Prepare nano proto code to be merged into protobuf repository.

35 files changed, 9522 insertions, 0 deletions

diff --git a/javanano/README.txt b/javanano/README.txt
new file mode 100644
index 00000000..fae32927
--- /dev/null
+++ b/javanano/README.txt
@@ -0,0 +1,354 @@
+Protocol Buffers - Google's data interchange format
+Copyright 2008 Google Inc.
+
+This directory contains the Java Protocol Buffers Nano runtime library.
+
+Installation - With Maven
+=========================
+
+The Protocol Buffers build is managed using Maven.  If you would
+rather build without Maven, see below.
+
+1) Install Apache Maven if you don't have it:
+
+     http://maven.apache.org/
+
+2) Build the C++ code, or obtain a binary distribution of protoc.  If
+   you install a binary distribution, make sure that it is the same
+   version as this package.  If in doubt, run:
+
+     $ protoc --version
+
+   You will need to place the protoc executable in ../src.  (If you
+   built it yourself, it should already be there.)
+
+3) Run the tests:
+
+     $ mvn test
+
+   If some tests fail, this library may not work correctly on your
+   system.  Continue at your own risk.
+
+4) Install the library into your Maven repository:
+
+     $ mvn install
+
+5) If you do not use Maven to manage your own build, you can build a
+   .jar file to use:
+
+     $ mvn package
+
+   The .jar will be placed in the "target" directory.
+
+Installation - Without Maven
+============================
+
+If you would rather not install Maven to build the library, you may
+follow these instructions instead.  Note that these instructions skip
+running unit tests.
+
+1) Build the C++ code, or obtain a binary distribution of protoc.  If
+   you install a binary distribution, make sure that it is the same
+   version as this package.  If in doubt, run:
+
+     $ protoc --version
+
+   If you built the C++ code without installing, the compiler binary
+   should be located in ../src.
+
+2) Invoke protoc to build DescriptorProtos.java:
+
+     $ protoc --java_out=src/main/java -I../src \
+         ../src/google/protobuf/descriptor.proto
+
+3) Compile the code in src/main/java using whatever means you prefer.
+
+4) Install the classes wherever you prefer.
+
+Nano version
+============================
+
+Nano is a special code generator and runtime library designed specially
+for Android, and is very resource-friendly in both the amount of code
+and the runtime overhead. An overview of Nano features:
+
+- No descriptors or message builders.
+- All messages are mutable; fields are public Java fields.
+- For optional fields only, encapsulation behind setter/getter/hazzer/
+  clearer functions is opt-in, which provide proper 'has' state support.
+- If not opted in, has state is not available. Serialization outputs
+  all fields not equal to their defaults (see important implications
+  below).
+- Required fields are always serialized.
+- Enum constants are integers; protection against invalid values only
+  when parsing from the wire.
+- Enum constants can be generated into container interfaces bearing
+  the enum's name (so the referencing code is in Java style).
+- CodedInputByteBufferNano can only take byte[] (not InputStream).
+- Similarly CodedOutputByteBufferNano can only write to byte[].
+- Repeated fields are in arrays, not ArrayList or Vector. Null array
+  elements are allowed and silently ignored.
+- Full support of serializing/deserializing repeated packed fields.
+- Support of extensions.
+- Unset messages/groups are null, not an immutable empty default
+  instance.
+- toByteArray(...) and mergeFrom(...) are now static functions of
+  MessageNano.
+- The 'bytes' type translates to the Java type byte[].
+
+The generated messages are not thread-safe for writes, but may be
+used simultaneously from multiple threads in a read-only manner.
+In other words, an appropriate synchronization mechanism (such as
+a ReadWriteLock) must be used to ensure that a message, its
+ancestors, and descendants are not accessed by any other threads
+while the message is being modified. Field reads, getter methods
+(but not getExtension(...)), toByteArray(...), writeTo(...),
+getCachedSize(), and getSerializedSize() are all considered read-only
+operations.
+
+IMPORTANT: If you have fields with defaults and opt out of accessors
+
+How fields with defaults are serialized has changed. Because we don't
+keep "has" state, any field equal to its default is assumed to be not
+set and therefore is not serialized. Consider the situation where we
+change the default value of a field. Senders compiled against an older
+version of the proto continue to match against the old default, and
+don't send values to the receiver even though the receiver assumes the
+new default value. Therefore, think carefully about the implications
+of changing the default value. Alternatively, turn on accessors and
+enjoy the benefit of the explicit has() checks.
+
+IMPORTANT: If you have "bytes" fields with non-empty defaults
+
+Because the byte buffer is now of mutable type byte[], the default
+static final cannot be exposed through a public field. Each time a
+message's constructor or clear() function is called, the default value
+(kept in a private byte[]) is cloned. This causes a small memory
+penalty. This is not a problem if the field has no default or is an
+empty default.
+
+Nano Generator options
+
+java_package           -> <file-name>|<package-name>
+java_outer_classname   -> <file-name>|<package-name>
+java_multiple_files    -> true or false
+java_nano_generate_has -> true or false [DEPRECATED]
+optional_field_style   -> default or accessors
+enum_style             -> c or java
+ignore_services        -> true or false
+parcelable_messages    -> true or false
+
+java_package=<file-name>|<package-name> (no default)
+  This allows overriding the 'java_package' option value
+  for the given file from the command line. Use multiple
+  java_package options to override the option for multiple
+  files. The final Java package for each file is the value
+  of this command line option if present, or the value of
+  the same option defined in the file if present, or the
+  proto package if present, or the default Java package.
+
+java_outer_classname=<file-name>|<outer-classname> (no default)
+  This allows overriding the 'java_outer_classname' option
+  for the given file from the command line. Use multiple
+  java_outer_classname options to override the option for
+  multiple files. The final Java outer class name for each
+  file is the value of this command line option if present,
+  or the value of the same option defined in the file if
+  present, or the file name converted to CamelCase. This
+  outer class will nest all classes and integer constants
+  generated from file-scope messages and enums.
+
+java_multiple_files={true,false} (no default)
+  This allows overriding the 'java_multiple_files' option
+  in all source files and their imported files from the
+  command line. The final value of this option for each
+  file is the value defined in this command line option, or
+  the value of the same option defined in the file if
+  present, or false. This specifies whether to generate
+  package-level classes for the file-scope messages in the
+  same Java package as the outer class (instead of nested
+  classes in the outer class). File-scope enum constants
+  are still generated as integer constants in the outer
+  class. This affects the fully qualified references in the
+  Java code. NOTE: because the command line option
+  overrides the value for all files and their imported
+  files, using this option inconsistently may result in
+  incorrect references to the imported messages and enum
+  constants.
+
+java_nano_generate_has={true,false} (default: false)
+  DEPRECATED. Use optional_field_style=accessors.
+
+  If true, generates a public boolean variable has<fieldname>
+  accompanying each optional or required field (not present for
+  repeated fields, groups or messages). It is set to false initially
+  and upon clear(). If parseFrom(...) reads the field from the wire,
+  it is set to true. This is a way for clients to inspect the "has"
+  value upon parse. If it is set to true, writeTo(...) will ALWAYS
+  output that field (even if field value is equal to its
+  default).
+
+  IMPORTANT: This option costs an extra 4 bytes per primitive field in
+  the message. Think carefully about whether you really need this. In
+  many cases reading the default works and determining whether the
+  field was received over the wire is irrelevant.
+
+optional_field_style={default,accessors,reftypes} (default: default)
+  Defines the style of the generated code for fields.
+
+  * default *
+
+  In the default style, optional fields translate into public mutable
+  Java fields, and the serialization process is as discussed in the
+  "IMPORTANT" section above. 
+
+  * accessors *
+
+  When set to 'accessors', each optional field is encapsulated behind
+  4 accessors, namely get<fieldname>(), set<fieldname>(), has<fieldname>()
+  and clear<fieldname>() methods, with the standard semantics. The hazzer's
+  return value determines whether a field is serialized, so this style is
+  useful when you need to serialize a field with the default value, or check
+  if a field has been explicitly set to its default value from the wire.
+
+  In the 'accessors' style, required and nested message fields are still
+  translated to one public mutable Java field each, repeated fields are still
+  translated to arrays. No accessors are generated for them.
+
+  IMPORTANT: When using the 'accessors' style, ProGuard should always
+  be enabled with optimization (don't use -dontoptimize) and allowing
+  access modification (use -allowaccessmodification). This removes the
+  unused accessors and maybe inline the rest at the call sites,
+  reducing the final code size.
+  TODO(maxtroy): find ProGuard config that would work the best.
+
+  * reftypes *
+
+  When set to 'reftypes', each proto field is generated as a public Java
+  field. For primitive types, these fields use the Java reference types
+  such as java.lang.Integer instead of primitive types such as int.
+
+  In the 'reftypes' style, fields are initialized to null (or empty
+  arrays for repeated fields), and their default values are not available.
+  They are serialized over the wire based on equality to null.
+
+  The 'reftypes' mode has some additional cost due to autoboxing and usage
+  of reference types. In practice, many boxed types are cached, and so don't
+  result in object creation. However, references do take slightly more memory
+  than primitives.
+
+  The 'reftypes' mode is useful when you want to be able to serialize fields
+  with default values, or check if a field has been explicitly set to the
+  default over the wire without paying the extra method cost of the
+  'accessors' mode.
+
+  Note that if you attempt to write null to a required field in the reftypes
+  mode, serialization of the proto will cause a NullPointerException. This is
+  an intentional indicator that you must set required fields.
+
+  NOTE
+  optional_field_style=accessors or reftypes cannot be used together with
+  java_nano_generate_has=true. If you need the 'has' flag for any
+  required field (you have no reason to), you can only use
+  java_nano_generate_has=true.
+
+enum_style={c,java} (default: c)
+  Defines where to put the int constants generated from enum members.
+
+  * c *
+
+  Use C-style, so the enum constants are available at the scope where
+  the enum is defined. A file-scope enum's members are referenced like
+  'FileOuterClass.ENUM_VALUE'; a message-scope enum's members are
+  referenced as 'Message.ENUM_VALUE'. The enum name is unavailable.
+  This complies with the Micro code generator's behavior.
