 100644
index 00000000..8d8ea8ef
--- /dev/null
+++ b/java/src/test/java/com/google/protobuf/field_presence_test.proto
@@ -0,0 +1,93 @@
+// 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.
+
+syntax = "proto3";
+
+package field_presence_test;
+
+import "google/protobuf/unittest.proto";
+
+option java_package = "com.google.protobuf";
+option java_outer_classname = "FieldPresenceTestProto";
+option java_generate_equals_and_hash = true;
+
+message TestAllTypes {
+  enum NestedEnum {
+    FOO = 0;
+    BAR = 1;
+    BAZ = 2;
+  }
+  message NestedMessage {
+    optional int32 value = 1;
+  }
+
+  optional int32 optional_int32 = 1;
+  optional string optional_string = 2;
+  optional bytes optional_bytes = 3;
+  optional NestedEnum optional_nested_enum = 4;
+  optional NestedMessage optional_nested_message = 5;
+  optional protobuf_unittest.TestRequired optional_proto2_message = 6;
+
+  oneof oneof_field {
+    int32 oneof_int32 = 11;
+    uint32 oneof_uint32 = 12;
+    string oneof_string = 13;
+    bytes oneof_bytes = 14;
+    NestedEnum oneof_nested_enum = 15;
+    NestedMessage oneof_nested_message = 16;
+    protobuf_unittest.TestRequired oneof_proto2_message = 17;
+  }
+
+  repeated int32 repeated_int32 = 21;
+  repeated string repeated_string = 22;
+  repeated bytes repeated_bytes = 23;
+  repeated NestedEnum repeated_nested_enum = 24;
+  repeated NestedMessage repeated_nested_message = 25;
+  repeated protobuf_unittest.TestRequired repeated_proto2_message = 26;
+  repeated NestedEnum packed_nested_enum = 27 [packed = true];
+}
+
+message TestOptionalFieldsOnly {
+  optional int32 optional_int32 = 1;
+  optional string optional_string = 2;
+  optional bytes optional_bytes = 3;
+  optional TestAllTypes.NestedEnum optional_nested_enum = 4;
+  optional TestAllTypes.NestedMessage optional_nested_message = 5;
+  optional protobuf_unittest.TestRequired optional_proto2_message = 6;
+}
+
+message TestRepeatedFieldsOnly {
+  repeated int32 repeated_int32 = 21;
+  repeated string repeated_string = 22;
+  repeated bytes repeated_bytes = 23;
+  repeated TestAllTypes.NestedEnum repeated_nested_enum = 24;
+  repeated TestAllTypes.NestedMessage repeated_nested_message = 25;
+  repeated protobuf_unittest.TestRequired repeated_proto2_message = 26;
+}
diff --git a/java/src/test/java/com/google/protobuf/lazy_fields_lite.proto b/java/src/test/java/com/google/protobuf/lazy_fields_lite.proto
index baed4e10..015dc267 100644
--- a/java/src/test/java/com/google/protobuf/lazy_fields_lite.proto
+++ b/java/src/test/java/com/google/protobuf/lazy_fields_lite.proto
@@ -32,6 +32,7 @@
 //
 // A proto file with lazy fields
 
+syntax = "proto2";
 
 package protobuf_unittest;
 
diff --git a/java/src/test/java/com/google/protobuf/lite_equals_and_hash.proto b/java/src/test/java/com/google/protobuf/lite_equals_and_hash.proto
index 68615672..86837250 100644
--- a/java/src/test/java/com/google/protobuf/lite_equals_and_hash.proto
+++ b/java/src/test/java/com/google/protobuf/lite_equals_and_hash.proto
@@ -30,6 +30,7 @@
 
 // Author: pbogle@google.com (Phil Bogle)
 
+syntax = "proto2";
 
 package protobuf_unittest.lite_equals_and_hash;
 
@@ -41,9 +42,15 @@ option optimize_for = LITE_RUNTIME;
 message Foo {
   optional int32 value = 1;
   repeated Bar bar = 2;
+
+  extensions 100 to max;
 }
 
 message Bar {
+  extend Foo {
+    optional Bar foo_ext = 100;
+  }
+
   optional string name = 1;
 }
 
