Merge tag 'v3.0.1-javalite'

Test: m checkbuild
Change-Id: If5b58ea9b85a243ef67c30b182d7ce748c8eb734

4 files changed, 2202 insertions, 0 deletions

diff --git a/java/util/src/test/java/com/google/protobuf/util/FieldMaskTreeTest.java b/java/util/src/test/java/com/google/protobuf/util/FieldMaskTreeTest.java
new file mode 100644
index 00000000..3ee0fc6e
--- /dev/null
+++ b/java/util/src/test/java/com/google/protobuf/util/FieldMaskTreeTest.java
@@ -0,0 +1,261 @@
+// 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.util;
+
+import protobuf_unittest.UnittestProto.NestedTestAllTypes;
+import protobuf_unittest.UnittestProto.TestAllTypes;
+import protobuf_unittest.UnittestProto.TestAllTypes.NestedMessage;
+
+import junit.framework.TestCase;
+
+public class FieldMaskTreeTest extends TestCase {
+  public void testAddFieldPath() throws Exception {
+    FieldMaskTree tree = new FieldMaskTree();
+    assertEquals("", tree.toString());
+    tree.addFieldPath("");
+    assertEquals("", tree.toString());
+    // New branch.
+    tree.addFieldPath("foo");
+    assertEquals("foo", tree.toString());
+    // Redundant path.
+    tree.addFieldPath("foo");
+    assertEquals("foo", tree.toString());
+    // New branch.
+    tree.addFieldPath("bar.baz");
+    assertEquals("bar.baz,foo", tree.toString());
+    // Redundant sub-path.
+    tree.addFieldPath("foo.bar");
+    assertEquals("bar.baz,foo", tree.toString());
+    // New branch from a non-root node.
+    tree.addFieldPath("bar.quz");
+    assertEquals("bar.baz,bar.quz,foo", tree.toString());
+    // A path that matches several existing sub-paths.
+    tree.addFieldPath("bar");
+    assertEquals("bar,foo", tree.toString());
+  }
+
+  public void testMergeFromFieldMask() throws Exception {
+    FieldMaskTree tree = new FieldMaskTree(FieldMaskUtil.fromString("foo,bar.baz,bar.quz"));
+    assertEquals("bar.baz,bar.quz,foo", tree.toString());
+    tree.mergeFromFieldMask(FieldMaskUtil.fromString("foo.bar,bar"));
+    assertEquals("bar,foo", tree.toString());
+  }
+
+  public void testIntersectFieldPath() throws Exception {
+    FieldMaskTree tree = new FieldMaskTree(FieldMaskUtil.fromString("foo,bar.baz,bar.quz"));
+    FieldMaskTree result = new FieldMaskTree();
+    // Empty path.
+    tree.intersectFieldPath("", result);
+    assertEquals("", result.toString());
+    // Non-exist path.
+    tree.intersectFieldPath("quz", result);
+    assertEquals("", result.toString());
+    // Sub-path of an existing leaf.
+    tree.intersectFieldPath("foo.bar", result);
+    assertEquals("foo.bar", result.toString());
+    // Match an existing leaf node.
+    tree.intersectFieldPath("foo", result);
+    assertEquals("foo", result.toString());
+    // Non-exist path.
+    tree.intersectFieldPath("bar.foo", result);
+    assertEquals("foo", result.toString());
+    // Match a non-leaf node.
+    tree.intersectFieldPath("bar", result);
+    assertEquals("bar.baz,bar.quz,foo", result.toString());
+  }
+
+  public void testMerge() throws Exception {
+    TestAllTypes value =
+        TestAllTypes.newBuilder()
+            .setOptionalInt32(1234)
+            .setOptionalNestedMessage(NestedMessage.newBuilder().setBb(5678))
+            .addRepeatedInt32(4321)
+            .addRepeatedNestedMessage(NestedMessage.newBuilder().setBb(8765))
+            .build();
+    NestedTestAllTypes source =
+        NestedTestAllTypes.newBuilder()
+            .setPayload(value)
+            .setChild(NestedTestAllTypes.newBuilder().setPayload(value))
+            .build();
+    // Now we have a message source with the following structure:
+    //   [root] -+- payload -+- optional_int32
+    //           |           +- optional_nested_message
+    //           |           +- repeated_int32
+    //           |           +- repeated_nested_message
+    //           |
+    //           +- child --- payload -+- optional_int32
+    //                                 +- optional_nested_message
+    //                                 +- repeated_int32
+    //                                 +- repeated_nested_message
+
+    FieldMaskUtil.MergeOptions options = new FieldMaskUtil.MergeOptions();
+
+    // Test merging each individual field.
+    NestedTestAllTypes.Builder builder = NestedTestAllTypes.newBuilder();
+    new FieldMaskTree().addFieldPath("payload.optional_int32").merge(source, builder, options);
+    NestedTestAllTypes.Builder expected = NestedTestAllTypes.newBuilder();
+    expected.getPayloadBuilder().setOptionalInt32(1234);
+    assertEquals(expected.build(), builder.build());
+
+    builder = NestedTestAllTypes.newBuilder();
+    new FieldMaskTree()
+        .addFieldPath("payload.optional_nested_message")
+        .merge(source, builder, options);
+    expected = NestedTestAllTypes.newBuilder();
+    expected.getPayloadBuilder().setOptionalNestedMessage(NestedMessage.newBuilder().setBb(5678));
+    assertEquals(expected.build(), builder.build());
+
+    builder = NestedTestAllTypes.newBuilder();
+    new FieldMaskTree().addFieldPath("payload.repeated_int32").merge(source, builder, options);
+    expected = NestedTestAllTypes.newBuilder();
+    expected.getPayloadBuilder().addRepeatedInt32(4321);
+    assertEquals(expected.build(), builder.build());
+
+    builder = NestedTestAllTypes.newBuilder();
+    new FieldMaskTree()
+        .addFieldPath("payload.repeated_nested_message")
+        .merge(source, builder, options);
+    expected = NestedTestAllTypes.newBuilder();
+    expected.getPayloadBuilder().addRepeatedNestedMessage(NestedMessage.newBuilder().setBb(8765));
+    assertEquals(expected.build(), builder.build());
+
+    builder = NestedTestAllTypes.newBuilder();
+    new FieldMaskTree()
+        .addFieldPath("child.payload.optional_int32")
+        .merge(source, builder, options);
+    expected = NestedTestAllTypes.newBuilder();
+    expected.getChildBuilder().getPayloadBuilder().setOptionalInt32(1234);
+    assertEquals(expected.build(), builder.build());
+
+    builder = NestedTestAllTypes.newBuilder();
+    new FieldMaskTree()
+        .addFieldPath("child.payload.optional_nested_message")
+        .merge(source, builder, options);
+    expected = NestedTestAllTypes.newBuilder();
+    expected
+        .getChildBuilder()
+        .getPayloadBuilder()
+        .setOptionalNestedMessage(NestedMessage.newBuilder().setBb(5678));
+    assertEquals(expected.build(), builder.build());
+
+    builder = NestedTestAllTypes.newBuilder();
+    new FieldMaskTree()
+        .addFieldPath("child.payload.repeated_int32")
+        .merge(source, builder, options);
+    expected = NestedTestAllTypes.newBuilder();
+    expected.getChildBuilder().getPayloadBuilder().addRepeatedInt32(4321);
+    assertEquals(expected.build(), builder.build());
+
+    builder = NestedTestAllTypes.newBuilder();
+    new FieldMaskTree()
+        .addFieldPath("child.payload.repeated_nested_message")
+        .merge(source, builder, options);
+    expected = NestedTestAllTypes.newBuilder();
+    expected
+        .getChildBuilder()
+        .getPayloadBuilder()
+        .addRepeatedNestedMessage(NestedMessage.newBuilder().setBb(8765));
+    assertEquals(expected.build(), builder.build());
+
+    // Test merging all fields.
+    builder = NestedTestAllTypes.newBuilder();
+    new FieldMaskTree()
+        .addFieldPath("child")
+        .addFieldPath("payload")
+        .merge(source, builder, options);
+    assertEquals(source, builder.build());
+
+    // Test repeated options.
+    builder = NestedTestAllTypes.newBuilder();
+    builder.getPayloadBuilder().addRepeatedInt32(1000);
+    new FieldMaskTree().addFieldPath("payload.repeated_int32").merge(source, builder, options);
+    // Default behavior is to append repeated fields.
+    assertEquals(2, builder.getPayload().getRepeatedInt32Count());
+    assertEquals(1000, builder.getPayload().getRepeatedInt32(0));
+    assertEquals(4321, builder.getPayload().getRepeatedInt32(1));
+    // Change to replace repeated fields.
+    options.setReplaceRepeatedFields(true);
+    new FieldMaskTree().addFieldPath("payload.repeated_int32").merge(source, builder, options);
+    assertEquals(1, builder.getPayload().getRepeatedInt32Count());
+    assertEquals(4321, builder.getPayload().getRepeatedInt32(0));
+
+    // Test message options.
+    builder = NestedTestAllTypes.newBuilder();
+    builder.getPayloadBuilder().setOptionalInt32(1000);
+    builder.getPayloadBuilder().setOptionalUint32(2000);
+    new FieldMaskTree().addFieldPath("payload").merge(source, builder, options);
+    // Default behavior is to merge message fields.
+    assertEquals(1234, builder.getPayload().getOptionalInt32());
+    assertEquals(2000, builder.getPayload().getOptionalUint32());
+
+    // Test merging unset message fields.
+    NestedTestAllTypes clearedSource = source.toBuilder().clearPayload().build();
+    builder = NestedTestAllTypes.newBuilder();
+    new FieldMaskTree().addFieldPath("payload").merge(clearedSource, builder, options);
+    assertEquals(false, builder.hasPayload());
+
+    // Change to replace message fields.
+    options.setReplaceMessageFields(true);
+    builder = NestedTestAllTypes.newBuilder();
+    builder.getPayloadBuilder().setOptionalInt32(1000);
+    builder.getPayloadBuilder().setOptionalUint32(2000);
+    new FieldMaskTree().addFieldPath("payload").merge(source, builder, options);
+    assertEquals(1234, builder.getPayload().getOptionalInt32());
+    assertEquals(0, builder.getPayload().getOptionalUint32());
+
+    // Test merging unset message fields.
+    builder = NestedTestAllTypes.newBuilder();
+    builder.getPayloadBuilder().setOptionalInt32(1000);
+    builder.getPayloadBuilder().setOptionalUint32(2000);
+    new FieldMaskTree().addFieldPath("payload").merge(clearedSource, builder, options);
+    assertEquals(false, builder.hasPayload());
+
+    // Test merging unset primitive fields.
+    builder = source.toBuilder();
+    builder.getPayloadBuilder().clearOptionalInt32();
+    NestedTestAllTypes sourceWithPayloadInt32Unset = builder.build();
+    builder = source.toBuilder();
+    new FieldMaskTree()
+        .addFieldPath("payload.optional_int32")
+        .merge(sourceWithPayloadInt32Unset, builder, options);
+    assertEquals(true, builder.getPayload().hasOptionalInt32());
+    assertEquals(0, builder.getPayload().getOptionalInt32());
+
+    // Change to clear unset primitive fields.