+
+  * java *
+
+  Use Java-style, so the enum constants are available under the enum
+  name and referenced like 'EnumName.ENUM_VALUE' (they are still int
+  constants). The enum name becomes the name of a public interface, at
+  the scope where the enum is defined. If the enum is file-scope and
+  the java_multiple_files option is on, the interface will be defined
+  in its own file. To reduce code size, this interface should not be
+  implemented and ProGuard shrinking should be used, so after the Java
+  compiler inlines all referenced enum constants into the call sites,
+  the interface remains unused and can be removed by ProGuard.
+
+ignore_services={true,false} (default: false)
+  Skips services definitions.
+
+  Nano doesn't support services. By default, if a service is defined
+  it will generate a compilation error. If this flag is set to true,
+  services will be silently ignored, instead.
+
+parcelable_messages={true,false} (default: false)
+  Android-specific option to generate Parcelable messages.
+
+
+To use nano protobufs within the Android repo:
+
+- Set 'LOCAL_PROTOC_OPTIMIZE_TYPE := nano' in your local .mk file.
+  When building a Java library or an app (package) target, the build
+  system will add the Java nano runtime library to the
+  LOCAL_STATIC_JAVA_LIBRARIES variable, so you don't need to.
+- Set 'LOCAL_PROTO_JAVA_OUTPUT_PARAMS := ...' in your local .mk file
+  for any command-line options you need. Use commas to join multiple
+  options. In the nano flavor only, whitespace surrounding the option
+  names and values are ignored, so you can use backslash-newline or
+  '+=' to structure your make files nicely.
+- The options will be applied to *all* proto files in LOCAL_SRC_FILES
+  when you build a Java library or package. In case different options
+  are needed for different proto files, build separate Java libraries
+  and reference them in your main target. Note: you should make sure
+  that, for each separate target, all proto files imported from any
+  proto file in LOCAL_SRC_FILES are included in LOCAL_SRC_FILES. This
+  is because the generator has to assume that the imported files are
+  built using the same options, and will generate code that reference
+  the fields and enums from the imported files using the same code
+  style.
+- Hint: 'include $(CLEAR_VARS)' resets all LOCAL_ variables, including
+  the two above.
+
+To use nano protobufs outside of Android repo:
+
+- Link with the generated jar file
+  <protobuf-root>java/target/protobuf-java-2.3.0-nano.jar.
+- Invoke with --javanano_out, e.g.:
+
+./protoc '--javanano_out=\
+    java_package=src/proto/simple-data.proto|my_package,\
+    java_outer_classname=src/proto/simple-data.proto|OuterName\
+  :.' src/proto/simple-data.proto
+
+Contributing to nano:
+
+Please add/edit tests in NanoTest.java.
+
+Please run the following steps to test:
+
+- cd external/protobuf
+- ./configure
+- Run "make -j12 check" and verify all tests pass.
+- cd java
+- Run "mvn test" and verify all tests pass.
+- cd ../../..
+- . build/envsetup.sh
+- lunch 1
+- "make -j12 aprotoc libprotobuf-java-2.3.0-nano aprotoc-test-nano-params NanoAndroidTest" and
+  check for build errors.
+- Plug in an Android device or start an emulator.
+- adb install -r out/target/product/generic/data/app/NanoAndroidTest.apk
+- Run:
+  "adb shell am instrument -w com.google.protobuf.nano.test/android.test.InstrumentationTestRunner"
+  and verify all tests pass.
+- repo sync -c -j256
+- "make -j12" and check for build errors
+
+Usage
+=====
+
+The complete documentation for Protocol Buffers is available via the
+web at:
+
+  http://code.google.com/apis/protocolbuffers://developers.google.com/protocol-buffers/
diff --git a/javanano/pom.xml b/javanano/pom.xml
new file mode 100644
index 00000000..3d98a5e0
--- /dev/null
+++ b/javanano/pom.xml
@@ -0,0 +1,164 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.google</groupId>
+    <artifactId>google</artifactId>
+    <version>1</version>
+  </parent>
+  <groupId>com.google.protobuf.nano</groupId>
+  <artifactId>protobuf-javanano</artifactId>
+  <version>2.6.2-pre</version>
+  <packaging>bundle</packaging>
+  <name>Protocol Buffer JavaNano API</name>
+  <description>
+    Protocol Buffers are a way of encoding structured data in an efficient yet
+    extensible format.
+  </description>
+  <inceptionYear>2008</inceptionYear>
+  <url>https://developers.google.com/protocol-buffers/</url>
+  <licenses>
+    <license>
+      <name>New BSD license</name>
+      <url>http://www.opensource.org/licenses/bsd-license.php</url>
+      <distribution>repo</distribution>
+    </license>
+  </licenses>
+  <scm>
+    <url>https://github.com/google/protobuf</url>
+    <connection>
+      scm:git:https://github.com/google/protobuf.git
+    </connection>
+  </scm>
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.4</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.easymock</groupId>
+      <artifactId>easymock</artifactId>
+      <version>2.2</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.easymock</groupId>
+      <artifactId>easymockclassextension</artifactId>
+      <version>2.2.1</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <configuration>
+          <source>1.5</source>
+          <target>1.5</target>
+        </configuration>
+      </plugin>
+      <plugin>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <configuration>
+          <includes>
+            <include>**/*Test.java</include>
+          </includes>
+        </configuration>
+      </plugin>
+      <plugin>
+        <artifactId>maven-antrun-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>generate-test-sources</id>
+            <phase>generate-test-sources</phase>
+            <configuration>
+              <tasks>
+                <mkdir dir="target/generated-test-sources" />
+                <exec executable="../src/protoc">
+                  <arg value="--javanano_out=generate_equals=true:target/generated-test-sources" />
+                  <arg value="--proto_path=src/test/java/com" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_simple_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_stringutf8_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_recursive_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_import_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_single_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_multiple_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_multiple_nameclash_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_enum_class_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_repeated_merge_nano.proto" />
+                </exec>
+                <exec executable="../src/protoc">
+                  <arg value="--javanano_out=store_unknown_fields=true,generate_equals=true:target/generated-test-sources" />
+                  <arg value="--proto_path=src/test/java/com" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_extension_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_extension_singular_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_extension_repeated_nano.proto" />
+                </exec>
+                <exec executable="../src/protoc">
+                  <arg value="--javanano_out=store_unknown_fields=true:target/generated-test-sources" />
+                  <arg value="--proto_path=src/test/java/com" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_extension_packed_nano.proto" />
+                </exec>
+                <exec executable="../src/protoc">
+                  <arg value="--javanano_out=java_nano_generate_has=true,generate_equals=true:target/generated-test-sources" />
+                  <arg value="--proto_path=src/test/java/com" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_has_nano.proto" />
+                </exec>
+                <exec executable="../src/protoc">
+                  <arg value="--javanano_out=optional_field_style=accessors,generate_equals=true:target/generated-test-sources" />
+                  <arg value="--proto_path=src/test/java/com" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_accessors_nano.proto" />
+                </exec>
+                <exec executable="../src/protoc">
+                  <arg value="--javanano_out=enum_style=java:target/generated-test-sources" />
+                  <arg value="--proto_path=src/test/java/com" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_enum_class_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_enum_class_multiple_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_repeated_packables_nano.proto" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_enum_validity_nano.proto" />
+                </exec>
+                <exec executable="../src/protoc">
+                  <arg value="--javanano_out=
+                                  optional_field_style=accessors,
+                                  java_outer_classname=google/protobuf/nano/unittest_enum_validity_nano.proto|EnumValidityAccessors
+                                :target/generated-test-sources" />
+                  <arg value="--proto_path=src/test/java/com" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_enum_validity_nano.proto" />
+                </exec>
+                <exec executable="../src/protoc">
+                  <arg value="--javanano_out=optional_field_style=reftypes,generate_equals=true:target/generated-test-sources" />
+                  <arg value="--proto_path=src/test/java/com" />
+                  <arg value="src/test/java/com/google/protobuf/nano/unittest_reference_types_nano.proto" />
+                </exec>
+              </tasks>
+              <testSourceRoot>target/generated-test-sources</testSourceRoot>
+            </configuration>
+            <goals>
+              <goal>run</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.felix</groupId>
+        <artifactId>maven-bundle-plugin</artifactId>
+        <extensions>true</extensions>
+        <configuration>
+          <instructions>
+            <Bundle-DocURL>https://developers.google.com/protocol-buffers/</Bundle-DocURL>
+            <Bundle-SymbolicName>com.google.protobuf</Bundle-SymbolicName>
+            <Export-Package>com.google.protobuf;version=2.6.2-pre</Export-Package>
+          </instructions>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>
diff --git a/javanano/src/main/java/com/google/protobuf/nano/CodedInputByteBufferNano.java b/javanano/src/main/java/com/google/protobuf/nano/CodedInputByteBufferNano.java
new file mode 100644
index 00000000..c5fea5ae
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/CodedInputByteBufferNano.java
@@ -0,0 +1,641 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.io.IOException;
+
+/**
+ * Reads and decodes protocol message fields.
+ *
+ * This class contains two kinds of methods:  methods that read specific
+ * protocol message constructs and field types (e.g. {@link #readTag()} and
+ * {@link #readInt32()}) and methods that read low-level values (e.g.
+ * {@link #readRawVarint32()} and {@link #readRawBytes}).  If you are reading
+ * encoded protocol messages, you should use the former methods, but if you are
+ * reading some other format of your own design, use the latter.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+public final class CodedInputByteBufferNano {
+  /**
+   * Create a new CodedInputStream wrapping the given byte array.
+   */
+  public static CodedInputByteBufferNano newInstance(final byte[] buf) {
+    return newInstance(buf, 0, buf.length);
+  }
+
+  /**
+   * Create a new CodedInputStream wrapping the given byte array slice.
+   */
+  public static CodedInputByteBufferNano newInstance(final byte[] buf, final int off,
+                                             final int len) {
+    return new CodedInputByteBufferNano(buf, off, len);
+  }
+
+  // -----------------------------------------------------------------
+
+  /**
+   * Attempt to read a field tag, returning zero if we have reached EOF.
+   * Protocol message parsers use this to read tags, since a protocol message
+   * may legally end wherever a tag occurs, and zero is not a valid tag number.
+   */
+  public int readTag() throws IOException {
+    if (isAtEnd()) {
+      lastTag = 0;
+      return 0;
+    }
+
+    lastTag = readRawVarint32();
+    if (lastTag == 0) {
+      // If we actually read zero, that's not a valid tag.
+      throw InvalidProtocolBufferNanoException.invalidTag();
+    }
+    return lastTag;
+  }
+
+  /**
+   * Verifies that the last call to readTag() returned the given tag value.