@@ -53,3 +60,13 @@ message BarPrime {
 
 message Empty {
 }
+
+extend Foo {
+  optional int32 varint = 101;
+  optional fixed32 fixed32 = 102;
+  optional fixed64 fixed64 = 103;
+  optional group MyGroup = 104 {
+    optional string group_value = 1;
+  }
+}
+
diff --git a/java/src/test/java/com/google/protobuf/map_for_proto2_lite_test.proto b/java/src/test/java/com/google/protobuf/map_for_proto2_lite_test.proto
new file mode 100644
index 00000000..4f23a4a8
--- /dev/null
+++ b/java/src/test/java/com/google/protobuf/map_for_proto2_lite_test.proto
@@ -0,0 +1,63 @@
+// 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.
+
+syntax = "proto2";
+
+
+option java_outer_classname = "MapForProto2TestProto";
+option java_generate_equals_and_hash = true;
+
+message TestMap {
+  message MessageValue {
+    optional int32 value = 1;
+  }
+  enum EnumValue {
+    FOO = 0;
+    BAR = 1;
+    BAZ = 2;
+    QUX = 3;
+  }
+
+  map<int32, int32>         int32_to_int32_field = 1;
+  map<int32, string>        int32_to_string_field = 2;
+  map<int32, bytes>         int32_to_bytes_field = 3;
+  map<int32, EnumValue>     int32_to_enum_field = 4;
+  map<int32, MessageValue>  int32_to_message_field = 5;
+  map<string, int32>        string_to_int32_field = 6;
+}
+
+message TestUnknownEnumValue {
+  // Wire-compatible with TestMap.int32_to_enum_field so we can test the
+  // parsing behavior of TestMap regarding unknown enum values.
+  map<int32, int32> int32_to_int32_field = 4;
+}
+package map_for_proto2_lite_test;
+option java_package = "map_lite_test";
+option optimize_for = LITE_RUNTIME;
diff --git a/java/src/test/java/com/google/protobuf/map_for_proto2_test.proto b/java/src/test/java/com/google/protobuf/map_for_proto2_test.proto
new file mode 100644
index 00000000..36dfbd10
--- /dev/null
+++ b/java/src/test/java/com/google/protobuf/map_for_proto2_test.proto
@@ -0,0 +1,62 @@
+// 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.
+
+syntax = "proto2";
+
+package map_for_proto2_test;
+
+option java_package = "map_test";
+option java_outer_classname = "MapForProto2TestProto";
+option java_generate_equals_and_hash = true;
+
+message TestMap {
+  message MessageValue {
+    optional int32 value = 1;
+  }
+  enum EnumValue {
+    FOO = 0;
+    BAR = 1;
+    BAZ = 2;
+    QUX = 3;
+  }
+
+  map<int32, int32>         int32_to_int32_field = 1;
+  map<int32, string>        int32_to_string_field = 2;
+  map<int32, bytes>         int32_to_bytes_field = 3;
+  map<int32, EnumValue>     int32_to_enum_field = 4;
+  map<int32, MessageValue>  int32_to_message_field = 5;
+  map<string, int32>        string_to_int32_field = 6;
+}
+
+message TestUnknownEnumValue {
+  // Wire-compatible with TestMap.int32_to_enum_field so we can test the
+  // parsing behavior of TestMap regarding unknown enum values.
+  map<int32, int32> int32_to_int32_field = 4;
+}
diff --git a/java/src/test/java/com/google/protobuf/map_test.proto b/java/src/test/java/com/google/protobuf/map_test.proto
new file mode 100644
index 00000000..105ee3f8
--- /dev/null
+++ b/java/src/test/java/com/google/protobuf/map_test.proto
@@ -0,0 +1,63 @@
+// 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.
+
+syntax = "proto3";
+
+package map_test;
+
+option java_package = "map_test";
+option java_outer_classname = "MapTestProto";
+option java_generate_equals_and_hash = true;
+
+message TestMap {
+  message MessageValue {
+    optional int32 value = 1;
+  }
+  enum EnumValue {
+    FOO = 0;
+    BAR = 1;
+    BAZ = 2;
+    QUX = 3;
+  }
+
+  map<int32, int32>        int32_to_int32_field = 1;
+  map<int32, string>       int32_to_string_field = 2;
+  map<int32, bytes>        int32_to_bytes_field = 3;
+  map<int32, EnumValue>    int32_to_enum_field = 4;
+  map<int32, MessageValue> int32_to_message_field = 5;
+  map<string, int32>       string_to_int32_field = 6;
+}
+
+// Used to test that a nested bulider containing map fields will properly
+// propagate the onChange event and mark its parent dirty when a change
+// is made to a map field.
+message TestOnChangeEventPropagation {
+  optional TestMap optional_message = 1;
+}
diff --git a/java/src/test/java/com/google/protobuf/multiple_files_test.proto b/java/src/test/java/com/google/protobuf/multiple_files_test.proto
index 7ec89a05..92790506 100644
--- a/java/src/test/java/com/google/protobuf/multiple_files_test.proto
+++ b/java/src/test/java/com/google/protobuf/multiple_files_test.proto
@@ -32,6 +32,7 @@
 //
 // A proto file which tests the java_multiple_files option.
 