+    options.setReplacePrimitiveFields(true);
+    builder = source.toBuilder();
+    new FieldMaskTree()
+        .addFieldPath("payload.optional_int32")
+        .merge(sourceWithPayloadInt32Unset, builder, options);
+    assertEquals(true, builder.hasPayload());
+    assertEquals(false, builder.getPayload().hasOptionalInt32());
+  }
+}
diff --git a/java/util/src/test/java/com/google/protobuf/util/FieldMaskUtilTest.java b/java/util/src/test/java/com/google/protobuf/util/FieldMaskUtilTest.java
new file mode 100644
index 00000000..1a998570
--- /dev/null
+++ b/java/util/src/test/java/com/google/protobuf/util/FieldMaskUtilTest.java
@@ -0,0 +1,213 @@
+// 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.util;
+
+import com.google.protobuf.FieldMask;
+import protobuf_unittest.UnittestProto.NestedTestAllTypes;
+import protobuf_unittest.UnittestProto.TestAllTypes;
+
+import junit.framework.TestCase;
+
+/** Unit tests for {@link FieldMaskUtil}. */
+public class FieldMaskUtilTest extends TestCase {
+  public void testIsValid() throws Exception {
+    assertTrue(FieldMaskUtil.isValid(NestedTestAllTypes.class, "payload"));
+    assertFalse(FieldMaskUtil.isValid(NestedTestAllTypes.class, "nonexist"));
+    assertTrue(FieldMaskUtil.isValid(NestedTestAllTypes.class, "payload.optional_int32"));
+    assertTrue(FieldMaskUtil.isValid(NestedTestAllTypes.class, "payload.repeated_int32"));
+    assertTrue(FieldMaskUtil.isValid(NestedTestAllTypes.class, "payload.optional_nested_message"));
+    assertTrue(FieldMaskUtil.isValid(NestedTestAllTypes.class, "payload.repeated_nested_message"));
+    assertFalse(FieldMaskUtil.isValid(NestedTestAllTypes.class, "payload.nonexist"));
+
+    assertTrue(
+        FieldMaskUtil.isValid(NestedTestAllTypes.class, FieldMaskUtil.fromString("payload")));
+    assertFalse(
+        FieldMaskUtil.isValid(NestedTestAllTypes.class, FieldMaskUtil.fromString("nonexist")));
+    assertFalse(
+        FieldMaskUtil.isValid(
+            NestedTestAllTypes.class, FieldMaskUtil.fromString("payload,nonexist")));
+
+    assertTrue(FieldMaskUtil.isValid(NestedTestAllTypes.getDescriptor(), "payload"));
+    assertFalse(FieldMaskUtil.isValid(NestedTestAllTypes.getDescriptor(), "nonexist"));
+
+    assertTrue(
+        FieldMaskUtil.isValid(
+            NestedTestAllTypes.getDescriptor(), FieldMaskUtil.fromString("payload")));
+    assertFalse(
+        FieldMaskUtil.isValid(
+            NestedTestAllTypes.getDescriptor(), FieldMaskUtil.fromString("nonexist")));
+
+    assertTrue(
+        FieldMaskUtil.isValid(NestedTestAllTypes.class, "payload.optional_nested_message.bb"));
+    // Repeated fields cannot have sub-paths.
+    assertFalse(
+        FieldMaskUtil.isValid(NestedTestAllTypes.class, "payload.repeated_nested_message.bb"));
+    // Non-message fields cannot have sub-paths.
+    assertFalse(FieldMaskUtil.isValid(NestedTestAllTypes.class, "payload.optional_int32.bb"));
+  }
+
+  public void testToString() throws Exception {
+    assertEquals("", FieldMaskUtil.toString(FieldMask.getDefaultInstance()));
+    FieldMask mask = FieldMask.newBuilder().addPaths("foo").build();
+    assertEquals("foo", FieldMaskUtil.toString(mask));
+    mask = FieldMask.newBuilder().addPaths("foo").addPaths("bar").build();
+    assertEquals("foo,bar", FieldMaskUtil.toString(mask));
+
+    // Empty field paths are ignored.
+    mask =
+        FieldMask.newBuilder()
+            .addPaths("")
+            .addPaths("foo")
+            .addPaths("")
+            .addPaths("bar")
+            .addPaths("")
+            .build();
+    assertEquals("foo,bar", FieldMaskUtil.toString(mask));
+  }
+
+  public void testFromString() throws Exception {
+    FieldMask mask = FieldMaskUtil.fromString("");
+    assertEquals(0, mask.getPathsCount());
+    mask = FieldMaskUtil.fromString("foo");
+    assertEquals(1, mask.getPathsCount());
+    assertEquals("foo", mask.getPaths(0));
+    mask = FieldMaskUtil.fromString("foo,bar.baz");
+    assertEquals(2, mask.getPathsCount());
+    assertEquals("foo", mask.getPaths(0));
+    assertEquals("bar.baz", mask.getPaths(1));
+
+    // Empty field paths are ignore.
+    mask = FieldMaskUtil.fromString(",foo,,bar,");
+    assertEquals(2, mask.getPathsCount());
+    assertEquals("foo", mask.getPaths(0));
+    assertEquals("bar", mask.getPaths(1));
+
+    // Check whether the field paths are valid if a class parameter is provided.
+    mask = FieldMaskUtil.fromString(NestedTestAllTypes.class, ",payload");
+
+    try {
+      mask = FieldMaskUtil.fromString(NestedTestAllTypes.class, "payload,nonexist");
+      fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+  }
+
+  public void testFromFieldNumbers() throws Exception {
+    FieldMask mask = FieldMaskUtil.fromFieldNumbers(TestAllTypes.class);
+    assertEquals(0, mask.getPathsCount());
+    mask =
+        FieldMaskUtil.fromFieldNumbers(
+            TestAllTypes.class, TestAllTypes.OPTIONAL_INT32_FIELD_NUMBER);
+    assertEquals(1, mask.getPathsCount());
+    assertEquals("optional_int32", mask.getPaths(0));
+    mask =
+        FieldMaskUtil.fromFieldNumbers(
+            TestAllTypes.class,
+            TestAllTypes.OPTIONAL_INT32_FIELD_NUMBER,
+            TestAllTypes.OPTIONAL_INT64_FIELD_NUMBER);
+    assertEquals(2, mask.getPathsCount());
+    assertEquals("optional_int32", mask.getPaths(0));
+    assertEquals("optional_int64", mask.getPaths(1));
+
+    try {
+      int invalidFieldNumber = 1000;
+      mask = FieldMaskUtil.fromFieldNumbers(TestAllTypes.class, invalidFieldNumber);
+      fail("Exception is expected.");
+    } catch (IllegalArgumentException expected) {
+    }
+  }
+
+  public void testToJsonString() throws Exception {
+    FieldMask mask = FieldMask.getDefaultInstance();
+    assertEquals("", FieldMaskUtil.toJsonString(mask));
+    mask = FieldMask.newBuilder().addPaths("foo").build();
+    assertEquals("foo", FieldMaskUtil.toJsonString(mask));
+    mask = FieldMask.newBuilder().addPaths("foo.bar_baz").addPaths("").build();
+    assertEquals("foo.barBaz", FieldMaskUtil.toJsonString(mask));
+    mask = FieldMask.newBuilder().addPaths("foo").addPaths("bar_baz").build();
+    assertEquals("foo,barBaz", FieldMaskUtil.toJsonString(mask));
+  }
+
+  public void testFromJsonString() throws Exception {
+    FieldMask mask = FieldMaskUtil.fromJsonString("");
+    assertEquals(0, mask.getPathsCount());
+    mask = FieldMaskUtil.fromJsonString("foo");
+    assertEquals(1, mask.getPathsCount());
+    assertEquals("foo", mask.getPaths(0));
+    mask = FieldMaskUtil.fromJsonString("foo.barBaz");
+    assertEquals(1, mask.getPathsCount());
+    assertEquals("foo.bar_baz", mask.getPaths(0));
+    mask = FieldMaskUtil.fromJsonString("foo,barBaz");
+    assertEquals(2, mask.getPathsCount());
+    assertEquals("foo", mask.getPaths(0));
+    assertEquals("bar_baz", mask.getPaths(1));
+  }
+
+  public void testUnion() throws Exception {
+    // Only test a simple case here and expect
+    // {@link FieldMaskTreeTest#testAddFieldPath} to cover all scenarios.
+    FieldMask mask1 = FieldMaskUtil.fromString("foo,bar.baz,bar.quz");
+    FieldMask mask2 = FieldMaskUtil.fromString("foo.bar,bar");
+    FieldMask result = FieldMaskUtil.union(mask1, mask2);
+    assertEquals("bar,foo", FieldMaskUtil.toString(result));
+  }
+
+  public void testUnion_usingVarArgs() throws Exception {
+    FieldMask mask1 = FieldMaskUtil.fromString("foo");
+    FieldMask mask2 = FieldMaskUtil.fromString("foo.bar,bar.quz");
+    FieldMask mask3 = FieldMaskUtil.fromString("bar.quz");
+    FieldMask mask4 = FieldMaskUtil.fromString("bar");
+    FieldMask result = FieldMaskUtil.union(mask1, mask2, mask3, mask4);
+    assertEquals("bar,foo", FieldMaskUtil.toString(result));
+  }
+
+  public void testIntersection() throws Exception {
+    // Only test a simple case here and expect
+    // {@link FieldMaskTreeTest#testIntersectFieldPath} to cover all scenarios.
+    FieldMask mask1 = FieldMaskUtil.fromString("foo,bar.baz,bar.quz");
+    FieldMask mask2 = FieldMaskUtil.fromString("foo.bar,bar");
+    FieldMask result = FieldMaskUtil.intersection(mask1, mask2);
+    assertEquals("bar.baz,bar.quz,foo.bar", FieldMaskUtil.toString(result));
+  }
+
+  public void testMerge() throws Exception {
+    // Only test a simple case here and expect
+    // {@link FieldMaskTreeTest#testMerge} to cover all scenarios.