+   * This is used to verify that a nested group ended with the correct
+   * end tag.
+   *
+   * @throws InvalidProtocolBufferNanoException {@code value} does not match the
+   *                                        last tag.
+   */
+  public void checkLastTagWas(final int value)
+                              throws InvalidProtocolBufferNanoException {
+    if (lastTag != value) {
+      throw InvalidProtocolBufferNanoException.invalidEndTag();
+    }
+  }
+
+  /**
+   * Reads and discards a single field, given its tag value.
+   *
+   * @return {@code false} if the tag is an endgroup tag, in which case
+   *         nothing is skipped.  Otherwise, returns {@code true}.
+   */
+  public boolean skipField(final int tag) throws IOException {
+    switch (WireFormatNano.getTagWireType(tag)) {
+      case WireFormatNano.WIRETYPE_VARINT:
+        readInt32();
+        return true;
+      case WireFormatNano.WIRETYPE_FIXED64:
+        readRawLittleEndian64();
+        return true;
+      case WireFormatNano.WIRETYPE_LENGTH_DELIMITED:
+        skipRawBytes(readRawVarint32());
+        return true;
+      case WireFormatNano.WIRETYPE_START_GROUP:
+        skipMessage();
+        checkLastTagWas(
+          WireFormatNano.makeTag(WireFormatNano.getTagFieldNumber(tag),
+                             WireFormatNano.WIRETYPE_END_GROUP));
+        return true;
+      case WireFormatNano.WIRETYPE_END_GROUP:
+        return false;
+      case WireFormatNano.WIRETYPE_FIXED32:
+        readRawLittleEndian32();
+        return true;
+      default:
+        throw InvalidProtocolBufferNanoException.invalidWireType();
+    }
+  }
+
+  /**
+   * Reads and discards an entire message.  This will read either until EOF
+   * or until an endgroup tag, whichever comes first.
+   */
+  public void skipMessage() throws IOException {
+    while (true) {
+      final int tag = readTag();
+      if (tag == 0 || !skipField(tag)) {
+        return;
+      }
+    }
+  }
+
+  // -----------------------------------------------------------------
+
+  /** Read a {@code double} field value from the stream. */
+  public double readDouble() throws IOException {
+    return Double.longBitsToDouble(readRawLittleEndian64());
+  }
+
+  /** Read a {@code float} field value from the stream. */
+  public float readFloat() throws IOException {
+    return Float.intBitsToFloat(readRawLittleEndian32());
+  }
+
+  /** Read a {@code uint64} field value from the stream. */
+  public long readUInt64() throws IOException {
+    return readRawVarint64();
+  }
+
+  /** Read an {@code int64} field value from the stream. */
+  public long readInt64() throws IOException {
+    return readRawVarint64();
+  }
+
+  /** Read an {@code int32} field value from the stream. */
+  public int readInt32() throws IOException {
+    return readRawVarint32();
+  }
+
+  /** Read a {@code fixed64} field value from the stream. */
+  public long readFixed64() throws IOException {
+    return readRawLittleEndian64();
+  }
+
+  /** Read a {@code fixed32} field value from the stream. */
+  public int readFixed32() throws IOException {
+    return readRawLittleEndian32();
+  }
+
+  /** Read a {@code bool} field value from the stream. */
+  public boolean readBool() throws IOException {
+    return readRawVarint32() != 0;
+  }
+
+  /** Read a {@code string} field value from the stream. */
+  public String readString() throws IOException {
+    final int size = readRawVarint32();
+    if (size <= (bufferSize - bufferPos) && size > 0) {
+      // Fast path:  We already have the bytes in a contiguous buffer, so
+      //   just copy directly from it.
+      final String result = new String(buffer, bufferPos, size, "UTF-8");
+      bufferPos += size;
+      return result;
+    } else {
+      // Slow path:  Build a byte array first then copy it.
+      return new String(readRawBytes(size), "UTF-8");
+    }
+  }
+
+  /** Read a {@code group} field value from the stream. */
+  public void readGroup(final MessageNano msg, final int fieldNumber)
+      throws IOException {
+    if (recursionDepth >= recursionLimit) {
+      throw InvalidProtocolBufferNanoException.recursionLimitExceeded();
+    }
+    ++recursionDepth;
+    msg.mergeFrom(this);
+    checkLastTagWas(
+      WireFormatNano.makeTag(fieldNumber, WireFormatNano.WIRETYPE_END_GROUP));
+    --recursionDepth;
+  }
+
+  public void readMessage(final MessageNano msg)
+      throws IOException {
+    final int length = readRawVarint32();
+    if (recursionDepth >= recursionLimit) {
+      throw InvalidProtocolBufferNanoException.recursionLimitExceeded();
+    }
+    final int oldLimit = pushLimit(length);
+    ++recursionDepth;
+    msg.mergeFrom(this);
+    checkLastTagWas(0);
+    --recursionDepth;
+    popLimit(oldLimit);
+  }
+
+  /** Read a {@code bytes} field value from the stream. */
+  public byte[] readBytes() throws IOException {
+    final int size = readRawVarint32();
+    if (size <= (bufferSize - bufferPos) && size > 0) {
+      // Fast path:  We already have the bytes in a contiguous buffer, so
+      //   just copy directly from it.
+      final byte[] result = new byte[size];
+      System.arraycopy(buffer, bufferPos, result, 0, size);
+      bufferPos += size;
+      return result;
+    } else {
+      // Slow path:  Build a byte array first then copy it.
+      return readRawBytes(size);
+    }
+  }
+
+  /** Read a {@code uint32} field value from the stream. */
+  public int readUInt32() throws IOException {
+    return readRawVarint32();
+  }
+
+  /**
+   * Read an enum field value from the stream.  Caller is responsible
+   * for converting the numeric value to an actual enum.
+   */
+  public int readEnum() throws IOException {
+    return readRawVarint32();
+  }
+
+  /** Read an {@code sfixed32} field value from the stream. */
+  public int readSFixed32() throws IOException {
+    return readRawLittleEndian32();
+  }
+
+  /** Read an {@code sfixed64} field value from the stream. */
+  public long readSFixed64() throws IOException {
+    return readRawLittleEndian64();
+  }
+
+  /** Read an {@code sint32} field value from the stream. */
+  public int readSInt32() throws IOException {
+    return decodeZigZag32(readRawVarint32());
+  }
+
+  /** Read an {@code sint64} field value from the stream. */
+  public long readSInt64() throws IOException {
+    return decodeZigZag64(readRawVarint64());
+  }
+
+  // =================================================================
+
+  /**
+   * Read a raw Varint from the stream.  If larger than 32 bits, discard the
+   * upper bits.
+   */
+  public int readRawVarint32() throws IOException {
+    byte tmp = readRawByte();
+    if (tmp >= 0) {
+      return tmp;
+    }
+    int result = tmp & 0x7f;
+    if ((tmp = readRawByte()) >= 0) {
+      result |= tmp << 7;
+    } else {
+      result |= (tmp & 0x7f) << 7;
+      if ((tmp = readRawByte()) >= 0) {
+        result |= tmp << 14;
+      } else {
+        result |= (tmp & 0x7f) << 14;
+        if ((tmp = readRawByte()) >= 0) {
+          result |= tmp << 21;
+        } else {
+          result |= (tmp & 0x7f) << 21;
+          result |= (tmp = readRawByte()) << 28;
+          if (tmp < 0) {
+            // Discard upper 32 bits.
+            for (int i = 0; i < 5; i++) {
+              if (readRawByte() >= 0) {
+                return result;
+              }
+            }
+            throw InvalidProtocolBufferNanoException.malformedVarint();
+          }
+        }
+      }
+    }
+    return result;
+  }
+
+  /** Read a raw Varint from the stream. */
+  public long readRawVarint64() throws IOException {
+    int shift = 0;
+    long result = 0;
+    while (shift < 64) {
+      final byte b = readRawByte();
+      result |= (long)(b & 0x7F) << shift;
+      if ((b & 0x80) == 0) {
+        return result;
+      }
+      shift += 7;
+    }
+    throw InvalidProtocolBufferNanoException.malformedVarint();
+  }
+
+  /** Read a 32-bit little-endian integer from the stream. */
+  public int readRawLittleEndian32() throws IOException {
+    final byte b1 = readRawByte();
+    final byte b2 = readRawByte();
+    final byte b3 = readRawByte();
+    final byte b4 = readRawByte();
+    return ((b1 & 0xff)      ) |
+           ((b2 & 0xff) <<  8) |
+           ((b3 & 0xff) << 16) |
+           ((b4 & 0xff) << 24);
+  }
+
+  /** Read a 64-bit little-endian integer from the stream. */
+  public long readRawLittleEndian64() throws IOException {
+    final byte b1 = readRawByte();
+    final byte b2 = readRawByte();
+    final byte b3 = readRawByte();
+    final byte b4 = readRawByte();
+    final byte b5 = readRawByte();
+    final byte b6 = readRawByte();
+    final byte b7 = readRawByte();
+    final byte b8 = readRawByte();
+    return (((long)b1 & 0xff)      ) |
+           (((long)b2 & 0xff) <<  8) |
+           (((long)b3 & 0xff) << 16) |
+           (((long)b4 & 0xff) << 24) |
+           (((long)b5 & 0xff) << 32) |
+           (((long)b6 & 0xff) << 40) |
+           (((long)b7 & 0xff) << 48) |
+           (((long)b8 & 0xff) << 56);
+  }
+
+  /**
+   * Decode a ZigZag-encoded 32-bit value.  ZigZag encodes signed integers
+   * into values that can be efficiently encoded with varint.  (Otherwise,
+   * negative values must be sign-extended to 64 bits to be varint encoded,
+   * thus always taking 10 bytes on the wire.)
+   *
+   * @param n An unsigned 32-bit integer, stored in a signed int because
+   *          Java has no explicit unsigned support.
+   * @return A signed 32-bit integer.
+   */
+  public static int decodeZigZag32(final int n) {
+    return (n >>> 1) ^ -(n & 1);
+  }
+
+  /**
+   * Decode a ZigZag-encoded 64-bit value.  ZigZag encodes signed integers
+   * into values that can be efficiently encoded with varint.  (Otherwise,
+   * negative values must be sign-extended to 64 bits to be varint encoded,
+   * thus always taking 10 bytes on the wire.)
+   *
+   * @param n An unsigned 64-bit integer, stored in a signed int because
+   *          Java has no explicit unsigned support.