+syntax = "proto2";
 
 // Some generic_services option(s) added automatically.
 // See:  http://go/proto2-generic-services-default
diff --git a/java/src/test/java/com/google/protobuf/nested_builders_test.proto b/java/src/test/java/com/google/protobuf/nested_builders_test.proto
index 8ab4a433..a5dd66d8 100644
--- a/java/src/test/java/com/google/protobuf/nested_builders_test.proto
+++ b/java/src/test/java/com/google/protobuf/nested_builders_test.proto
@@ -30,6 +30,7 @@
 
 // Author: jonp@google.com (Jon Perlow)
 //
+syntax = "proto2";
 
 package protobuf_unittest;
 
diff --git a/java/src/test/java/com/google/protobuf/nested_extension.proto b/java/src/test/java/com/google/protobuf/nested_extension.proto
index 86492867..704e649e 100644
--- a/java/src/test/java/com/google/protobuf/nested_extension.proto
+++ b/java/src/test/java/com/google/protobuf/nested_extension.proto
@@ -33,6 +33,7 @@
 // A proto file with nested extensions. Note that this must be defined in
 // a separate file to properly test the initialization of the outer class.
 
+syntax = "proto2";
 
 import "com/google/protobuf/non_nested_extension.proto";
 
diff --git a/java/src/test/java/com/google/protobuf/nested_extension_lite.proto b/java/src/test/java/com/google/protobuf/nested_extension_lite.proto
index 9c686829..a95c38b2 100644
--- a/java/src/test/java/com/google/protobuf/nested_extension_lite.proto
+++ b/java/src/test/java/com/google/protobuf/nested_extension_lite.proto
@@ -34,6 +34,7 @@
 // this must be defined in a separate file to properly test the initialization
 // of the outer class.
 
+syntax = "proto2";
 
 package protobuf_unittest;
 
diff --git a/java/src/test/java/com/google/protobuf/non_nested_extension.proto b/java/src/test/java/com/google/protobuf/non_nested_extension.proto
index cb2f8b00..31fac552 100644
--- a/java/src/test/java/com/google/protobuf/non_nested_extension.proto
+++ b/java/src/test/java/com/google/protobuf/non_nested_extension.proto
@@ -32,6 +32,7 @@
 //
 // A proto file with extensions.
 
+syntax = "proto2";
 
 package protobuf_unittest;
 
diff --git a/java/src/test/java/com/google/protobuf/non_nested_extension_lite.proto b/java/src/test/java/com/google/protobuf/non_nested_extension_lite.proto
index c1f744b8..37c369ed 100644
--- a/java/src/test/java/com/google/protobuf/non_nested_extension_lite.proto
+++ b/java/src/test/java/com/google/protobuf/non_nested_extension_lite.proto
@@ -32,6 +32,7 @@
 //
 // A proto file with extensions for a MessageLite messages.
 
+syntax = "proto2";
 
 package protobuf_unittest;
 
diff --git a/java/src/test/java/com/google/protobuf/outer_class_name_test.proto b/java/src/test/java/com/google/protobuf/outer_class_name_test.proto
index c5114f89..42083681 100644
--- a/java/src/test/java/com/google/protobuf/outer_class_name_test.proto
+++ b/java/src/test/java/com/google/protobuf/outer_class_name_test.proto
@@ -28,6 +28,8 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+syntax = "proto2";
+
 package protobuf_unittest;
 
 
diff --git a/java/src/test/java/com/google/protobuf/outer_class_name_test2.proto b/java/src/test/java/com/google/protobuf/outer_class_name_test2.proto
index 741cd281..3e5956b0 100644
--- a/java/src/test/java/com/google/protobuf/outer_class_name_test2.proto
+++ b/java/src/test/java/com/google/protobuf/outer_class_name_test2.proto
@@ -28,6 +28,8 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+syntax = "proto2";
+
 package protobuf_unittest;
 
 
diff --git a/java/src/test/java/com/google/protobuf/outer_class_name_test3.proto b/java/src/test/java/com/google/protobuf/outer_class_name_test3.proto
index 5d5d4ac9..74a8ba3c 100644
--- a/java/src/test/java/com/google/protobuf/outer_class_name_test3.proto
+++ b/java/src/test/java/com/google/protobuf/outer_class_name_test3.proto
@@ -28,6 +28,8 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+syntax = "proto2";
+
 package protobuf_unittest;
 
 
diff --git a/java/src/test/java/com/google/protobuf/test_bad_identifiers.proto b/java/src/test/java/com/google/protobuf/test_bad_identifiers.proto
index 202e8c91..67035fd5 100644
--- a/java/src/test/java/com/google/protobuf/test_bad_identifiers.proto
+++ b/java/src/test/java/com/google/protobuf/test_bad_identifiers.proto
@@ -33,6 +33,7 @@
 // This file tests that various identifiers work as field and type names even
 // though the same identifiers are used internally by the java code generator.
 