+    NestedTestAllTypes source =
+        NestedTestAllTypes.newBuilder()
+            .setPayload(TestAllTypes.newBuilder().setOptionalInt32(1234))
+            .build();
+    NestedTestAllTypes.Builder builder = NestedTestAllTypes.newBuilder();
+    FieldMaskUtil.merge(FieldMaskUtil.fromString("payload"), source, builder);
+    assertEquals(1234, builder.getPayload().getOptionalInt32());
+  }
+}
diff --git a/java/util/src/test/java/com/google/protobuf/util/JsonFormatTest.java b/java/util/src/test/java/com/google/protobuf/util/JsonFormatTest.java
new file mode 100644
index 00000000..e68c7be1
--- /dev/null
+++ b/java/util/src/test/java/com/google/protobuf/util/JsonFormatTest.java
@@ -0,0 +1,1227 @@
+// 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.util;
+
+import com.google.protobuf.Any;
+import com.google.protobuf.BoolValue;
+import com.google.protobuf.ByteString;
+import com.google.protobuf.BytesValue;
+import com.google.protobuf.DoubleValue;
+import com.google.protobuf.FloatValue;
+import com.google.protobuf.Int32Value;
+import com.google.protobuf.Int64Value;
+import com.google.protobuf.InvalidProtocolBufferException;
+import com.google.protobuf.ListValue;
+import com.google.protobuf.Message;
+import com.google.protobuf.NullValue;
+import com.google.protobuf.StringValue;
+import com.google.protobuf.Struct;
+import com.google.protobuf.UInt32Value;
+import com.google.protobuf.UInt64Value;
+import com.google.protobuf.Value;
+import com.google.protobuf.util.JsonFormat.TypeRegistry;
+import com.google.protobuf.util.JsonTestProto.TestAllTypes;
+import com.google.protobuf.util.JsonTestProto.TestAllTypes.NestedEnum;
+import com.google.protobuf.util.JsonTestProto.TestAllTypes.NestedMessage;
+import com.google.protobuf.util.JsonTestProto.TestAny;
+import com.google.protobuf.util.JsonTestProto.TestCustomJsonName;
+import com.google.protobuf.util.JsonTestProto.TestDuration;
+import com.google.protobuf.util.JsonTestProto.TestFieldMask;
+import com.google.protobuf.util.JsonTestProto.TestMap;
+import com.google.protobuf.util.JsonTestProto.TestOneof;
+import com.google.protobuf.util.JsonTestProto.TestStruct;
+import com.google.protobuf.util.JsonTestProto.TestTimestamp;
+import com.google.protobuf.util.JsonTestProto.TestWrappers;
+
+import junit.framework.TestCase;
+
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+public class JsonFormatTest extends TestCase {
+  private void setAllFields(TestAllTypes.Builder builder) {
+    builder.setOptionalInt32(1234);
+    builder.setOptionalInt64(1234567890123456789L);
+    builder.setOptionalUint32(5678);
+    builder.setOptionalUint64(2345678901234567890L);
+    builder.setOptionalSint32(9012);
+    builder.setOptionalSint64(3456789012345678901L);
+    builder.setOptionalFixed32(3456);
+    builder.setOptionalFixed64(4567890123456789012L);
+    builder.setOptionalSfixed32(7890);
+    builder.setOptionalSfixed64(5678901234567890123L);
+    builder.setOptionalFloat(1.5f);
+    builder.setOptionalDouble(1.25);
+    builder.setOptionalBool(true);
+    builder.setOptionalString("Hello world!");
+    builder.setOptionalBytes(ByteString.copyFrom(new byte[] {0, 1, 2}));
+    builder.setOptionalNestedEnum(NestedEnum.BAR);
+    builder.getOptionalNestedMessageBuilder().setValue(100);
+
+    builder.addRepeatedInt32(1234);
+    builder.addRepeatedInt64(1234567890123456789L);
+    builder.addRepeatedUint32(5678);
+    builder.addRepeatedUint64(2345678901234567890L);
+    builder.addRepeatedSint32(9012);
+    builder.addRepeatedSint64(3456789012345678901L);
+    builder.addRepeatedFixed32(3456);
+    builder.addRepeatedFixed64(4567890123456789012L);
+    builder.addRepeatedSfixed32(7890);
+    builder.addRepeatedSfixed64(5678901234567890123L);
+    builder.addRepeatedFloat(1.5f);
+    builder.addRepeatedDouble(1.25);
+    builder.addRepeatedBool(true);
+    builder.addRepeatedString("Hello world!");
+    builder.addRepeatedBytes(ByteString.copyFrom(new byte[] {0, 1, 2}));
+    builder.addRepeatedNestedEnum(NestedEnum.BAR);
+    builder.addRepeatedNestedMessageBuilder().setValue(100);
+
+    builder.addRepeatedInt32(234);
+    builder.addRepeatedInt64(234567890123456789L);
+    builder.addRepeatedUint32(678);
+    builder.addRepeatedUint64(345678901234567890L);
+    builder.addRepeatedSint32(012);
+    builder.addRepeatedSint64(456789012345678901L);
+    builder.addRepeatedFixed32(456);
+    builder.addRepeatedFixed64(567890123456789012L);
+    builder.addRepeatedSfixed32(890);
+    builder.addRepeatedSfixed64(678901234567890123L);
+    builder.addRepeatedFloat(11.5f);
+    builder.addRepeatedDouble(11.25);
+    builder.addRepeatedBool(true);
+    builder.addRepeatedString("ello world!");
+    builder.addRepeatedBytes(ByteString.copyFrom(new byte[] {1, 2}));
+    builder.addRepeatedNestedEnum(NestedEnum.BAZ);
+    builder.addRepeatedNestedMessageBuilder().setValue(200);
+  }
+
+  private void assertRoundTripEquals(Message message) throws Exception {
+    assertRoundTripEquals(message, TypeRegistry.getEmptyTypeRegistry());
+  }
+
+  private void assertRoundTripEquals(Message message, TypeRegistry registry) throws Exception {
+    JsonFormat.Printer printer = JsonFormat.printer().usingTypeRegistry(registry);
+    JsonFormat.Parser parser = JsonFormat.parser().usingTypeRegistry(registry);
+    Message.Builder builder = message.newBuilderForType();
+    parser.merge(printer.print(message), builder);
+    Message parsedMessage = builder.build();
+    assertEquals(message.toString(), parsedMessage.toString());
+  }
+
+  private String toJsonString(Message message) throws IOException {
+    return JsonFormat.printer().print(message);
+  }
+  private String toCompactJsonString(Message message) throws IOException{
+    return JsonFormat.printer().omittingInsignificantWhitespace().print(message);
+  }
+
+  private void mergeFromJson(String json, Message.Builder builder) throws IOException {
+    JsonFormat.parser().merge(json, builder);
+  }
+
+  public void testAllFields() throws Exception {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    setAllFields(builder);
+    TestAllTypes message = builder.build();
+
+    assertEquals(
+        "{\n"
+            + "  \"optionalInt32\": 1234,\n"
+            + "  \"optionalInt64\": \"1234567890123456789\",\n"
+            + "  \"optionalUint32\": 5678,\n"
+            + "  \"optionalUint64\": \"2345678901234567890\",\n"
+            + "  \"optionalSint32\": 9012,\n"
+            + "  \"optionalSint64\": \"3456789012345678901\",\n"
+            + "  \"optionalFixed32\": 3456,\n"
+            + "  \"optionalFixed64\": \"4567890123456789012\",\n"
+            + "  \"optionalSfixed32\": 7890,\n"
+            + "  \"optionalSfixed64\": \"5678901234567890123\",\n"
+            + "  \"optionalFloat\": 1.5,\n"
+            + "  \"optionalDouble\": 1.25,\n"
+            + "  \"optionalBool\": true,\n"
+            + "  \"optionalString\": \"Hello world!\",\n"
+            + "  \"optionalBytes\": \"AAEC\",\n"
+            + "  \"optionalNestedMessage\": {\n"
+            + "    \"value\": 100\n"
+            + "  },\n"
+            + "  \"optionalNestedEnum\": \"BAR\",\n"
+            + "  \"repeatedInt32\": [1234, 234],\n"
+            + "  \"repeatedInt64\": [\"1234567890123456789\", \"234567890123456789\"],\n"
+            + "  \"repeatedUint32\": [5678, 678],\n"
+            + "  \"repeatedUint64\": [\"2345678901234567890\", \"345678901234567890\"],\n"
+            + "  \"repeatedSint32\": [9012, 10],\n"
+            + "  \"repeatedSint64\": [\"3456789012345678901\", \"456789012345678901\"],\n"
+            + "  \"repeatedFixed32\": [3456, 456],\n"
+            + "  \"repeatedFixed64\": [\"4567890123456789012\", \"567890123456789012\"],\n"
+            + "  \"repeatedSfixed32\": [7890, 890],\n"
+            + "  \"repeatedSfixed64\": [\"5678901234567890123\", \"678901234567890123\"],\n"
+            + "  \"repeatedFloat\": [1.5, 11.5],\n"
+            + "  \"repeatedDouble\": [1.25, 11.25],\n"
+            + "  \"repeatedBool\": [true, true],\n"
+            + "  \"repeatedString\": [\"Hello world!\", \"ello world!\"],\n"
+            + "  \"repeatedBytes\": [\"AAEC\", \"AQI=\"],\n"
+            + "  \"repeatedNestedMessage\": [{\n"
+            + "    \"value\": 100\n"
+            + "  }, {\n"
+            + "    \"value\": 200\n"
+            + "  }],\n"
+            + "  \"repeatedNestedEnum\": [\"BAR\", \"BAZ\"]\n"
+            + "}",
+        toJsonString(message));
+
+    assertRoundTripEquals(message);
+  }
+
+  public void testUnknownEnumValues() throws Exception {
+    TestAllTypes message =
+        TestAllTypes.newBuilder()
+            .setOptionalNestedEnumValue(12345)
+            .addRepeatedNestedEnumValue(12345)
+            .addRepeatedNestedEnumValue(0)
+            .build();
+    assertEquals(
+        "{\n"
+            + "  \"optionalNestedEnum\": 12345,\n"
+            + "  \"repeatedNestedEnum\": [12345, \"FOO\"]\n"
+            + "}",
+        toJsonString(message));
+    assertRoundTripEquals(message);
+
+    TestMap.Builder mapBuilder = TestMap.newBuilder();
+    mapBuilder.putInt32ToEnumMapValue(1, 0);
+    mapBuilder.getMutableInt32ToEnumMapValue().put(2, 12345);
+    TestMap mapMessage = mapBuilder.build();
+    assertEquals(
+        "{\n"
+            + "  \"int32ToEnumMap\": {\n"
+            + "    \"1\": \"FOO\",\n"
+            + "    \"2\": 12345\n"
+            + "  }\n"
+            + "}",
+        toJsonString(mapMessage));
+    assertRoundTripEquals(mapMessage);
+  }
+
+  public void testSpecialFloatValues() throws Exception {
+    TestAllTypes message =
+        TestAllTypes.newBuilder()
+            .addRepeatedFloat(Float.NaN)
+            .addRepeatedFloat(Float.POSITIVE_INFINITY)
+            .addRepeatedFloat(Float.NEGATIVE_INFINITY)
+            .addRepeatedDouble(Double.NaN)
+            .addRepeatedDouble(Double.POSITIVE_INFINITY)
+            .addRepeatedDouble(Double.NEGATIVE_INFINITY)
+            .build();
+    assertEquals(
+        "{\n"
+            + "  \"repeatedFloat\": [\"NaN\", \"Infinity\", \"-Infinity\"],\n"
+            + "  \"repeatedDouble\": [\"NaN\", \"Infinity\", \"-Infinity\"]\n"
+            + "}",
+        toJsonString(message));
+
+    assertRoundTripEquals(message);
+  }
+
+  public void testParserAcceptStringForNumbericField() throws Exception {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    mergeFromJson(
+        "{\n"
+            + "  \"optionalInt32\": \"1234\",\n"
+            + "  \"optionalUint32\": \"5678\",\n"
+            + "  \"optionalSint32\": \"9012\",\n"
+            + "  \"optionalFixed32\": \"3456\",\n"
+            + "  \"optionalSfixed32\": \"7890\",\n"
+            + "  \"optionalFloat\": \"1.5\",\n"
+            + "  \"optionalDouble\": \"1.25\",\n"
+            + "  \"optionalBool\": \"true\"\n"
+            + "}",
+        builder);
+    TestAllTypes message = builder.build();
+    assertEquals(1234, message.getOptionalInt32());
+    assertEquals(5678, message.getOptionalUint32());
+    assertEquals(9012, message.getOptionalSint32());
+    assertEquals(3456, message.getOptionalFixed32());
+    assertEquals(7890, message.getOptionalSfixed32());
+    assertEquals(1.5f, message.getOptionalFloat());
+    assertEquals(1.25, message.getOptionalDouble());
+    assertEquals(true, message.getOptionalBool());
+  }
+
+  public void testParserAcceptFloatingPointValueForIntegerField() throws Exception {
+    // Test that numeric values like "1.000", "1e5" will also be accepted.