+   * @return A signed 64-bit integer.
+   */
+  public static long decodeZigZag64(final long n) {
+    return (n >>> 1) ^ -(n & 1);
+  }
+
+  // -----------------------------------------------------------------
+
+  private final byte[] buffer;
+  private int bufferStart;
+  private int bufferSize;
+  private int bufferSizeAfterLimit;
+  private int bufferPos;
+  private int lastTag;
+
+  /** The absolute position of the end of the current message. */
+  private int currentLimit = Integer.MAX_VALUE;
+
+  /** See setRecursionLimit() */
+  private int recursionDepth;
+  private int recursionLimit = DEFAULT_RECURSION_LIMIT;
+
+  /** See setSizeLimit() */
+  private int sizeLimit = DEFAULT_SIZE_LIMIT;
+
+  private static final int DEFAULT_RECURSION_LIMIT = 64;
+  private static final int DEFAULT_SIZE_LIMIT = 64 << 20;  // 64MB
+
+  private CodedInputByteBufferNano(final byte[] buffer, final int off, final int len) {
+    this.buffer = buffer;
+    bufferStart = off;
+    bufferSize = off + len;
+    bufferPos = off;
+  }
+
+  /**
+   * Set the maximum message recursion depth.  In order to prevent malicious
+   * messages from causing stack overflows, {@code CodedInputStream} limits
+   * how deeply messages may be nested.  The default limit is 64.
+   *
+   * @return the old limit.
+   */
+  public int setRecursionLimit(final int limit) {
+    if (limit < 0) {
+      throw new IllegalArgumentException(
+        "Recursion limit cannot be negative: " + limit);
+    }
+    final int oldLimit = recursionLimit;
+    recursionLimit = limit;
+    return oldLimit;
+  }
+
+  /**
+   * Set the maximum message size.  In order to prevent malicious
+   * messages from exhausting memory or causing integer overflows,
+   * {@code CodedInputStream} limits how large a message may be.
+   * The default limit is 64MB.  You should set this limit as small
+   * as you can without harming your app's functionality.  Note that
+   * size limits only apply when reading from an {@code InputStream}, not
+   * when constructed around a raw byte array.
+   * <p>
+   * If you want to read several messages from a single CodedInputStream, you
+   * could call {@link #resetSizeCounter()} after each one to avoid hitting the
+   * size limit.
+   *
+   * @return the old limit.
+   */
+  public int setSizeLimit(final int limit) {
+    if (limit < 0) {
+      throw new IllegalArgumentException(
+        "Size limit cannot be negative: " + limit);
+    }
+    final int oldLimit = sizeLimit;
+    sizeLimit = limit;
+    return oldLimit;
+  }
+
+  /**
+   * Resets the current size counter to zero (see {@link #setSizeLimit(int)}).
+   */
+  public void resetSizeCounter() {
+  }
+
+  /**
+   * Sets {@code currentLimit} to (current position) + {@code byteLimit}.  This
+   * is called when descending into a length-delimited embedded message.
+   *
+   * @return the old limit.
+   */
+  public int pushLimit(int byteLimit) throws InvalidProtocolBufferNanoException {
+    if (byteLimit < 0) {
+      throw InvalidProtocolBufferNanoException.negativeSize();
+    }
+    byteLimit += bufferPos;
+    final int oldLimit = currentLimit;
+    if (byteLimit > oldLimit) {
+      throw InvalidProtocolBufferNanoException.truncatedMessage();
+    }
+    currentLimit = byteLimit;
+
+    recomputeBufferSizeAfterLimit();
+
+    return oldLimit;
+  }
+
+  private void recomputeBufferSizeAfterLimit() {
+    bufferSize += bufferSizeAfterLimit;
+    final int bufferEnd = bufferSize;
+    if (bufferEnd > currentLimit) {
+      // Limit is in current buffer.
+      bufferSizeAfterLimit = bufferEnd - currentLimit;
+      bufferSize -= bufferSizeAfterLimit;
+    } else {
+      bufferSizeAfterLimit = 0;
+    }
+  }
+
+  /**
+   * Discards the current limit, returning to the previous limit.
+   *
+   * @param oldLimit The old limit, as returned by {@code pushLimit}.
+   */
+  public void popLimit(final int oldLimit) {
+    currentLimit = oldLimit;
+    recomputeBufferSizeAfterLimit();
+  }
+
+  /**
+   * Returns the number of bytes to be read before the current limit.
+   * If no limit is set, returns -1.
+   */
+  public int getBytesUntilLimit() {
+    if (currentLimit == Integer.MAX_VALUE) {
+      return -1;
+    }
+
+    final int currentAbsolutePosition = bufferPos;
+    return currentLimit - currentAbsolutePosition;
+  }
+
+  /**
+   * Returns true if the stream has reached the end of the input.  This is the
+   * case if either the end of the underlying input source has been reached or
+   * if the stream has reached a limit created using {@link #pushLimit(int)}.
+   */
+  public boolean isAtEnd() {
+    return bufferPos == bufferSize;
+  }
+
+  /**
+   * Get current position in buffer relative to beginning offset.
+   */
+  public int getPosition() {
+    return bufferPos - bufferStart;
+  }
+
+  /**
+   * Retrieves a subset of data in the buffer. The returned array is not backed by the original
+   * buffer array.
+   *
+   * @param offset the position (relative to the buffer start position) to start at.
+   * @param length the number of bytes to retrieve.
+   */
+  public byte[] getData(int offset, int length) {
+    if (length == 0) {
+      return WireFormatNano.EMPTY_BYTES;
+    }
+    byte[] copy = new byte[length];
+    int start = bufferStart + offset;
+    System.arraycopy(buffer, start, copy, 0, length);
+    return copy;
+  }
+
+  /**
+   * Rewind to previous position. Cannot go forward.
+   */
+  public void rewindToPosition(int position) {
+    if (position > bufferPos - bufferStart) {
+      throw new IllegalArgumentException(
+              "Position " + position + " is beyond current " + (bufferPos - bufferStart));
+    }
+    if (position < 0) {
+      throw new IllegalArgumentException("Bad position " + position);
+    }
+    bufferPos = bufferStart + position;
+  }
+
+  /**
+   * Read one byte from the input.
+   *
+   * @throws InvalidProtocolBufferNanoException The end of the stream or the current
+   *                                        limit was reached.
+   */
+  public byte readRawByte() throws IOException {
+    if (bufferPos == bufferSize) {
+      throw InvalidProtocolBufferNanoException.truncatedMessage();
+    }
+    return buffer[bufferPos++];
+  }
+
+  /**
+   * Read a fixed size of bytes from the input.
+   *
+   * @throws InvalidProtocolBufferNanoException The end of the stream or the current
+   *                                        limit was reached.
+   */
+  public byte[] readRawBytes(final int size) throws IOException {
+    if (size < 0) {
+      throw InvalidProtocolBufferNanoException.negativeSize();
+    }
+
+    if (bufferPos + size > currentLimit) {
+      // Read to the end of the stream anyway.
+      skipRawBytes(currentLimit - bufferPos);
+      // Then fail.
+      throw InvalidProtocolBufferNanoException.truncatedMessage();
+    }
+
+    if (size <= bufferSize - bufferPos) {
+      // We have all the bytes we need already.
+      final byte[] bytes = new byte[size];
+      System.arraycopy(buffer, bufferPos, bytes, 0, size);
+      bufferPos += size;
+      return bytes;
+    } else {
+      throw InvalidProtocolBufferNanoException.truncatedMessage();
+    }
+  }
+
+  /**
+   * Reads and discards {@code size} bytes.
+   *
+   * @throws InvalidProtocolBufferNanoException The end of the stream or the current
+   *                                        limit was reached.
+   */
+  public void skipRawBytes(final int size) throws IOException {
+    if (size < 0) {
+      throw InvalidProtocolBufferNanoException.negativeSize();
+    }
+
+    if (bufferPos + size > currentLimit) {
+      // Read to the end of the stream anyway.
+      skipRawBytes(currentLimit - bufferPos);
+      // Then fail.
+      throw InvalidProtocolBufferNanoException.truncatedMessage();
+    }
+
+    if (size <= bufferSize - bufferPos) {
+      // We have all the bytes we need already.
+      bufferPos += size;
+    } else {
+      throw InvalidProtocolBufferNanoException.truncatedMessage();
+    }
+  }
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/CodedOutputByteBufferNano.java b/javanano/src/main/java/com/google/protobuf/nano/CodedOutputByteBufferNano.java
new file mode 100644
index 00000000..88df38d7
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/CodedOutputByteBufferNano.java
@@ -0,0 +1,879 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+
+/**
+ * Encodes and writes protocol message fields.
+ *
+ * <p>This class contains two kinds of methods:  methods that write specific
+ * protocol message constructs and field types (e.g. {@link #writeTag} and
+ * {@link #writeInt32}) and methods that write low-level values (e.g.
+ * {@link #writeRawVarint32} and {@link #writeRawBytes}).  If you are
+ * writing encoded protocol messages, you should use the former methods, but if
+ * you are writing some other format of your own design, use the latter.
+ *
+ * <p>This class is totally unsynchronized.
+ *
+ * @author kneton@google.com Kenton Varda
+ */
+public final class CodedOutputByteBufferNano {
+  private final byte[] buffer;
+  private final int limit;
+  private int position;
+
+  private CodedOutputByteBufferNano(final byte[] buffer, final int offset,
+                            final int length) {
+    this.buffer = buffer;
+    position = offset;
+    limit = offset + length;
+  }
+
+  /**
+   * Create a new {@code CodedOutputStream} that writes directly to the given
+   * byte array.  If more bytes are written than fit in the array,
+   * {@link OutOfSpaceException} will be thrown.  Writing directly to a flat
+   * array is faster than writing to an {@code OutputStream}.
+   */
+  public static CodedOutputByteBufferNano newInstance(final byte[] flatArray) {
+    return newInstance(flatArray, 0, flatArray.length);
+  }
+
+  /**
+   * Create a new {@code CodedOutputStream} that writes directly to the given
+   * byte array slice.  If more bytes are written than fit in the slice,
+   * {@link OutOfSpaceException} will be thrown.  Writing directly to a flat
+   * array is faster than writing to an {@code OutputStream}.