+syntax = "proto2";
 
 // Some generic_services option(s) added automatically.
 // See:  http://go/proto2-generic-services-default
@@ -59,12 +60,14 @@ message Descriptor {
   }
   optional NestedDescriptor nested_descriptor = 2;
   enum NestedEnum {
+    UNKNOWN = 0;
     FOO = 1;
   }
 }
 
 message Parser {
   enum ParserEnum {
+    UNKNOWN = 0;
     PARSER = 1;
   }
   optional ParserEnum parser = 1;
@@ -72,6 +75,7 @@ message Parser {
 
 message Deprecated {
   enum TestEnum {
+    UNKNOWN = 0;
     FOO = 1;
 
     // Test if @Deprecated annotation conflicts with Deprecated message name.
@@ -118,6 +122,7 @@ service TestConflictingMethodNames {
 
 message TestConflictingFieldNames {
   enum TestEnum {
+    UNKNOWN = 0;
     FOO = 1;
   }
   message TestMessage {
@@ -142,16 +147,23 @@ message TestConflictingFieldNames {
 
   // This field conflicts with "int32_field" as they both generate
   // the method getInt32FieldList().
-  required int32 int32_field_list = 31;
+  required int32 int32_field_list = 31;  // NO_PROTO3
 
-  extensions 1000 to max;
+  extensions 1000 to max;  // NO_PROTO3
 
   repeated int64 int64_field = 41;
-  extend TestConflictingFieldNames {
+  extend TestConflictingFieldNames {  // NO_PROTO3
     // We don't generate accessors for extensions so the following extension
     // fields don't conflict with the repeated field "int64_field".
-    optional int64 int64_field_count = 1001;
-    optional int64 int64_field_list = 1002;
-  }
+    optional int64 int64_field_count = 1001;  // NO_PROTO3
+    optional int64 int64_field_list = 1002;  // NO_PROTO3
+  }  // NO_PROTO3
 }
 
+message TestMapField {
+  message MapField {}
+  message Pair {}
+  message Message {}
+
+  map<int32, int32> map_field = 1;
+}
diff --git a/java/src/test/java/com/google/protobuf/test_check_utf8.proto b/java/src/test/java/com/google/protobuf/test_check_utf8.proto
index 206946d8..119c1dcb 100644
--- a/java/src/test/java/com/google/protobuf/test_check_utf8.proto
+++ b/java/src/test/java/com/google/protobuf/test_check_utf8.proto
@@ -31,6 +31,7 @@
 // Author: Jacob Butcher (jbaum@google.com)
 //
 // Test file option java_string_check_utf8.
+syntax = "proto2";
 
 package proto2_test_check_utf8;
 
diff --git a/java/src/test/java/com/google/protobuf/test_check_utf8_size.proto b/java/src/test/java/com/google/protobuf/test_check_utf8_size.proto
index fa057a88..f06d76d6 100644
--- a/java/src/test/java/com/google/protobuf/test_check_utf8_size.proto
+++ b/java/src/test/java/com/google/protobuf/test_check_utf8_size.proto
@@ -31,6 +31,7 @@
 // Author: Jacob Butcher (jbaum@google.com)
 //
 // Test file option java_string_check_utf8.
+syntax = "proto2";
 
 package proto2_test_check_utf8_size;
 
diff --git a/java/src/test/java/com/google/protobuf/test_custom_options.proto b/java/src/test/java/com/google/protobuf/test_custom_options.proto
index f6a5ecd4..f8efd455 100644
--- a/java/src/test/java/com/google/protobuf/test_custom_options.proto
+++ b/java/src/test/java/com/google/protobuf/test_custom_options.proto
@@ -32,6 +32,7 @@
 //
 // Test that custom options defined in a proto file's dependencies are properly
 // initialized.
+syntax = "proto2";
 
 package protobuf_unittest;
 
diff --git a/java/src/test/java/com/google/protobuf/test_extra_interfaces.proto b/java/src/test/java/com/google/protobuf/test_extra_interfaces.proto
index 72e05a36..645f57b4 100644
--- a/java/src/test/java/com/google/protobuf/test_extra_interfaces.proto
+++ b/java/src/test/java/com/google/protobuf/test_extra_interfaces.proto
@@ -29,6 +29,7 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Author: Darick Tong (darick@google.com)
+syntax = "proto2";
 
 package protobuf_unittest;