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    mergeFromJson(
+        "{\n"
+            + "  \"repeatedInt32\": [1.000, 1e5, \"1.000\", \"1e5\"],\n"
+            + "  \"repeatedUint32\": [1.000, 1e5, \"1.000\", \"1e5\"],\n"
+            + "  \"repeatedInt64\": [1.000, 1e5, \"1.000\", \"1e5\"],\n"
+            + "  \"repeatedUint64\": [1.000, 1e5, \"1.000\", \"1e5\"]\n"
+            + "}",
+        builder);
+    int[] expectedValues = new int[] {1, 100000, 1, 100000};
+    assertEquals(4, builder.getRepeatedInt32Count());
+    assertEquals(4, builder.getRepeatedUint32Count());
+    assertEquals(4, builder.getRepeatedInt64Count());
+    assertEquals(4, builder.getRepeatedUint64Count());
+    for (int i = 0; i < 4; ++i) {
+      assertEquals(expectedValues[i], builder.getRepeatedInt32(i));
+      assertEquals(expectedValues[i], builder.getRepeatedUint32(i));
+      assertEquals(expectedValues[i], builder.getRepeatedInt64(i));
+      assertEquals(expectedValues[i], builder.getRepeatedUint64(i));
+    }
+
+    // Non-integers will still be rejected.
+    assertRejects("optionalInt32", "1.5");
+    assertRejects("optionalUint32", "1.5");
+    assertRejects("optionalInt64", "1.5");
+    assertRejects("optionalUint64", "1.5");
+  }
+
+  private void assertRejects(String name, String value) {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    try {
+      // Numeric form is rejected.
+      mergeFromJson("{\"" + name + "\":" + value + "}", builder);
+      fail("Exception is expected.");
+    } catch (IOException e) {
+      // Expected.
+    }
+    try {
+      // String form is also rejected.
+      mergeFromJson("{\"" + name + "\":\"" + value + "\"}", builder);
+      fail("Exception is expected.");
+    } catch (IOException e) {
+      // Expected.
+    }
+  }
+
+  private void assertAccepts(String name, String value) throws IOException {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    // Both numeric form and string form are accepted.
+    mergeFromJson("{\"" + name + "\":" + value + "}", builder);
+    builder.clear();
+    mergeFromJson("{\"" + name + "\":\"" + value + "\"}", builder);
+  }
+
+  public void testParserRejectOutOfRangeNumericValues() throws Exception {
+    assertAccepts("optionalInt32", String.valueOf(Integer.MAX_VALUE));
+    assertAccepts("optionalInt32", String.valueOf(Integer.MIN_VALUE));
+    assertRejects("optionalInt32", String.valueOf(Integer.MAX_VALUE + 1L));
+    assertRejects("optionalInt32", String.valueOf(Integer.MIN_VALUE - 1L));
+
+    assertAccepts("optionalUint32", String.valueOf(Integer.MAX_VALUE + 1L));
+    assertRejects("optionalUint32", "123456789012345");
+    assertRejects("optionalUint32", "-1");
+
+    BigInteger one = new BigInteger("1");
+    BigInteger maxLong = new BigInteger(String.valueOf(Long.MAX_VALUE));
+    BigInteger minLong = new BigInteger(String.valueOf(Long.MIN_VALUE));
+    assertAccepts("optionalInt64", maxLong.toString());
+    assertAccepts("optionalInt64", minLong.toString());
+    assertRejects("optionalInt64", maxLong.add(one).toString());
+    assertRejects("optionalInt64", minLong.subtract(one).toString());
+
+    assertAccepts("optionalUint64", maxLong.add(one).toString());
+    assertRejects("optionalUint64", "1234567890123456789012345");
+    assertRejects("optionalUint64", "-1");
+
+    assertAccepts("optionalBool", "true");
+    assertRejects("optionalBool", "1");
+    assertRejects("optionalBool", "0");
+
+    assertAccepts("optionalFloat", String.valueOf(Float.MAX_VALUE));
+    assertAccepts("optionalFloat", String.valueOf(-Float.MAX_VALUE));
+    assertRejects("optionalFloat", String.valueOf(Double.MAX_VALUE));
+    assertRejects("optionalFloat", String.valueOf(-Double.MAX_VALUE));
+
+    BigDecimal moreThanOne = new BigDecimal("1.000001");
+    BigDecimal maxDouble = new BigDecimal(Double.MAX_VALUE);
+    BigDecimal minDouble = new BigDecimal(-Double.MAX_VALUE);
+    assertAccepts("optionalDouble", maxDouble.toString());
+    assertAccepts("optionalDouble", minDouble.toString());
+    assertRejects("optionalDouble", maxDouble.multiply(moreThanOne).toString());
+    assertRejects("optionalDouble", minDouble.multiply(moreThanOne).toString());
+  }
+
+  public void testParserAcceptNull() throws Exception {
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    mergeFromJson(
+        "{\n"
+            + "  \"optionalInt32\": null,\n"
+            + "  \"optionalInt64\": null,\n"
+            + "  \"optionalUint32\": null,\n"
+            + "  \"optionalUint64\": null,\n"
+            + "  \"optionalSint32\": null,\n"
+            + "  \"optionalSint64\": null,\n"
+            + "  \"optionalFixed32\": null,\n"
+            + "  \"optionalFixed64\": null,\n"
+            + "  \"optionalSfixed32\": null,\n"
+            + "  \"optionalSfixed64\": null,\n"
+            + "  \"optionalFloat\": null,\n"
+            + "  \"optionalDouble\": null,\n"
+            + "  \"optionalBool\": null,\n"
+            + "  \"optionalString\": null,\n"
+            + "  \"optionalBytes\": null,\n"
+            + "  \"optionalNestedMessage\": null,\n"
+            + "  \"optionalNestedEnum\": null,\n"
+            + "  \"repeatedInt32\": null,\n"
+            + "  \"repeatedInt64\": null,\n"
+            + "  \"repeatedUint32\": null,\n"
+            + "  \"repeatedUint64\": null,\n"
+            + "  \"repeatedSint32\": null,\n"
+            + "  \"repeatedSint64\": null,\n"
+            + "  \"repeatedFixed32\": null,\n"
+            + "  \"repeatedFixed64\": null,\n"
+            + "  \"repeatedSfixed32\": null,\n"
+            + "  \"repeatedSfixed64\": null,\n"
+            + "  \"repeatedFloat\": null,\n"
+            + "  \"repeatedDouble\": null,\n"
+            + "  \"repeatedBool\": null,\n"
+            + "  \"repeatedString\": null,\n"
+            + "  \"repeatedBytes\": null,\n"
+            + "  \"repeatedNestedMessage\": null,\n"
+            + "  \"repeatedNestedEnum\": null\n"
+            + "}",
+        builder);
+    TestAllTypes message = builder.build();
+    assertEquals(TestAllTypes.getDefaultInstance(), message);
+
+    // Repeated field elements cannot be null.
+    try {
+      builder = TestAllTypes.newBuilder();
+      mergeFromJson("{\n" + "  \"repeatedInt32\": [null, null],\n" + "}", builder);
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Exception expected.
+    }
+
+    try {
+      builder = TestAllTypes.newBuilder();
+      mergeFromJson("{\n" + "  \"repeatedNestedMessage\": [null, null],\n" + "}", builder);
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Exception expected.
+    }
+  }
+
+  public void testNullInOneof() throws Exception {
+    TestOneof.Builder builder = TestOneof.newBuilder();
+    mergeFromJson("{\n" + "  \"oneofNullValue\": null \n" + "}", builder);
+    TestOneof message = builder.build();
+    assertEquals(TestOneof.OneofFieldCase.ONEOF_NULL_VALUE, message.getOneofFieldCase());
+    assertEquals(NullValue.NULL_VALUE, message.getOneofNullValue());
+  }
+
+  public void testParserRejectDuplicatedFields() throws Exception {
+    // TODO(xiaofeng): The parser we are currently using (GSON) will accept and keep the last
+    // one if multiple entries have the same name. This is not the desired behavior but it can
+    // only be fixed by using our own parser. Here we only test the cases where the names are
+    // different but still referring to the same field.
+
+    // Duplicated optional fields.
+    try {
+      TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+      mergeFromJson(
+          "{\n"
+              + "  \"optionalNestedMessage\": {},\n"
+              + "  \"optional_nested_message\": {}\n"
+              + "}",
+          builder);
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Exception expected.
+    }
+
+    // Duplicated repeated fields.
+    try {
+      TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+      mergeFromJson(
+          "{\n"
+              + "  \"repeatedNestedMessage\": [null, null],\n"
+              + "  \"repeated_nested_message\": [null, null]\n"
+              + "}",
+          builder);
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Exception expected.
+    }
+
+    // Duplicated oneof fields.
+    try {
+      TestOneof.Builder builder = TestOneof.newBuilder();
+      mergeFromJson("{\n" + "  \"oneofInt32\": 1,\n" + "  \"oneof_int32\": 2\n" + "}", builder);
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Exception expected.