+   */
+  public static CodedOutputByteBufferNano newInstance(final byte[] flatArray,
+                                              final int offset,
+                                              final int length) {
+    return new CodedOutputByteBufferNano(flatArray, offset, length);
+  }
+
+  // -----------------------------------------------------------------
+
+  /** Write a {@code double} field, including tag, to the stream. */
+  public void writeDouble(final int fieldNumber, final double value)
+                          throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_FIXED64);
+    writeDoubleNoTag(value);
+  }
+
+  /** Write a {@code float} field, including tag, to the stream. */
+  public void writeFloat(final int fieldNumber, final float value)
+                         throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_FIXED32);
+    writeFloatNoTag(value);
+  }
+
+  /** Write a {@code uint64} field, including tag, to the stream. */
+  public void writeUInt64(final int fieldNumber, final long value)
+                          throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_VARINT);
+    writeUInt64NoTag(value);
+  }
+
+  /** Write an {@code int64} field, including tag, to the stream. */
+  public void writeInt64(final int fieldNumber, final long value)
+                         throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_VARINT);
+    writeInt64NoTag(value);
+  }
+
+  /** Write an {@code int32} field, including tag, to the stream. */
+  public void writeInt32(final int fieldNumber, final int value)
+                         throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_VARINT);
+    writeInt32NoTag(value);
+  }
+
+  /** Write a {@code fixed64} field, including tag, to the stream. */
+  public void writeFixed64(final int fieldNumber, final long value)
+                           throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_FIXED64);
+    writeFixed64NoTag(value);
+  }
+
+  /** Write a {@code fixed32} field, including tag, to the stream. */
+  public void writeFixed32(final int fieldNumber, final int value)
+                           throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_FIXED32);
+    writeFixed32NoTag(value);
+  }
+
+  /** Write a {@code bool} field, including tag, to the stream. */
+  public void writeBool(final int fieldNumber, final boolean value)
+                        throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_VARINT);
+    writeBoolNoTag(value);
+  }
+
+  /** Write a {@code string} field, including tag, to the stream. */
+  public void writeString(final int fieldNumber, final String value)
+                          throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_LENGTH_DELIMITED);
+    writeStringNoTag(value);
+  }
+
+  /** Write a {@code group} field, including tag, to the stream. */
+  public void writeGroup(final int fieldNumber, final MessageNano value)
+                         throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_START_GROUP);
+    writeGroupNoTag(value);
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_END_GROUP);
+  }
+
+  /** Write an embedded message field, including tag, to the stream. */
+  public void writeMessage(final int fieldNumber, final MessageNano value)
+                           throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_LENGTH_DELIMITED);
+    writeMessageNoTag(value);
+  }
+
+  /** Write a {@code bytes} field, including tag, to the stream. */
+  public void writeBytes(final int fieldNumber, final byte[] value)
+                         throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_LENGTH_DELIMITED);
+    writeBytesNoTag(value);
+  }
+
+  /** Write a {@code uint32} field, including tag, to the stream. */
+  public void writeUInt32(final int fieldNumber, final int value)
+                          throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_VARINT);
+    writeUInt32NoTag(value);
+  }
+
+  /**
+   * Write an enum field, including tag, to the stream.  Caller is responsible
+   * for converting the enum value to its numeric value.
+   */
+  public void writeEnum(final int fieldNumber, final int value)
+                        throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_VARINT);
+    writeEnumNoTag(value);
+  }
+
+  /** Write an {@code sfixed32} field, including tag, to the stream. */
+  public void writeSFixed32(final int fieldNumber, final int value)
+                            throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_FIXED32);
+    writeSFixed32NoTag(value);
+  }
+
+  /** Write an {@code sfixed64} field, including tag, to the stream. */
+  public void writeSFixed64(final int fieldNumber, final long value)
+                            throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_FIXED64);
+    writeSFixed64NoTag(value);
+  }
+
+  /** Write an {@code sint32} field, including tag, to the stream. */
+  public void writeSInt32(final int fieldNumber, final int value)
+                          throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_VARINT);
+    writeSInt32NoTag(value);
+  }
+
+  /** Write an {@code sint64} field, including tag, to the stream. */
+  public void writeSInt64(final int fieldNumber, final long value)
+                          throws IOException {
+    writeTag(fieldNumber, WireFormatNano.WIRETYPE_VARINT);
+    writeSInt64NoTag(value);
+  }
+
+  /**
+   * Write a MessageSet extension field to the stream.  For historical reasons,
+   * the wire format differs from normal fields.
+   */
+//  public void writeMessageSetExtension(final int fieldNumber,
+//                                       final MessageMicro value)
+//                                       throws IOException {
+//    writeTag(WireFormatMicro.MESSAGE_SET_ITEM, WireFormatMicro.WIRETYPE_START_GROUP);
+//    writeUInt32(WireFormatMicro.MESSAGE_SET_TYPE_ID, fieldNumber);
+//    writeMessage(WireFormatMicro.MESSAGE_SET_MESSAGE, value);
+//    writeTag(WireFormatMicro.MESSAGE_SET_ITEM, WireFormatMicro.WIRETYPE_END_GROUP);
+//  }
+
+  /**
+   * Write an unparsed MessageSet extension field to the stream.  For
+   * historical reasons, the wire format differs from normal fields.
+   */
+//  public void writeRawMessageSetExtension(final int fieldNumber,
+//                                          final ByteStringMicro value)
+//                                          throws IOException {
+//    writeTag(WireFormatMicro.MESSAGE_SET_ITEM, WireFormatMicro.WIRETYPE_START_GROUP);
+//    writeUInt32(WireFormatMicro.MESSAGE_SET_TYPE_ID, fieldNumber);
+//    writeBytes(WireFormatMicro.MESSAGE_SET_MESSAGE, value);
+//    writeTag(WireFormatMicro.MESSAGE_SET_ITEM, WireFormatMicro.WIRETYPE_END_GROUP);
+//  }
+
+  // -----------------------------------------------------------------
+
+  /** Write a {@code double} field to the stream. */
+  public void writeDoubleNoTag(final double value) throws IOException {
+    writeRawLittleEndian64(Double.doubleToLongBits(value));
+  }
+
+  /** Write a {@code float} field to the stream. */
+  public void writeFloatNoTag(final float value) throws IOException {
+    writeRawLittleEndian32(Float.floatToIntBits(value));
+  }
+
+  /** Write a {@code uint64} field to the stream. */
+  public void writeUInt64NoTag(final long value) throws IOException {
+    writeRawVarint64(value);
+  }
+
+  /** Write an {@code int64} field to the stream. */
+  public void writeInt64NoTag(final long value) throws IOException {
+    writeRawVarint64(value);
+  }
+
+  /** Write an {@code int32} field to the stream. */
+  public void writeInt32NoTag(final int value) throws IOException {
+    if (value >= 0) {
+      writeRawVarint32(value);
+    } else {
+      // Must sign-extend.
+      writeRawVarint64(value);
+    }
+  }
+
+  /** Write a {@code fixed64} field to the stream. */
+  public void writeFixed64NoTag(final long value) throws IOException {
+    writeRawLittleEndian64(value);
+  }
+
+  /** Write a {@code fixed32} field to the stream. */
+  public void writeFixed32NoTag(final int value) throws IOException {
+    writeRawLittleEndian32(value);
+  }
+
+  /** Write a {@code bool} field to the stream. */
+  public void writeBoolNoTag(final boolean value) throws IOException {
+    writeRawByte(value ? 1 : 0);
+  }
+
+  /** Write a {@code string} field to the stream. */
+  public void writeStringNoTag(final String value) throws IOException {
+    // Unfortunately there does not appear to be any way to tell Java to encode
+    // UTF-8 directly into our buffer, so we have to let it create its own byte
+    // array and then copy.
+    final byte[] bytes = value.getBytes("UTF-8");
+    writeRawVarint32(bytes.length);
+    writeRawBytes(bytes);
+  }
+
+  /** Write a {@code group} field to the stream. */
+  public void writeGroupNoTag(final MessageNano value) throws IOException {
+    value.writeTo(this);
+  }
+
+  /** Write an embedded message field to the stream. */
+  public void writeMessageNoTag(final MessageNano value) throws IOException {
+    writeRawVarint32(value.getCachedSize());
+    value.writeTo(this);
+  }
+
+  /** Write a {@code bytes} field to the stream. */
+  public void writeBytesNoTag(final byte[] value) throws IOException {
+    writeRawVarint32(value.length);
+    writeRawBytes(value);
+  }
+
+  /** Write a {@code uint32} field to the stream. */
+  public void writeUInt32NoTag(final int value) throws IOException {
+    writeRawVarint32(value);
+  }
+
+  /**
+   * Write an enum field to the stream.  Caller is responsible
+   * for converting the enum value to its numeric value.
+   */
+  public void writeEnumNoTag(final int value) throws IOException {
+    writeRawVarint32(value);
+  }
+
+  /** Write an {@code sfixed32} field to the stream. */
+  public void writeSFixed32NoTag(final int value) throws IOException {
+    writeRawLittleEndian32(value);
+  }
+
+  /** Write an {@code sfixed64} field to the stream. */
+  public void writeSFixed64NoTag(final long value) throws IOException {
+    writeRawLittleEndian64(value);
+  }
+
+  /** Write an {@code sint32} field to the stream. */
+  public void writeSInt32NoTag(final int value) throws IOException {
+    writeRawVarint32(encodeZigZag32(value));
+  }
+
+  /** Write an {@code sint64} field to the stream. */
+  public void writeSInt64NoTag(final long value) throws IOException {
+    writeRawVarint64(encodeZigZag64(value));
+  }
+
+  // =================================================================
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code double} field, including tag.
+   */
+  public static int computeDoubleSize(final int fieldNumber,
+                                      final double value) {
+    return computeTagSize(fieldNumber) + computeDoubleSizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code float} field, including tag.
+   */
+  public static int computeFloatSize(final int fieldNumber, final float value) {
+    return computeTagSize(fieldNumber) + computeFloatSizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code uint64} field, including tag.
+   */
+  public static int computeUInt64Size(final int fieldNumber, final long value) {
+    return computeTagSize(fieldNumber) + computeUInt64SizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code int64} field, including tag.
+   */
+  public static int computeInt64Size(final int fieldNumber, final long value) {
+    return computeTagSize(fieldNumber) + computeInt64SizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code int32} field, including tag.
+   */
+  public static int computeInt32Size(final int fieldNumber, final int value) {
+    return computeTagSize(fieldNumber) + computeInt32SizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code fixed64} field, including tag.