+    }
+  }
+
+  public void testMapFields() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    builder.putInt32ToInt32Map(1, 10);
+    builder.putInt64ToInt32Map(1234567890123456789L, 10);
+    builder.putUint32ToInt32Map(2, 20);
+    builder.putUint64ToInt32Map(2234567890123456789L, 20);
+    builder.putSint32ToInt32Map(3, 30);
+    builder.putSint64ToInt32Map(3234567890123456789L, 30);
+    builder.putFixed32ToInt32Map(4, 40);
+    builder.putFixed64ToInt32Map(4234567890123456789L, 40);
+    builder.putSfixed32ToInt32Map(5, 50);
+    builder.putSfixed64ToInt32Map(5234567890123456789L, 50);
+    builder.putBoolToInt32Map(false, 6);
+    builder.putStringToInt32Map("Hello", 10);
+
+    builder.putInt32ToInt64Map(1, 1234567890123456789L);
+    builder.putInt32ToUint32Map(2, 20);
+    builder.putInt32ToUint64Map(2, 2234567890123456789L);
+    builder.putInt32ToSint32Map(3, 30);
+    builder.putInt32ToSint64Map(3, 3234567890123456789L);
+    builder.putInt32ToFixed32Map(4, 40);
+    builder.putInt32ToFixed64Map(4, 4234567890123456789L);
+    builder.putInt32ToSfixed32Map(5, 50);
+    builder.putInt32ToSfixed64Map(5, 5234567890123456789L);
+    builder.putInt32ToFloatMap(6, 1.5f);
+    builder.putInt32ToDoubleMap(6, 1.25);
+    builder.putInt32ToBoolMap(7, false);
+    builder.putInt32ToStringMap(7, "World");
+    builder.putInt32ToBytesMap(8, ByteString.copyFrom(new byte[] {1, 2, 3}));
+    builder.putInt32ToMessageMap(8, NestedMessage.newBuilder().setValue(1234).build());
+    builder.putInt32ToEnumMap(9, NestedEnum.BAR);
+    TestMap message = builder.build();
+
+    assertEquals(
+        "{\n"
+            + "  \"int32ToInt32Map\": {\n"
+            + "    \"1\": 10\n"
+            + "  },\n"
+            + "  \"int64ToInt32Map\": {\n"
+            + "    \"1234567890123456789\": 10\n"
+            + "  },\n"
+            + "  \"uint32ToInt32Map\": {\n"
+            + "    \"2\": 20\n"
+            + "  },\n"
+            + "  \"uint64ToInt32Map\": {\n"
+            + "    \"2234567890123456789\": 20\n"
+            + "  },\n"
+            + "  \"sint32ToInt32Map\": {\n"
+            + "    \"3\": 30\n"
+            + "  },\n"
+            + "  \"sint64ToInt32Map\": {\n"
+            + "    \"3234567890123456789\": 30\n"
+            + "  },\n"
+            + "  \"fixed32ToInt32Map\": {\n"
+            + "    \"4\": 40\n"
+            + "  },\n"
+            + "  \"fixed64ToInt32Map\": {\n"
+            + "    \"4234567890123456789\": 40\n"
+            + "  },\n"
+            + "  \"sfixed32ToInt32Map\": {\n"
+            + "    \"5\": 50\n"
+            + "  },\n"
+            + "  \"sfixed64ToInt32Map\": {\n"
+            + "    \"5234567890123456789\": 50\n"
+            + "  },\n"
+            + "  \"boolToInt32Map\": {\n"
+            + "    \"false\": 6\n"
+            + "  },\n"
+            + "  \"stringToInt32Map\": {\n"
+            + "    \"Hello\": 10\n"
+            + "  },\n"
+            + "  \"int32ToInt64Map\": {\n"
+            + "    \"1\": \"1234567890123456789\"\n"
+            + "  },\n"
+            + "  \"int32ToUint32Map\": {\n"
+            + "    \"2\": 20\n"
+            + "  },\n"
+            + "  \"int32ToUint64Map\": {\n"
+            + "    \"2\": \"2234567890123456789\"\n"
+            + "  },\n"
+            + "  \"int32ToSint32Map\": {\n"
+            + "    \"3\": 30\n"
+            + "  },\n"
+            + "  \"int32ToSint64Map\": {\n"
+            + "    \"3\": \"3234567890123456789\"\n"
+            + "  },\n"
+            + "  \"int32ToFixed32Map\": {\n"
+            + "    \"4\": 40\n"
+            + "  },\n"
+            + "  \"int32ToFixed64Map\": {\n"
+            + "    \"4\": \"4234567890123456789\"\n"
+            + "  },\n"
+            + "  \"int32ToSfixed32Map\": {\n"
+            + "    \"5\": 50\n"
+            + "  },\n"
+            + "  \"int32ToSfixed64Map\": {\n"
+            + "    \"5\": \"5234567890123456789\"\n"
+            + "  },\n"
+            + "  \"int32ToFloatMap\": {\n"
+            + "    \"6\": 1.5\n"
+            + "  },\n"
+            + "  \"int32ToDoubleMap\": {\n"
+            + "    \"6\": 1.25\n"
+            + "  },\n"
+            + "  \"int32ToBoolMap\": {\n"
+            + "    \"7\": false\n"
+            + "  },\n"
+            + "  \"int32ToStringMap\": {\n"
+            + "    \"7\": \"World\"\n"
+            + "  },\n"
+            + "  \"int32ToBytesMap\": {\n"
+            + "    \"8\": \"AQID\"\n"
+            + "  },\n"
+            + "  \"int32ToMessageMap\": {\n"
+            + "    \"8\": {\n"
+            + "      \"value\": 1234\n"
+            + "    }\n"
+            + "  },\n"
+            + "  \"int32ToEnumMap\": {\n"
+            + "    \"9\": \"BAR\"\n"
+            + "  }\n"
+            + "}",
+        toJsonString(message));
+    assertRoundTripEquals(message);
+
+    // Test multiple entries.
+    builder = TestMap.newBuilder();
+    builder.putInt32ToInt32Map(1, 2);
+    builder.putInt32ToInt32Map(3, 4);
+    message = builder.build();
+
+    assertEquals(
+        "{\n" + "  \"int32ToInt32Map\": {\n" + "    \"1\": 2,\n" + "    \"3\": 4\n" + "  }\n" + "}",
+        toJsonString(message));
+    assertRoundTripEquals(message);
+  }
+
+  public void testMapNullValueIsRejected() throws Exception {
+    try {
+      TestMap.Builder builder = TestMap.newBuilder();
+      mergeFromJson(
+          "{\n"
+              + "  \"int32ToInt32Map\": {null: 1},\n"
+              + "  \"int32ToMessageMap\": {null: 2}\n"
+              + "}",
+          builder);
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Exception expected.
+    }
+
+    try {
+      TestMap.Builder builder = TestMap.newBuilder();
+      mergeFromJson(
+          "{\n"
+              + "  \"int32ToInt32Map\": {\"1\": null},\n"
+              + "  \"int32ToMessageMap\": {\"2\": null}\n"
+              + "}",
+          builder);
+      fail();
+    } catch (InvalidProtocolBufferException e) {
+      // Exception expected.
+    }
+  }
+
+  public void testParserAcceptNonQuotedObjectKey() throws Exception {
+    TestMap.Builder builder = TestMap.newBuilder();
+    mergeFromJson(
+        "{\n" + "  int32ToInt32Map: {1: 2},\n" + "  stringToInt32Map: {hello: 3}\n" + "}", builder);
+    TestMap message = builder.build();
+    assertEquals(2, message.getInt32ToInt32Map().get(1).intValue());
+    assertEquals(3, message.getStringToInt32Map().get("hello").intValue());
+  }
+
+  public void testWrappers() throws Exception {
+    TestWrappers.Builder builder = TestWrappers.newBuilder();
+    builder.getBoolValueBuilder().setValue(false);
+    builder.getInt32ValueBuilder().setValue(0);
+    builder.getInt64ValueBuilder().setValue(0);
+    builder.getUint32ValueBuilder().setValue(0);
+    builder.getUint64ValueBuilder().setValue(0);
+    builder.getFloatValueBuilder().setValue(0.0f);
+    builder.getDoubleValueBuilder().setValue(0.0);
+    builder.getStringValueBuilder().setValue("");
+    builder.getBytesValueBuilder().setValue(ByteString.EMPTY);
+    TestWrappers message = builder.build();
+
+    assertEquals(
+        "{\n"
+            + "  \"int32Value\": 0,\n"
+            + "  \"uint32Value\": 0,\n"
+            + "  \"int64Value\": \"0\",\n"
+            + "  \"uint64Value\": \"0\",\n"
+            + "  \"floatValue\": 0.0,\n"
+            + "  \"doubleValue\": 0.0,\n"
+            + "  \"boolValue\": false,\n"
+            + "  \"stringValue\": \"\",\n"
+            + "  \"bytesValue\": \"\"\n"
+            + "}",
+        toJsonString(message));
+    assertRoundTripEquals(message);
+
+    builder = TestWrappers.newBuilder();
+    builder.getBoolValueBuilder().setValue(true);
+    builder.getInt32ValueBuilder().setValue(1);
+    builder.getInt64ValueBuilder().setValue(2);
+    builder.getUint32ValueBuilder().setValue(3);
+    builder.getUint64ValueBuilder().setValue(4);
+    builder.getFloatValueBuilder().setValue(5.0f);
+    builder.getDoubleValueBuilder().setValue(6.0);
+    builder.getStringValueBuilder().setValue("7");
+    builder.getBytesValueBuilder().setValue(ByteString.copyFrom(new byte[] {8}));
+    message = builder.build();
+
+    assertEquals(
+        "{\n"
+            + "  \"int32Value\": 1,\n"
+            + "  \"uint32Value\": 3,\n"
+            + "  \"int64Value\": \"2\",\n"
+            + "  \"uint64Value\": \"4\",\n"
+            + "  \"floatValue\": 5.0,\n"
+            + "  \"doubleValue\": 6.0,\n"
+            + "  \"boolValue\": true,\n"
+            + "  \"stringValue\": \"7\",\n"
+            + "  \"bytesValue\": \"CA==\"\n"
+            + "}",
+        toJsonString(message));
+    assertRoundTripEquals(message);
+  }
+
+  public void testTimestamp() throws Exception {
+    TestTimestamp message =
+        TestTimestamp.newBuilder()
+            .setTimestampValue(Timestamps.parse("1970-01-01T00:00:00Z"))
+            .build();
+
+    assertEquals(
+        "{\n" + "  \"timestampValue\": \"1970-01-01T00:00:00Z\"\n" + "}", toJsonString(message));
+    assertRoundTripEquals(message);
+  }
+
+  public void testDuration() throws Exception {
+    TestDuration message =
+        TestDuration.newBuilder().setDurationValue(Durations.parse("12345s")).build();
+
+    assertEquals("{\n" + "  \"durationValue\": \"12345s\"\n" + "}", toJsonString(message));
+    assertRoundTripEquals(message);
+  }
+
+  public void testFieldMask() throws Exception {
+    TestFieldMask message =
+        TestFieldMask.newBuilder()
+            .setFieldMaskValue(FieldMaskUtil.fromString("foo.bar,baz,foo_bar.baz"))
+            .build();
+
+    assertEquals(
+        "{\n" + "  \"fieldMaskValue\": \"foo.bar,baz,fooBar.baz\"\n" + "}", toJsonString(message));
+    assertRoundTripEquals(message);
+  }
+
+  public void testStruct() throws Exception {
+    // Build a struct with all possible values.
+    TestStruct.Builder builder = TestStruct.newBuilder();
+    Struct.Builder structBuilder = builder.getStructValueBuilder();
+    structBuilder.putFields("null_value", Value.newBuilder().setNullValueValue(0).build());
+    structBuilder.putFields("number_value", Value.newBuilder().setNumberValue(1.25).build());
+    structBuilder.putFields("string_value", Value.newBuilder().setStringValue("hello").build());
+    Struct.Builder subStructBuilder = Struct.newBuilder();
+    subStructBuilder.putFields("number_value", Value.newBuilder().setNumberValue(1234).build());
+    structBuilder.putFields(
+        "struct_value", Value.newBuilder().setStructValue(subStructBuilder.build()).build());
+    ListValue.Builder listBuilder = ListValue.newBuilder();
+    listBuilder.addValues(Value.newBuilder().setNumberValue(1.125).build());
+    listBuilder.addValues(Value.newBuilder().setNullValueValue(0).build());
+    structBuilder.putFields(
+        "list_value", Value.newBuilder().setListValue(listBuilder.build()).build());
+    TestStruct message = builder.build();
+
+    assertEquals(
+        "{\n"
+            + "  \"structValue\": {\n"
+            + "    \"null_value\": null,\n"
+            + "    \"number_value\": 1.25,\n"
+            + "    \"string_value\": \"hello\",\n"
+            + "    \"struct_value\": {\n"
+            + "      \"number_value\": 1234.0\n"
+            + "    },\n"
+            + "    \"list_value\": [1.125, null]\n"
+            + "  }\n"
+            + "}",
+        toJsonString(message));
+    assertRoundTripEquals(message);
+
+    builder = TestStruct.newBuilder();
+    builder.setValue(Value.newBuilder().setNullValueValue(0).build());
+    message = builder.build();
+    assertEquals("{\n" + "  \"value\": null\n" + "}", toJsonString(message));
+    assertRoundTripEquals(message);
+
+    builder = TestStruct.newBuilder();
+    listBuilder = builder.getListValueBuilder();
+    listBuilder.addValues(Value.newBuilder().setNumberValue(31831.125).build());
+    listBuilder.addValues(Value.newBuilder().setNullValueValue(0).build());
+    message = builder.build();
+    assertEquals("{\n" + "  \"listValue\": [31831.125, null]\n" + "}", toJsonString(message));
+    assertRoundTripEquals(message);
+  }
+
+  public void testAnyFields() throws Exception {
+    TestAllTypes content = TestAllTypes.newBuilder().setOptionalInt32(1234).build();
+    TestAny message = TestAny.newBuilder().setAnyValue(Any.pack(content)).build();
+
+    // A TypeRegistry must be provided in order to convert Any types.
+    try {
+      toJsonString(message);
+      fail("Exception is expected.");
+    } catch (IOException e) {
+      // Expected.
+    }
+
+    JsonFormat.TypeRegistry registry =
+        JsonFormat.TypeRegistry.newBuilder().add(TestAllTypes.getDescriptor()).build();
+    JsonFormat.Printer printer = JsonFormat.printer().usingTypeRegistry(registry);
+
+    assertEquals(
+        "{\n"
+            + "  \"anyValue\": {\n"
+            + "    \"@type\": \"type.googleapis.com/json_test.TestAllTypes\",\n"
+            + "    \"optionalInt32\": 1234\n"
+            + "  }\n"
+            + "}",
+        printer.print(message));
+    assertRoundTripEquals(message, registry);
+
+    // Well-known types have a special formatting when embedded in Any.
+    //
+    // 1. Any in Any.
+    Any anyMessage = Any.pack(Any.pack(content));
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.Any\",\n"
+            + "  \"value\": {\n"
+            + "    \"@type\": \"type.googleapis.com/json_test.TestAllTypes\",\n"
+            + "    \"optionalInt32\": 1234\n"
+            + "  }\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+
+    // 2. Wrappers in Any.
+    anyMessage = Any.pack(Int32Value.newBuilder().setValue(12345).build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.Int32Value\",\n"
+            + "  \"value\": 12345\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+    anyMessage = Any.pack(UInt32Value.newBuilder().setValue(12345).build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.UInt32Value\",\n"
+            + "  \"value\": 12345\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+    anyMessage = Any.pack(Int64Value.newBuilder().setValue(12345).build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.Int64Value\",\n"
+            + "  \"value\": \"12345\"\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+    anyMessage = Any.pack(UInt64Value.newBuilder().setValue(12345).build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.UInt64Value\",\n"
+            + "  \"value\": \"12345\"\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+    anyMessage = Any.pack(FloatValue.newBuilder().setValue(12345).build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.FloatValue\",\n"
+            + "  \"value\": 12345.0\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+    anyMessage = Any.pack(DoubleValue.newBuilder().setValue(12345).build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.DoubleValue\",\n"
+            + "  \"value\": 12345.0\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+    anyMessage = Any.pack(BoolValue.newBuilder().setValue(true).build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.BoolValue\",\n"
+            + "  \"value\": true\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+    anyMessage = Any.pack(StringValue.newBuilder().setValue("Hello").build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.StringValue\",\n"
+            + "  \"value\": \"Hello\"\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+    anyMessage =
+        Any.pack(BytesValue.newBuilder().setValue(ByteString.copyFrom(new byte[] {1, 2})).build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.BytesValue\",\n"
+            + "  \"value\": \"AQI=\"\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+
+    // 3. Timestamp in Any.
+    anyMessage = Any.pack(Timestamps.parse("1969-12-31T23:59:59Z"));
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.Timestamp\",\n"
+            + "  \"value\": \"1969-12-31T23:59:59Z\"\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+
+    // 4. Duration in Any
+    anyMessage = Any.pack(Durations.parse("12345.10s"));
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.Duration\",\n"
+            + "  \"value\": \"12345.100s\"\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+
+    // 5. FieldMask in Any
+    anyMessage = Any.pack(FieldMaskUtil.fromString("foo.bar,baz"));
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.FieldMask\",\n"
+            + "  \"value\": \"foo.bar,baz\"\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+
+    // 6. Struct in Any
+    Struct.Builder structBuilder = Struct.newBuilder();
+    structBuilder.putFields("number", Value.newBuilder().setNumberValue(1.125).build());
+    anyMessage = Any.pack(structBuilder.build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.Struct\",\n"
+            + "  \"value\": {\n"
+            + "    \"number\": 1.125\n"
+            + "  }\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+    Value.Builder valueBuilder = Value.newBuilder();
+    valueBuilder.setNumberValue(1);
+    anyMessage = Any.pack(valueBuilder.build());
+    assertEquals(
+        "{\n"
+            + "  \"@type\": \"type.googleapis.com/google.protobuf.Value\",\n"
+            + "  \"value\": 1.0\n"
+            + "}",
+        printer.print(anyMessage));
+    assertRoundTripEquals(anyMessage, registry);
+  }
+
+  public void testParserMissingTypeUrl() throws Exception {
+    try {
+      Any.Builder builder = Any.newBuilder();
+      mergeFromJson("{\n" + "  \"optionalInt32\": 1234\n" + "}", builder);
+      fail("Exception is expected.");
+    } catch (IOException e) {
+      // Expected.
+    }
+  }
+
+  public void testParserUnexpectedTypeUrl() throws Exception {
+    try {
+      TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+      mergeFromJson(
+          "{\n"
+              + "  \"@type\": \"type.googleapis.com/json_test.TestAllTypes\",\n"
+              + "  \"optionalInt32\": 12345\n"
+              + "}",
+          builder);
+      fail("Exception is expected.");
+    } catch (IOException e) {
+      // Expected.
+    }
+  }
+
+  public void testParserRejectTrailingComma() throws Exception {
+    try {
+      TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+      mergeFromJson("{\n" + "  \"optionalInt32\": 12345,\n" + "}", builder);
+      fail("Exception is expected.");
+    } catch (IOException e) {
+      // Expected.
+    }
+
+    // TODO(xiaofeng): GSON allows trailing comma in arrays even after I set
+    // the JsonReader to non-lenient mode. If we want to enforce strict JSON
+    // compliance, we might want to switch to a different JSON parser or
+    // implement one by ourselves.
+    // try {
+    //   TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    //   JsonFormat.merge(
+    //       "{\n"
+    //       + "  \"repeatedInt32\": [12345,]\n"
+    //       + "}", builder);
+    //   fail("Exception is expected.");
+    // } catch (IOException e) {
+    //   // Expected.
+    // }
+  }
+
+  public void testParserRejectInvalidBase64() throws Exception {
+    assertRejects("optionalBytes", "!@#$");
+    // We use standard BASE64 with paddings.
+    assertRejects("optionalBytes", "AQI");
+  }
+
+  public void testParserRejectInvalidEnumValue() throws Exception {
+    try {
+      TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+      mergeFromJson("{\n" + "  \"optionalNestedEnum\": \"XXX\"\n" + "}", builder);
+      fail("Exception is expected.");
+    } catch (InvalidProtocolBufferException e) {
+      // Expected.
+    }
+  }
+
+  public void testCustomJsonName() throws Exception {
+    TestCustomJsonName message = TestCustomJsonName.newBuilder().setValue(12345).build();
+    assertEquals("{\n" + "  \"@value\": 12345\n" + "}", JsonFormat.printer().print(message));
+    assertRoundTripEquals(message);
+  }
+
+  public void testDefaultGsonDoesNotHtmlEscape() throws Exception {
+    TestAllTypes message = TestAllTypes.newBuilder().setOptionalString("=").build();
+    assertEquals(
+        "{\n" + "  \"optionalString\": \"=\"" + "\n}", JsonFormat.printer().print(message));
+  }
+
+  public void testIncludingDefaultValueFields() throws Exception {
+    TestAllTypes message = TestAllTypes.getDefaultInstance();
+    assertEquals("{\n}", JsonFormat.printer().print(message));
+    assertEquals(
+        "{\n"
+            + "  \"optionalInt32\": 0,\n"
+            + "  \"optionalInt64\": \"0\",\n"
+            + "  \"optionalUint32\": 0,\n"
+            + "  \"optionalUint64\": \"0\",\n"
+            + "  \"optionalSint32\": 0,\n"
+            + "  \"optionalSint64\": \"0\",\n"
+            + "  \"optionalFixed32\": 0,\n"
+            + "  \"optionalFixed64\": \"0\",\n"
+            + "  \"optionalSfixed32\": 0,\n"
+            + "  \"optionalSfixed64\": \"0\",\n"
+            + "  \"optionalFloat\": 0.0,\n"
+            + "  \"optionalDouble\": 0.0,\n"
+            + "  \"optionalBool\": false,\n"
+            + "  \"optionalString\": \"\",\n"
+            + "  \"optionalBytes\": \"\",\n"
+            + "  \"optionalNestedEnum\": \"FOO\",\n"
+            + "  \"repeatedInt32\": [],\n"
+            + "  \"repeatedInt64\": [],\n"
+            + "  \"repeatedUint32\": [],\n"
+            + "  \"repeatedUint64\": [],\n"
+            + "  \"repeatedSint32\": [],\n"
+            + "  \"repeatedSint64\": [],\n"
+            + "  \"repeatedFixed32\": [],\n"
+            + "  \"repeatedFixed64\": [],\n"
+            + "  \"repeatedSfixed32\": [],\n"
+            + "  \"repeatedSfixed64\": [],\n"
+            + "  \"repeatedFloat\": [],\n"
+            + "  \"repeatedDouble\": [],\n"
+            + "  \"repeatedBool\": [],\n"
+            + "  \"repeatedString\": [],\n"
+            + "  \"repeatedBytes\": [],\n"
+            + "  \"repeatedNestedMessage\": [],\n"
+            + "  \"repeatedNestedEnum\": []\n"
+            + "}",
+        JsonFormat.printer().includingDefaultValueFields().print(message));
+
+    TestMap mapMessage = TestMap.getDefaultInstance();
+    assertEquals("{\n}", JsonFormat.printer().print(mapMessage));
+    assertEquals(
+        "{\n"
+            + "  \"int32ToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"int64ToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"uint32ToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"uint64ToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"sint32ToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"sint64ToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"fixed32ToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"fixed64ToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"sfixed32ToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"sfixed64ToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"boolToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"stringToInt32Map\": {\n"
+            + "  },\n"
+            + "  \"int32ToInt64Map\": {\n"
+            + "  },\n"
+            + "  \"int32ToUint32Map\": {\n"
+            + "  },\n"
+            + "  \"int32ToUint64Map\": {\n"
+            + "  },\n"
+            + "  \"int32ToSint32Map\": {\n"
+            + "  },\n"
+            + "  \"int32ToSint64Map\": {\n"
+            + "  },\n"
+            + "  \"int32ToFixed32Map\": {\n"
+            + "  },\n"
+            + "  \"int32ToFixed64Map\": {\n"
+            + "  },\n"
+            + "  \"int32ToSfixed32Map\": {\n"
+            + "  },\n"
+            + "  \"int32ToSfixed64Map\": {\n"
+            + "  },\n"
+            + "  \"int32ToFloatMap\": {\n"
+            + "  },\n"
+            + "  \"int32ToDoubleMap\": {\n"
+            + "  },\n"
+            + "  \"int32ToBoolMap\": {\n"
+            + "  },\n"
+            + "  \"int32ToStringMap\": {\n"
+            + "  },\n"
+            + "  \"int32ToBytesMap\": {\n"
+            + "  },\n"
+            + "  \"int32ToMessageMap\": {\n"
+            + "  },\n"
+            + "  \"int32ToEnumMap\": {\n"
+            + "  }\n"
+            + "}",
+        JsonFormat.printer().includingDefaultValueFields().print(mapMessage));
+  }
+
+  public void testPreservingProtoFieldNames() throws Exception {
+    TestAllTypes message = TestAllTypes.newBuilder().setOptionalInt32(12345).build();
+    assertEquals("{\n" + "  \"optionalInt32\": 12345\n" + "}", JsonFormat.printer().print(message));
+    assertEquals(
+        "{\n" + "  \"optional_int32\": 12345\n" + "}",
+        JsonFormat.printer().preservingProtoFieldNames().print(message));
+
+    // The json_name field option is ignored when configured to use original proto field names.