+   */
+  public static int computeFixed64Size(final int fieldNumber,
+                                       final long value) {
+    return computeTagSize(fieldNumber) + computeFixed64SizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code fixed32} field, including tag.
+   */
+  public static int computeFixed32Size(final int fieldNumber,
+                                       final int value) {
+    return computeTagSize(fieldNumber) + computeFixed32SizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code bool} field, including tag.
+   */
+  public static int computeBoolSize(final int fieldNumber,
+                                    final boolean value) {
+    return computeTagSize(fieldNumber) + computeBoolSizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code string} field, including tag.
+   */
+  public static int computeStringSize(final int fieldNumber,
+                                      final String value) {
+    return computeTagSize(fieldNumber) + computeStringSizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code group} field, including tag.
+   */
+  public static int computeGroupSize(final int fieldNumber,
+                                     final MessageNano value) {
+    return computeTagSize(fieldNumber) * 2 + computeGroupSizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * embedded message field, including tag.
+   */
+  public static int computeMessageSize(final int fieldNumber,
+                                       final MessageNano value) {
+    return computeTagSize(fieldNumber) + computeMessageSizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code bytes} field, including tag.
+   */
+  public static int computeBytesSize(final int fieldNumber,
+                                     final byte[] value) {
+    return computeTagSize(fieldNumber) + computeBytesSizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code uint32} field, including tag.
+   */
+  public static int computeUInt32Size(final int fieldNumber, final int value) {
+    return computeTagSize(fieldNumber) + computeUInt32SizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * enum field, including tag.  Caller is responsible for converting the
+   * enum value to its numeric value.
+   */
+  public static int computeEnumSize(final int fieldNumber, final int value) {
+    return computeTagSize(fieldNumber) + computeEnumSizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sfixed32} field, including tag.
+   */
+  public static int computeSFixed32Size(final int fieldNumber,
+                                        final int value) {
+    return computeTagSize(fieldNumber) + computeSFixed32SizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sfixed64} field, including tag.
+   */
+  public static int computeSFixed64Size(final int fieldNumber,
+                                        final long value) {
+    return computeTagSize(fieldNumber) + computeSFixed64SizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sint32} field, including tag.
+   */
+  public static int computeSInt32Size(final int fieldNumber, final int value) {
+    return computeTagSize(fieldNumber) + computeSInt32SizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sint64} field, including tag.
+   */
+  public static int computeSInt64Size(final int fieldNumber, final long value) {
+    return computeTagSize(fieldNumber) + computeSInt64SizeNoTag(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * MessageSet extension to the stream.  For historical reasons,
+   * the wire format differs from normal fields.
+   */
+//  public static int computeMessageSetExtensionSize(
+//      final int fieldNumber, final MessageMicro value) {
+//    return computeTagSize(WireFormatMicro.MESSAGE_SET_ITEM) * 2 +
+//           computeUInt32Size(WireFormatMicro.MESSAGE_SET_TYPE_ID, fieldNumber) +
+//           computeMessageSize(WireFormatMicro.MESSAGE_SET_MESSAGE, value);
+//  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * unparsed MessageSet extension field to the stream.  For
+   * historical reasons, the wire format differs from normal fields.
+   */
+//  public static int computeRawMessageSetExtensionSize(
+//      final int fieldNumber, final ByteStringMicro value) {
+//    return computeTagSize(WireFormatMicro.MESSAGE_SET_ITEM) * 2 +
+//           computeUInt32Size(WireFormatMicro.MESSAGE_SET_TYPE_ID, fieldNumber) +
+//           computeBytesSize(WireFormatMicro.MESSAGE_SET_MESSAGE, value);
+//  }
+
+  // -----------------------------------------------------------------
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code double} field, including tag.
+   */
+  public static int computeDoubleSizeNoTag(final double value) {
+    return LITTLE_ENDIAN_64_SIZE;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code float} field, including tag.
+   */
+  public static int computeFloatSizeNoTag(final float value) {
+    return LITTLE_ENDIAN_32_SIZE;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code uint64} field, including tag.
+   */
+  public static int computeUInt64SizeNoTag(final long value) {
+    return computeRawVarint64Size(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code int64} field, including tag.
+   */
+  public static int computeInt64SizeNoTag(final long value) {
+    return computeRawVarint64Size(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code int32} field, including tag.
+   */
+  public static int computeInt32SizeNoTag(final int value) {
+    if (value >= 0) {
+      return computeRawVarint32Size(value);
+    } else {
+      // Must sign-extend.
+      return 10;
+    }
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code fixed64} field.
+   */
+  public static int computeFixed64SizeNoTag(final long value) {
+    return LITTLE_ENDIAN_64_SIZE;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code fixed32} field.
+   */
+  public static int computeFixed32SizeNoTag(final int value) {
+    return LITTLE_ENDIAN_32_SIZE;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code bool} field.
+   */
+  public static int computeBoolSizeNoTag(final boolean value) {
+    return 1;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code string} field.
+   */
+  public static int computeStringSizeNoTag(final String value) {
+    try {
+      final byte[] bytes = value.getBytes("UTF-8");
+      return computeRawVarint32Size(bytes.length) +
+             bytes.length;
+    } catch (UnsupportedEncodingException e) {
+      throw new RuntimeException("UTF-8 not supported.");
+    }
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code group} field.
+   */
+  public static int computeGroupSizeNoTag(final MessageNano value) {
+    return value.getSerializedSize();
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an embedded
+   * message field.
+   */
+  public static int computeMessageSizeNoTag(final MessageNano value) {
+    final int size = value.getSerializedSize();
+    return computeRawVarint32Size(size) + size;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code bytes} field.
+   */
+  public static int computeBytesSizeNoTag(final byte[] value) {
+    return computeRawVarint32Size(value.length) + value.length;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a
+   * {@code uint32} field.
+   */
+  public static int computeUInt32SizeNoTag(final int value) {
+    return computeRawVarint32Size(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an enum field.
+   * Caller is responsible for converting the enum value to its numeric value.
+   */
+  public static int computeEnumSizeNoTag(final int value) {
+    return computeRawVarint32Size(value);
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sfixed32} field.
+   */
+  public static int computeSFixed32SizeNoTag(final int value) {
+    return LITTLE_ENDIAN_32_SIZE;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sfixed64} field.
+   */
+  public static int computeSFixed64SizeNoTag(final long value) {
+    return LITTLE_ENDIAN_64_SIZE;
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sint32} field.
+   */
+  public static int computeSInt32SizeNoTag(final int value) {
+    return computeRawVarint32Size(encodeZigZag32(value));
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode an
+   * {@code sint64} field.
+   */
+  public static int computeSInt64SizeNoTag(final long value) {
+    return computeRawVarint64Size(encodeZigZag64(value));
+  }
+
+  // =================================================================
+
+  /**
+   * If writing to a flat array, return the space left in the array.
+   * Otherwise, throws {@code UnsupportedOperationException}.
+   */
+  public int spaceLeft() {
+    return limit - position;
+  }
+
+  /**
+   * Verifies that {@link #spaceLeft()} returns zero.  It's common to create
+   * a byte array that is exactly big enough to hold a message, then write to
+   * it with a {@code CodedOutputStream}.  Calling {@code checkNoSpaceLeft()}
+   * after writing verifies that the message was actually as big as expected,
+   * which can help catch bugs.
+   */
+  public void checkNoSpaceLeft() {
+    if (spaceLeft() != 0) {
+      throw new IllegalStateException(
+        "Did not write as much data as expected.");
+    }
+  }
+
+  /**
+   * If you create a CodedOutputStream around a simple flat array, you must
+   * not attempt to write more bytes than the array has space.  Otherwise,
+   * this exception will be thrown.
+   */
+  public static class OutOfSpaceException extends IOException {
+    private static final long serialVersionUID = -6947486886997889499L;
+
+    OutOfSpaceException(int position, int limit) {
+      super("CodedOutputStream was writing to a flat byte array and ran " +
+            "out of space (pos " + position + " limit " + limit + ").");
+    }
+  }
+
+  /** Write a single byte. */
+  public void writeRawByte(final byte value) throws IOException {
+    if (position == limit) {
+      // We're writing to a single buffer.
+      throw new OutOfSpaceException(position, limit);
+    }
+
+    buffer[position++] = value;
+  }
+
+  /** Write a single byte, represented by an integer value. */
+  public void writeRawByte(final int value) throws IOException {
+    writeRawByte((byte) value);
+  }
+
+  /** Write an array of bytes. */
+  public void writeRawBytes(final byte[] value) throws IOException {
+    writeRawBytes(value, 0, value.length);
+  }
+
+  /** Write part of an array of bytes. */
+  public void writeRawBytes(final byte[] value, int offset, int length)
+                            throws IOException {
+    if (limit - position >= length) {
+      // We have room in the current buffer.
+      System.arraycopy(value, offset, buffer, position, length);
+      position += length;
+    } else {
+      // We're writing to a single buffer.
+      throw new OutOfSpaceException(position, limit);
+    }
+  }
+
+  /** Encode and write a tag. */
+  public void writeTag(final int fieldNumber, final int wireType)
+                       throws IOException {
+    writeRawVarint32(WireFormatNano.makeTag(fieldNumber, wireType));
+  }
+
+  /** Compute the number of bytes that would be needed to encode a tag. */
+  public static int computeTagSize(final int fieldNumber) {
+    return computeRawVarint32Size(WireFormatNano.makeTag(fieldNumber, 0));
+  }
+
+  /**
+   * Encode and write a varint.  {@code value} is treated as
+   * unsigned, so it won't be sign-extended if negative.
+   */
+  public void writeRawVarint32(int value) throws IOException {
+    while (true) {
+      if ((value & ~0x7F) == 0) {
+        writeRawByte(value);
+        return;
+      } else {
+        writeRawByte((value & 0x7F) | 0x80);
+        value >>>= 7;
+      }
+    }
+  }
+
+  /**
+   * Compute the number of bytes that would be needed to encode a varint.
+   * {@code value} is treated as unsigned, so it won't be sign-extended if
+   * negative.