+    TestCustomJsonName messageWithCustomJsonName =
+        TestCustomJsonName.newBuilder().setValue(12345).build();
+    assertEquals(
+        "{\n" + "  \"value\": 12345\n" + "}",
+        JsonFormat.printer().preservingProtoFieldNames().print(messageWithCustomJsonName));
+
+    // Parsers accept both original proto field names and lowerCamelCase names.
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    JsonFormat.parser().merge("{\"optionalInt32\": 12345}", builder);
+    assertEquals(12345, builder.getOptionalInt32());
+    builder.clear();
+    JsonFormat.parser().merge("{\"optional_int32\": 54321}", builder);
+    assertEquals(54321, builder.getOptionalInt32());
+  }
+
+  public void testOmittingInsignificantWhiteSpace() throws Exception {
+    TestAllTypes message = TestAllTypes.newBuilder().setOptionalInt32(12345).build();
+    assertEquals("{" + "\"optionalInt32\":12345" + "}", JsonFormat.printer().omittingInsignificantWhitespace().print(message));
+    TestAllTypes message1 = TestAllTypes.getDefaultInstance();
+    assertEquals("{}", JsonFormat.printer().omittingInsignificantWhitespace().print(message1));
+    TestAllTypes.Builder builder = TestAllTypes.newBuilder();
+    setAllFields(builder);
+    TestAllTypes message2 = builder.build();
+    assertEquals(
+        "{"
+            + "\"optionalInt32\":1234,"
+            + "\"optionalInt64\":\"1234567890123456789\","
+            + "\"optionalUint32\":5678,"
+            + "\"optionalUint64\":\"2345678901234567890\","
+            + "\"optionalSint32\":9012,"
+            + "\"optionalSint64\":\"3456789012345678901\","
+            + "\"optionalFixed32\":3456,"
+            + "\"optionalFixed64\":\"4567890123456789012\","
+            + "\"optionalSfixed32\":7890,"
+            + "\"optionalSfixed64\":\"5678901234567890123\","
+            + "\"optionalFloat\":1.5,"
+            + "\"optionalDouble\":1.25,"
+            + "\"optionalBool\":true,"
+            + "\"optionalString\":\"Hello world!\","
+            + "\"optionalBytes\":\"AAEC\","
+            + "\"optionalNestedMessage\":{"
+            + "\"value\":100"
+            + "},"
+            + "\"optionalNestedEnum\":\"BAR\","
+            + "\"repeatedInt32\":[1234,234],"
+            + "\"repeatedInt64\":[\"1234567890123456789\",\"234567890123456789\"],"
+            + "\"repeatedUint32\":[5678,678],"
+            + "\"repeatedUint64\":[\"2345678901234567890\",\"345678901234567890\"],"
+            + "\"repeatedSint32\":[9012,10],"
+            + "\"repeatedSint64\":[\"3456789012345678901\",\"456789012345678901\"],"
+            + "\"repeatedFixed32\":[3456,456],"
+            + "\"repeatedFixed64\":[\"4567890123456789012\",\"567890123456789012\"],"
+            + "\"repeatedSfixed32\":[7890,890],"
+            + "\"repeatedSfixed64\":[\"5678901234567890123\",\"678901234567890123\"],"
+            + "\"repeatedFloat\":[1.5,11.5],"
+            + "\"repeatedDouble\":[1.25,11.25],"
+            + "\"repeatedBool\":[true,true],"
+            + "\"repeatedString\":[\"Hello world!\",\"ello world!\"],"
+            + "\"repeatedBytes\":[\"AAEC\",\"AQI=\"],"
+            + "\"repeatedNestedMessage\":[{"
+            + "\"value\":100"
+            + "},{"
+            + "\"value\":200"
+            + "}],"
+            + "\"repeatedNestedEnum\":[\"BAR\",\"BAZ\"]"
+            + "}",
+        toCompactJsonString(message2));
+  }
+
+}
diff --git a/java/util/src/test/java/com/google/protobuf/util/TimeUtilTest.java b/java/util/src/test/java/com/google/protobuf/util/TimeUtilTest.java
new file mode 100644
index 00000000..a41528ec
--- /dev/null
+++ b/java/util/src/test/java/com/google/protobuf/util/TimeUtilTest.java
@@ -0,0 +1,501 @@
+// 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.util;
+
+import com.google.protobuf.Duration;
+import com.google.protobuf.Timestamp;
+
+import junit.framework.TestCase;
+
+import org.junit.Assert;
+
+import java.text.ParseException;
+import java.util.ArrayList;
+import java.util.List;
+
+/** Unit tests for {@link TimeUtil}. */
+public class TimeUtilTest extends TestCase {
+  public void testTimestampStringFormat() throws Exception {
+    Timestamp start = TimeUtil.parseTimestamp("0001-01-01T00:00:00Z");
+    Timestamp end = TimeUtil.parseTimestamp("9999-12-31T23:59:59.999999999Z");
+    assertEquals(TimeUtil.TIMESTAMP_SECONDS_MIN, start.getSeconds());
+    assertEquals(0, start.getNanos());
+    assertEquals(TimeUtil.TIMESTAMP_SECONDS_MAX, end.getSeconds());
+    assertEquals(999999999, end.getNanos());
+    assertEquals("0001-01-01T00:00:00Z", TimeUtil.toString(start));
+    assertEquals("9999-12-31T23:59:59.999999999Z", TimeUtil.toString(end));
+
+    Timestamp value = TimeUtil.parseTimestamp("1970-01-01T00:00:00Z");
+    assertEquals(0, value.getSeconds());
+    assertEquals(0, value.getNanos());
+
+    // Test negative timestamps.
+    value = TimeUtil.parseTimestamp("1969-12-31T23:59:59.999Z");
+    assertEquals(-1, value.getSeconds());
+    // Nano part is in the range of [0, 999999999] for Timestamp.
+    assertEquals(999000000, value.getNanos());
+
+    // Test that 3, 6, or 9 digits are used for the fractional part.
+    value = Timestamp.newBuilder().setNanos(10).build();
+    assertEquals("1970-01-01T00:00:00.000000010Z", TimeUtil.toString(value));
+    value = Timestamp.newBuilder().setNanos(10000).build();
+    assertEquals("1970-01-01T00:00:00.000010Z", TimeUtil.toString(value));
+    value = Timestamp.newBuilder().setNanos(10000000).build();
+    assertEquals("1970-01-01T00:00:00.010Z", TimeUtil.toString(value));
+
+    // Test that parsing accepts timezone offsets.
+    value = TimeUtil.parseTimestamp("1970-01-01T00:00:00.010+08:00");
+    assertEquals("1969-12-31T16:00:00.010Z", TimeUtil.toString(value));
+    value = TimeUtil.parseTimestamp("1970-01-01T00:00:00.010-08:00");
+    assertEquals("1970-01-01T08:00:00.010Z", TimeUtil.toString(value));
+  }
+
+  private volatile boolean stopParsingThreads = false;
+  private volatile String errorMessage = "";
+
+  private class ParseTimestampThread extends Thread {
+    private final String[] strings;
+    private final Timestamp[] values;
+
+    public ParseTimestampThread(String[] strings, Timestamp[] values) {
+      this.strings = strings;
+      this.values = values;
+    }
+
+    @Override
+    public void run() {
+      int index = 0;
+      while (!stopParsingThreads) {
+        Timestamp result;
+        try {
+          result = TimeUtil.parseTimestamp(strings[index]);
+        } catch (ParseException e) {
+          errorMessage = "Failed to parse timestamp: " + strings[index];
+          break;
+        }
+        if (result.getSeconds() != values[index].getSeconds()
+            || result.getNanos() != values[index].getNanos()) {
+          errorMessage =
+              "Actual result: " + result.toString() + ", expected: " + values[index].toString();
+          break;
+        }
+        index = (index + 1) % strings.length;
+      }
+    }
+  }
+
+  public void testTimestampConcurrentParsing() throws Exception {
+    String[] timestampStrings =
+        new String[] {
+          "0001-01-01T00:00:00Z",
+          "9999-12-31T23:59:59.999999999Z",
+          "1970-01-01T00:00:00Z",
+          "1969-12-31T23:59:59.999Z",
+        };
+    Timestamp[] timestampValues = new Timestamp[timestampStrings.length];
+    for (int i = 0; i < timestampStrings.length; i++) {
+      timestampValues[i] = TimeUtil.parseTimestamp(timestampStrings[i]);
+    }
+
+    final int THREAD_COUNT = 16;
+    final int RUNNING_TIME = 5000; // in milliseconds.
+    final List<Thread> threads = new ArrayList<Thread>();
+
+    stopParsingThreads = false;
+    errorMessage = "";
+    for (int i = 0; i < THREAD_COUNT; i++) {
+      Thread thread = new ParseTimestampThread(timestampStrings, timestampValues);
+      thread.start();
+      threads.add(thread);
+    }
+    Thread.sleep(RUNNING_TIME);
+    stopParsingThreads = true;
+    for (Thread thread : threads) {
+      thread.join();
+    }
+    Assert.assertEquals("", errorMessage);
+  }
+
+  public void testTimetampInvalidFormat() throws Exception {
+    try {
+      // Value too small.
+      Timestamp value =
+          Timestamp.newBuilder().setSeconds(TimeUtil.TIMESTAMP_SECONDS_MIN - 1).build();
+      TimeUtil.toString(value);
+      Assert.fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    try {
+      // Value too large.
+      Timestamp value =
+          Timestamp.newBuilder().setSeconds(TimeUtil.TIMESTAMP_SECONDS_MAX + 1).build();
+      TimeUtil.toString(value);
+      Assert.fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    try {
+      // Invalid nanos value.
+      Timestamp value = Timestamp.newBuilder().setNanos(-1).build();
+      TimeUtil.toString(value);
+      Assert.fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    try {
+      // Invalid nanos value.
+      Timestamp value = Timestamp.newBuilder().setNanos(1000000000).build();
+      TimeUtil.toString(value);
+      Assert.fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    try {
+      // Value to small.
+      TimeUtil.parseTimestamp("0000-01-01T00:00:00Z");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Value to large.
+      TimeUtil.parseTimestamp("10000-01-01T00:00:00Z");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Missing 'T'.
+      TimeUtil.parseTimestamp("1970-01-01 00:00:00Z");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Missing 'Z'.
+      TimeUtil.parseTimestamp("1970-01-01T00:00:00");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Invalid offset.
+      TimeUtil.parseTimestamp("1970-01-01T00:00:00+0000");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Trailing text.