+   */
+  public static int computeRawVarint32Size(final int value) {
+    if ((value & (0xffffffff <<  7)) == 0) return 1;
+    if ((value & (0xffffffff << 14)) == 0) return 2;
+    if ((value & (0xffffffff << 21)) == 0) return 3;
+    if ((value & (0xffffffff << 28)) == 0) return 4;
+    return 5;
+  }
+
+  /** Encode and write a varint. */
+  public void writeRawVarint64(long value) throws IOException {
+    while (true) {
+      if ((value & ~0x7FL) == 0) {
+        writeRawByte((int)value);
+        return;
+      } else {
+        writeRawByte(((int)value & 0x7F) | 0x80);
+        value >>>= 7;
+      }
+    }
+  }
+
+  /** Compute the number of bytes that would be needed to encode a varint. */
+  public static int computeRawVarint64Size(final long value) {
+    if ((value & (0xffffffffffffffffL <<  7)) == 0) return 1;
+    if ((value & (0xffffffffffffffffL << 14)) == 0) return 2;
+    if ((value & (0xffffffffffffffffL << 21)) == 0) return 3;
+    if ((value & (0xffffffffffffffffL << 28)) == 0) return 4;
+    if ((value & (0xffffffffffffffffL << 35)) == 0) return 5;
+    if ((value & (0xffffffffffffffffL << 42)) == 0) return 6;
+    if ((value & (0xffffffffffffffffL << 49)) == 0) return 7;
+    if ((value & (0xffffffffffffffffL << 56)) == 0) return 8;
+    if ((value & (0xffffffffffffffffL << 63)) == 0) return 9;
+    return 10;
+  }
+
+  /** Write a little-endian 32-bit integer. */
+  public void writeRawLittleEndian32(final int value) throws IOException {
+    writeRawByte((value      ) & 0xFF);
+    writeRawByte((value >>  8) & 0xFF);
+    writeRawByte((value >> 16) & 0xFF);
+    writeRawByte((value >> 24) & 0xFF);
+  }
+
+  public static final int LITTLE_ENDIAN_32_SIZE = 4;
+
+  /** Write a little-endian 64-bit integer. */
+  public void writeRawLittleEndian64(final long value) throws IOException {
+    writeRawByte((int)(value      ) & 0xFF);
+    writeRawByte((int)(value >>  8) & 0xFF);
+    writeRawByte((int)(value >> 16) & 0xFF);
+    writeRawByte((int)(value >> 24) & 0xFF);
+    writeRawByte((int)(value >> 32) & 0xFF);
+    writeRawByte((int)(value >> 40) & 0xFF);
+    writeRawByte((int)(value >> 48) & 0xFF);
+    writeRawByte((int)(value >> 56) & 0xFF);
+  }
+
+  public static final int LITTLE_ENDIAN_64_SIZE = 8;
+
+  /**
+   * Encode a ZigZag-encoded 32-bit value.  ZigZag encodes signed integers
+   * into values that can be efficiently encoded with varint.  (Otherwise,
+   * negative values must be sign-extended to 64 bits to be varint encoded,
+   * thus always taking 10 bytes on the wire.)
+   *
+   * @param n A signed 32-bit integer.
+   * @return An unsigned 32-bit integer, stored in a signed int because
+   *         Java has no explicit unsigned support.
+   */
+  public static int encodeZigZag32(final int n) {
+    // Note:  the right-shift must be arithmetic
+    return (n << 1) ^ (n >> 31);
+  }
+
+  /**
+   * Encode a ZigZag-encoded 64-bit value.  ZigZag encodes signed integers
+   * into values that can be efficiently encoded with varint.  (Otherwise,
+   * negative values must be sign-extended to 64 bits to be varint encoded,
+   * thus always taking 10 bytes on the wire.)
+   *
+   * @param n A signed 64-bit integer.
+   * @return An unsigned 64-bit integer, stored in a signed int because
+   *         Java has no explicit unsigned support.
+   */
+  public static long encodeZigZag64(final long n) {
+    // Note:  the right-shift must be arithmetic
+    return (n << 1) ^ (n >> 63);
+  }
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/ExtendableMessageNano.java b/javanano/src/main/java/com/google/protobuf/nano/ExtendableMessageNano.java
new file mode 100644
index 00000000..46cd86f3
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/ExtendableMessageNano.java
@@ -0,0 +1,187 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.io.IOException;
+
+/**
+ * Base class of those Protocol Buffer messages that need to store unknown fields,
+ * such as extensions.
+ */
+public abstract class ExtendableMessageNano<M extends ExtendableMessageNano<M>>
+        extends MessageNano {
+    /**
+     * A container for fields unknown to the message, including extensions. Extension fields can
+     * can be accessed through the {@link #getExtension} and {@link #setExtension} methods.
+     */
+    protected FieldArray unknownFieldData;
+
+    @Override
+    protected int computeSerializedSize() {
+        int size = 0;
+        if (unknownFieldData != null) {
+            for (int i = 0; i < unknownFieldData.size(); i++) {
+                FieldData field = unknownFieldData.dataAt(i);
+                size += field.computeSerializedSize();
+            }
+        }
+        return size;
+    }
+
+    @Override
+    public void writeTo(CodedOutputByteBufferNano output) throws IOException {
+        if (unknownFieldData == null) {
+            return;
+        }
+        for (int i = 0; i < unknownFieldData.size(); i++) {
+            FieldData field = unknownFieldData.dataAt(i);
+            field.writeTo(output);
+        }
+    }
+
+    /**
+     * Checks if there is a value stored for the specified extension in this
+     * message.
+     */
+    public final boolean hasExtension(Extension<M, ?> extension) {
+        if (unknownFieldData == null) {
+            return false;
+        }
+        FieldData field = unknownFieldData.get(WireFormatNano.getTagFieldNumber(extension.tag));
+        return field != null;
+    }
+
+    /**
+     * Gets the value stored in the specified extension of this message.
+     */
+    public final <T> T getExtension(Extension<M, T> extension) {
+        if (unknownFieldData == null) {
+            return null;
+        }
+        FieldData field = unknownFieldData.get(WireFormatNano.getTagFieldNumber(extension.tag));
+        return field == null ? null : field.getValue(extension);
+    }
+
+    /**
+     * Sets the value of the specified extension of this message.
+     */
+    public final <T> M setExtension(Extension<M, T> extension, T value) {
+        int fieldNumber = WireFormatNano.getTagFieldNumber(extension.tag);
+        if (value == null) {
+            if (unknownFieldData != null) {
+                unknownFieldData.remove(fieldNumber);
+                if (unknownFieldData.isEmpty()) {
+                    unknownFieldData = null;
+                }
+            }
+        } else {
+            FieldData field = null;
+            if (unknownFieldData == null) {
+                unknownFieldData = new FieldArray();
+            } else {
+                field = unknownFieldData.get(fieldNumber);
+            }
+            if (field == null) {
+                unknownFieldData.put(fieldNumber, new FieldData(extension, value));
+            } else {
+                field.setValue(extension, value);
+            }
+        }
+
+        @SuppressWarnings("unchecked") // Generated code should guarantee type safety
+        M typedThis = (M) this;
+        return typedThis;
+    }
+
+    /**
+     * Stores the binary data of an unknown field.
+     *
+     * <p>Generated messages will call this for unknown fields if the store_unknown_fields
+     * option is on.
+     *
+     * <p>Note that the tag might be a end-group tag (rather than the start of an unknown field) in
+     * which case we do not want to add an unknown field entry.
+     *
+     * @param input the input buffer.
+     * @param tag the tag of the field.
+
+     * @return {@literal true} unless the tag is an end-group tag.
+     */
+    protected final boolean storeUnknownField(CodedInputByteBufferNano input, int tag)
+            throws IOException {
+        int startPos = input.getPosition();
+        if (!input.skipField(tag)) {
+            return false;  // This wasn't an unknown field, it's an end-group tag.
+        }
+        int fieldNumber = WireFormatNano.getTagFieldNumber(tag);
+        int endPos = input.getPosition();
+        byte[] bytes = input.getData(startPos, endPos - startPos);
+        UnknownFieldData unknownField = new UnknownFieldData(tag, bytes);
+
+        FieldData field = null;
+        if (unknownFieldData == null) {
+            unknownFieldData = new FieldArray();
+        } else {
+            field = unknownFieldData.get(fieldNumber);
+        }
+        if (field == null) {
+            field = new FieldData();
+            unknownFieldData.put(fieldNumber, field);
+        }
+        field.addUnknownField(unknownField);
+        return true;
+    }
+
+    /**
+     * Returns whether the stored unknown field data in this message is equivalent to that in the
+     * other message.
+     *
+     * @param other the other message.
+     * @return whether the two sets of unknown field data are equal.
+     */
+    protected final boolean unknownFieldDataEquals(M other) {
+        if (unknownFieldData == null || unknownFieldData.isEmpty()) {
+            return other.unknownFieldData == null || other.unknownFieldData.isEmpty();
+        } else {
+            return unknownFieldData.equals(other.unknownFieldData);
+        }
+    }
+
+    /**
+     * Computes the hashcode representing the unknown field data stored in this message.
+     *
+     * @return the hashcode for the unknown field data.
+     */
+    protected final int unknownFieldDataHashCode() {
+        return (unknownFieldData == null || unknownFieldData.isEmpty()
+                ? 0 : unknownFieldData.hashCode());
+    }
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/Extension.java b/javanano/src/main/java/com/google/protobuf/nano/Extension.java
new file mode 100644
index 00000000..a851daf8
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/Extension.java
@@ -0,0 +1,722 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.io.IOException;
+import java.lang.reflect.Array;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Represents an extension.
+ *
+ * @author bduff@google.com (Brian Duff)
+ * @author maxtroy@google.com (Max Cai)
+ * @param <M> the type of the extendable message this extension is for.
+ * @param <T> the Java type of the extension; see {@link #clazz}.
+ */
+public class Extension<M extends ExtendableMessageNano<M>, T> {
+
+    /*
+     * Because we typically only define message-typed extensions, the Extension class hierarchy is
+     * designed as follows, to allow a big amount of code in this file to be removed by ProGuard:
+     *
+     *            Extension          // ready to use for message/group typed extensions
+     *                Δ
+     *                |
+     *       PrimitiveExtension      // for primitive/enum typed extensions
+     */
+
+    public static final int TYPE_DOUBLE   = 1;
+    public static final int TYPE_FLOAT    = 2;
+    public static final int TYPE_INT64    = 3;
+    public static final int TYPE_UINT64   = 4;
+    public static final int TYPE_INT32    = 5;
+    public static final int TYPE_FIXED64  = 6;
+    public static final int TYPE_FIXED32  = 7;
+    public static final int TYPE_BOOL     = 8;
+    public static final int TYPE_STRING   = 9;
+    public static final int TYPE_GROUP    = 10;
+    public static final int TYPE_MESSAGE  = 11;
+    public static final int TYPE_BYTES    = 12;
+    public static final int TYPE_UINT32   = 13;
+    public static final int TYPE_ENUM     = 14;
+    public static final int TYPE_SFIXED32 = 15;
+    public static final int TYPE_SFIXED64 = 16;
+    public static final int TYPE_SINT32   = 17;
+    public static final int TYPE_SINT64   = 18;
+
+    /**
+     * Creates an {@code Extension} of the given message type and tag number.