+      TimeUtil.parseTimestamp("1970-01-01T00:00:00Z0");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Invalid nanosecond value.
+      TimeUtil.parseTimestamp("1970-01-01T00:00:00.ABCZ");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+  }
+
+  public void testDurationStringFormat() throws Exception {
+    Timestamp start = TimeUtil.parseTimestamp("0001-01-01T00:00:00Z");
+    Timestamp end = TimeUtil.parseTimestamp("9999-12-31T23:59:59.999999999Z");
+    Duration duration = TimeUtil.distance(start, end);
+    assertEquals("315537897599.999999999s", TimeUtil.toString(duration));
+    duration = TimeUtil.distance(end, start);
+    assertEquals("-315537897599.999999999s", TimeUtil.toString(duration));
+
+    // Generated output should contain 3, 6, or 9 fractional digits.
+    duration = Duration.newBuilder().setSeconds(1).build();
+    assertEquals("1s", TimeUtil.toString(duration));
+    duration = Duration.newBuilder().setNanos(10000000).build();
+    assertEquals("0.010s", TimeUtil.toString(duration));
+    duration = Duration.newBuilder().setNanos(10000).build();
+    assertEquals("0.000010s", TimeUtil.toString(duration));
+    duration = Duration.newBuilder().setNanos(10).build();
+    assertEquals("0.000000010s", TimeUtil.toString(duration));
+
+    // Parsing accepts an fractional digits as long as they fit into nano
+    // precision.
+    duration = TimeUtil.parseDuration("0.1s");
+    assertEquals(100000000, duration.getNanos());
+    duration = TimeUtil.parseDuration("0.0001s");
+    assertEquals(100000, duration.getNanos());
+    duration = TimeUtil.parseDuration("0.0000001s");
+    assertEquals(100, duration.getNanos());
+
+    // Duration must support range from -315,576,000,000s to +315576000000s
+    // which includes negative values.
+    duration = TimeUtil.parseDuration("315576000000.999999999s");
+    assertEquals(315576000000L, duration.getSeconds());
+    assertEquals(999999999, duration.getNanos());
+    duration = TimeUtil.parseDuration("-315576000000.999999999s");
+    assertEquals(-315576000000L, duration.getSeconds());
+    assertEquals(-999999999, duration.getNanos());
+  }
+
+  public void testDurationInvalidFormat() throws Exception {
+    try {
+      // Value too small.
+      Duration value = Duration.newBuilder().setSeconds(TimeUtil.DURATION_SECONDS_MIN - 1).build();
+      TimeUtil.toString(value);
+      Assert.fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    try {
+      // Value too large.
+      Duration value = Duration.newBuilder().setSeconds(TimeUtil.DURATION_SECONDS_MAX + 1).build();
+      TimeUtil.toString(value);
+      Assert.fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    try {
+      // Invalid nanos value.
+      Duration value = Duration.newBuilder().setSeconds(1).setNanos(-1).build();
+      TimeUtil.toString(value);
+      Assert.fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    try {
+      // Invalid nanos value.
+      Duration value = Duration.newBuilder().setSeconds(-1).setNanos(1).build();
+      TimeUtil.toString(value);
+      Assert.fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    try {
+      // Value too small.
+      TimeUtil.parseDuration("-315576000001s");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Value too large.
+      TimeUtil.parseDuration("315576000001s");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Empty.
+      TimeUtil.parseDuration("");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Missing "s".
+      TimeUtil.parseDuration("0");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Invalid trailing data.
+      TimeUtil.parseDuration("0s0");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+
+    try {
+      // Invalid prefix.
+      TimeUtil.parseDuration("--1s");
+      Assert.fail("Exception is expected.");
+    } catch (ParseException e) {
+      // Expected.
+    }
+  }
+
+  public void testTimestampConversion() throws Exception {
+    Timestamp timestamp = TimeUtil.parseTimestamp("1970-01-01T00:00:01.111111111Z");
+    assertEquals(1111111111, TimeUtil.toNanos(timestamp));
+    assertEquals(1111111, TimeUtil.toMicros(timestamp));
+    assertEquals(1111, TimeUtil.toMillis(timestamp));
+    timestamp = TimeUtil.createTimestampFromNanos(1111111111);
+    assertEquals("1970-01-01T00:00:01.111111111Z", TimeUtil.toString(timestamp));
+    timestamp = TimeUtil.createTimestampFromMicros(1111111);
+    assertEquals("1970-01-01T00:00:01.111111Z", TimeUtil.toString(timestamp));
+    timestamp = TimeUtil.createTimestampFromMillis(1111);
+    assertEquals("1970-01-01T00:00:01.111Z", TimeUtil.toString(timestamp));
+
+    timestamp = TimeUtil.parseTimestamp("1969-12-31T23:59:59.111111111Z");
+    assertEquals(-888888889, TimeUtil.toNanos(timestamp));
+    assertEquals(-888889, TimeUtil.toMicros(timestamp));
+    assertEquals(-889, TimeUtil.toMillis(timestamp));
+    timestamp = TimeUtil.createTimestampFromNanos(-888888889);
+    assertEquals("1969-12-31T23:59:59.111111111Z", TimeUtil.toString(timestamp));
+    timestamp = TimeUtil.createTimestampFromMicros(-888889);
+    assertEquals("1969-12-31T23:59:59.111111Z", TimeUtil.toString(timestamp));
+    timestamp = TimeUtil.createTimestampFromMillis(-889);
+    assertEquals("1969-12-31T23:59:59.111Z", TimeUtil.toString(timestamp));
+  }
+
+  public void testDurationConversion() throws Exception {
+    Duration duration = TimeUtil.parseDuration("1.111111111s");
+    assertEquals(1111111111, TimeUtil.toNanos(duration));
+    assertEquals(1111111, TimeUtil.toMicros(duration));
+    assertEquals(1111, TimeUtil.toMillis(duration));
+    duration = TimeUtil.createDurationFromNanos(1111111111);
+    assertEquals("1.111111111s", TimeUtil.toString(duration));
+    duration = TimeUtil.createDurationFromMicros(1111111);
+    assertEquals("1.111111s", TimeUtil.toString(duration));
+    duration = TimeUtil.createDurationFromMillis(1111);
+    assertEquals("1.111s", TimeUtil.toString(duration));
+
+    duration = TimeUtil.parseDuration("-1.111111111s");
+    assertEquals(-1111111111, TimeUtil.toNanos(duration));
+    assertEquals(-1111111, TimeUtil.toMicros(duration));
+    assertEquals(-1111, TimeUtil.toMillis(duration));
+    duration = TimeUtil.createDurationFromNanos(-1111111111);
+    assertEquals("-1.111111111s", TimeUtil.toString(duration));
+    duration = TimeUtil.createDurationFromMicros(-1111111);
+    assertEquals("-1.111111s", TimeUtil.toString(duration));
+    duration = TimeUtil.createDurationFromMillis(-1111);
+    assertEquals("-1.111s", TimeUtil.toString(duration));
+  }
+
+  public void testTimeOperations() throws Exception {
+    Timestamp start = TimeUtil.parseTimestamp("0001-01-01T00:00:00Z");
+    Timestamp end = TimeUtil.parseTimestamp("9999-12-31T23:59:59.999999999Z");
+
+    Duration duration = TimeUtil.distance(start, end);
+    assertEquals("315537897599.999999999s", TimeUtil.toString(duration));
+    Timestamp value = TimeUtil.add(start, duration);
+    assertEquals(end, value);
+    value = TimeUtil.subtract(end, duration);
+    assertEquals(start, value);
+
+    duration = TimeUtil.distance(end, start);
+    assertEquals("-315537897599.999999999s", TimeUtil.toString(duration));
+    value = TimeUtil.add(end, duration);
+    assertEquals(start, value);
+    value = TimeUtil.subtract(start, duration);
+    assertEquals(end, value);
+
+    // Result is larger than Long.MAX_VALUE.
+    try {
+      duration = TimeUtil.parseDuration("315537897599.999999999s");
+      duration = TimeUtil.multiply(duration, 315537897599.999999999);
+      Assert.fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    // Result is lesser than Long.MIN_VALUE.
+    try {
+      duration = TimeUtil.parseDuration("315537897599.999999999s");
+      duration = TimeUtil.multiply(duration, -315537897599.999999999);
+      Assert.fail("Exception is expected.");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+
+    duration = TimeUtil.parseDuration("-1.125s");
+    duration = TimeUtil.divide(duration, 2.0);
+    assertEquals("-0.562500s", TimeUtil.toString(duration));
+    duration = TimeUtil.multiply(duration, 2.0);
+    assertEquals("-1.125s", TimeUtil.toString(duration));
+
+    duration = TimeUtil.add(duration, duration);
+    assertEquals("-2.250s", TimeUtil.toString(duration));
+
+    duration = TimeUtil.subtract(duration, TimeUtil.parseDuration("-1s"));
+    assertEquals("-1.250s", TimeUtil.toString(duration));
+
+    // Multiplications (with results larger than Long.MAX_VALUE in nanoseconds).
+    duration = TimeUtil.parseDuration("0.999999999s");
+    assertEquals(
+        "315575999684.424s", TimeUtil.toString(TimeUtil.multiply(duration, 315576000000L)));
+    duration = TimeUtil.parseDuration("-0.999999999s");
+    assertEquals(
+        "-315575999684.424s", TimeUtil.toString(TimeUtil.multiply(duration, 315576000000L)));
+    assertEquals(
+        "315575999684.424s", TimeUtil.toString(TimeUtil.multiply(duration, -315576000000L)));
+
+    // Divisions (with values larger than Long.MAX_VALUE in nanoseconds).
+    Duration d1 = TimeUtil.parseDuration("315576000000s");
+    Duration d2 = TimeUtil.subtract(d1, TimeUtil.createDurationFromNanos(1));
+    assertEquals(1, TimeUtil.divide(d1, d2));
+    assertEquals(0, TimeUtil.divide(d2, d1));
+    assertEquals("0.000000001s", TimeUtil.toString(TimeUtil.remainder(d1, d2)));
+    assertEquals("315575999999.999999999s", TimeUtil.toString(TimeUtil.remainder(d2, d1)));
+
+    // Divisions involving negative values.
+    //
+    // (-5) / 2 = -2, remainder = -1
+    d1 = TimeUtil.parseDuration("-5s");
+    d2 = TimeUtil.parseDuration("2s");
+    assertEquals(-2, TimeUtil.divide(d1, d2));
+    assertEquals(-2, TimeUtil.divide(d1, 2).getSeconds());
+    assertEquals(-1, TimeUtil.remainder(d1, d2).getSeconds());
+    // (-5) / (-2) = 2, remainder = -1
+    d1 = TimeUtil.parseDuration("-5s");
+    d2 = TimeUtil.parseDuration("-2s");
+    assertEquals(2, TimeUtil.divide(d1, d2));
+    assertEquals(2, TimeUtil.divide(d1, -2).getSeconds());
+    assertEquals(-1, TimeUtil.remainder(d1, d2).getSeconds());
+    // 5 / (-2) = -2, remainder = 1
+    d1 = TimeUtil.parseDuration("5s");
+    d2 = TimeUtil.parseDuration("-2s");
+    assertEquals(-2, TimeUtil.divide(d1, d2));
+    assertEquals(-2, TimeUtil.divide(d1, -2).getSeconds());
+    assertEquals(1, TimeUtil.remainder(d1, d2).getSeconds());
+  }
+}