+     * Should be used by the generated code only.
+     *
+     * @param type {@link #TYPE_MESSAGE} or {@link #TYPE_GROUP}
+     */
+    public static <M extends ExtendableMessageNano<M>, T extends MessageNano>
+            Extension<M, T> createMessageTyped(int type, Class<T> clazz, int tag) {
+        return new Extension<M, T>(type, clazz, tag, false);
+    }
+
+    /**
+     * Creates a repeated {@code Extension} of the given message type and tag number.
+     * Should be used by the generated code only.
+     *
+     * @param type {@link #TYPE_MESSAGE} or {@link #TYPE_GROUP}
+     */
+    public static <M extends ExtendableMessageNano<M>, T extends MessageNano>
+            Extension<M, T[]> createRepeatedMessageTyped(int type, Class<T[]> clazz, int tag) {
+        return new Extension<M, T[]>(type, clazz, tag, true);
+    }
+
+    /**
+     * Creates an {@code Extension} of the given primitive type and tag number.
+     * Should be used by the generated code only.
+     *
+     * @param type one of {@code TYPE_*}, except {@link #TYPE_MESSAGE} and {@link #TYPE_GROUP}
+     * @param clazz the boxed Java type of this extension
+     */
+    public static <M extends ExtendableMessageNano<M>, T>
+            Extension<M, T> createPrimitiveTyped(int type, Class<T> clazz, int tag) {
+        return new PrimitiveExtension<M, T>(type, clazz, tag, false, 0, 0);
+    }
+
+    /**
+     * Creates a repeated {@code Extension} of the given primitive type and tag number.
+     * Should be used by the generated code only.
+     *
+     * @param type one of {@code TYPE_*}, except {@link #TYPE_MESSAGE} and {@link #TYPE_GROUP}
+     * @param clazz the Java array type of this extension, with an unboxed component type
+     */
+    public static <M extends ExtendableMessageNano<M>, T>
+            Extension<M, T> createRepeatedPrimitiveTyped(
+                    int type, Class<T> clazz, int tag, int nonPackedTag, int packedTag) {
+        return new PrimitiveExtension<M, T>(type, clazz, tag, true, nonPackedTag, packedTag);
+    }
+
+    /**
+     * Protocol Buffer type of this extension; one of the {@code TYPE_} constants.
+     */
+    protected final int type;
+
+    /**
+     * Java type of this extension. For a singular extension, this is the boxed Java type for the
+     * Protocol Buffer {@link #type}; for a repeated extension, this is an array type whose
+     * component type is the unboxed Java type for {@link #type}. For example, for a singular
+     * {@code int32}/{@link #TYPE_INT32} extension, this equals {@code Integer.class}; for a
+     * repeated {@code int32} extension, this equals {@code int[].class}.
+     */
+    protected final Class<T> clazz;
+
+    /**
+     * Tag number of this extension.
+     */
+    public final int tag;
+
+    /**
+     * Whether this extension is repeated.
+     */
+    protected final boolean repeated;
+
+    private Extension(int type, Class<T> clazz, int tag, boolean repeated) {
+        this.type = type;
+        this.clazz = clazz;
+        this.tag = tag;
+        this.repeated = repeated;
+    }
+
+    /**
+     * Returns the value of this extension stored in the given list of unknown fields, or
+     * {@code null} if no unknown fields matches this extension.
+     *
+     * @param unknownFields a list of {@link UnknownFieldData}. All of the elements must have a tag
+     *                      that matches this Extension's tag.
+     *
+     */
+    final T getValueFrom(List<UnknownFieldData> unknownFields) {
+        if (unknownFields == null) {
+            return null;
+        }
+        return repeated ? getRepeatedValueFrom(unknownFields) : getSingularValueFrom(unknownFields);
+    }
+
+    private T getRepeatedValueFrom(List<UnknownFieldData> unknownFields) {
+        // For repeated extensions, read all matching unknown fields in their original order.
+        List<Object> resultList = new ArrayList<Object>();
+        for (int i = 0; i < unknownFields.size(); i++) {
+            UnknownFieldData data = unknownFields.get(i);
+            if (data.bytes.length != 0) {
+                readDataInto(data, resultList);
+            }
+        }
+
+        int resultSize = resultList.size();
+        if (resultSize == 0) {
+            return null;
+        } else {
+            T result = clazz.cast(Array.newInstance(clazz.getComponentType(), resultSize));
+            for (int i = 0; i < resultSize; i++) {
+                Array.set(result, i, resultList.get(i));
+            }
+            return result;
+        }
+    }
+
+    private T getSingularValueFrom(List<UnknownFieldData> unknownFields) {
+        // For singular extensions, get the last piece of data stored under this extension.
+        if (unknownFields.isEmpty()) {
+            return null;
+        }
+        UnknownFieldData lastData = unknownFields.get(unknownFields.size() - 1);
+        return clazz.cast(readData(CodedInputByteBufferNano.newInstance(lastData.bytes)));
+    }
+
+    protected Object readData(CodedInputByteBufferNano input) {
+        // This implementation is for message/group extensions.
+        Class<?> messageType = repeated ? clazz.getComponentType() : clazz;
+        try {
+            switch (type) {
+                case TYPE_GROUP:
+                    MessageNano group = (MessageNano) messageType.newInstance();
+                    input.readGroup(group, WireFormatNano.getTagFieldNumber(tag));
+                    return group;
+                case TYPE_MESSAGE:
+                    MessageNano message = (MessageNano) messageType.newInstance();
+                    input.readMessage(message);
+                    return message;
+                default:
+                    throw new IllegalArgumentException("Unknown type " + type);
+            }
+        } catch (InstantiationException e) {
+            throw new IllegalArgumentException(
+                    "Error creating instance of class " + messageType, e);
+        } catch (IllegalAccessException e) {
+            throw new IllegalArgumentException(
+                    "Error creating instance of class " + messageType, e);
+        } catch (IOException e) {
+            throw new IllegalArgumentException("Error reading extension field", e);
+        }
+    }
+
+    protected void readDataInto(UnknownFieldData data, List<Object> resultList) {
+        // This implementation is for message/group extensions.
+        resultList.add(readData(CodedInputByteBufferNano.newInstance(data.bytes)));
+    }
+
+    void writeTo(Object value, CodedOutputByteBufferNano output) throws IOException {
+        if (repeated) {
+            writeRepeatedData(value, output);
+        } else {
+            writeSingularData(value, output);
+        }
+    }
+
+    protected void writeSingularData(Object value, CodedOutputByteBufferNano out) {
+        // This implementation is for message/group extensions.
+        try {
+            out.writeRawVarint32(tag);
+            switch (type) {
+                case TYPE_GROUP:
+                    MessageNano groupValue = (MessageNano) value;
+                    int fieldNumber = WireFormatNano.getTagFieldNumber(tag);
+                    out.writeGroupNoTag(groupValue);
+                    // The endgroup tag must be included in the data payload.
+                    out.writeTag(fieldNumber, WireFormatNano.WIRETYPE_END_GROUP);
+                    break;
+                case TYPE_MESSAGE:
+                    MessageNano messageValue = (MessageNano) value;
+                    out.writeMessageNoTag(messageValue);
+                    break;
+                default:
+                    throw new IllegalArgumentException("Unknown type " + type);
+            }
+        } catch (IOException e) {
+            // Should not happen
+            throw new IllegalStateException(e);
+        }
+    }
+
+    protected void writeRepeatedData(Object array, CodedOutputByteBufferNano output) {
+        // This implementation is for non-packed extensions.
+        int arrayLength = Array.getLength(array);
+        for (int i = 0; i < arrayLength; i++) {
+            Object element = Array.get(array, i);
+            if (element != null) {
+                writeSingularData(element, output);
+            }
+        }
+    }
+
+    int computeSerializedSize(Object value) {
+        if (repeated) {
+            return computeRepeatedSerializedSize(value);
+        } else {
+            return computeSingularSerializedSize(value);
+        }
+    }
+
+    protected int computeRepeatedSerializedSize(Object array) {
+        // This implementation is for non-packed extensions.
+        int size = 0;
+        int arrayLength = Array.getLength(array);
+        for (int i = 0; i < arrayLength; i++) {
+            Object element = Array.get(array, i);
+            if (element != null) {
+                size += computeSingularSerializedSize(Array.get(array, i));
+            }
+        }
+        return size;
+    }
+
+    protected int computeSingularSerializedSize(Object value) {
+        // This implementation is for message/group extensions.
+        int fieldNumber = WireFormatNano.getTagFieldNumber(tag);
+        switch (type) {
+            case TYPE_GROUP:
+                MessageNano groupValue = (MessageNano) value;
+                return CodedOutputByteBufferNano.computeGroupSize(fieldNumber, groupValue);
+            case TYPE_MESSAGE:
+                MessageNano messageValue = (MessageNano) value;
+                return CodedOutputByteBufferNano.computeMessageSize(fieldNumber, messageValue);
+            default:
+                throw new IllegalArgumentException("Unknown type " + type);
+        }
+    }
+
+    /**
+     * Represents an extension of a primitive (including enum) type. If there is no primitive
+     * extensions, this subclass will be removable by ProGuard.
+     */
+    private static class PrimitiveExtension<M extends ExtendableMessageNano<M>, T>
+            extends Extension<M, T> {
+
+        /**
+         * Tag of a piece of non-packed data from the wire compatible with this extension.
+         */
+        private final int nonPackedTag;
+
+        /**
+         * Tag of a piece of packed data from the wire compatible with this extension.
+         * 0 if the type of this extension is not packable.
+         */
+        private final int packedTag;
+
+        public PrimitiveExtension(int type, Class<T> clazz, int tag, boolean repeated,
+                int nonPackedTag, int packedTag) {
+            super(type, clazz, tag, repeated);
+            this.nonPackedTag = nonPackedTag;
+            this.packedTag = packedTag;
+        }
+
+        @Override
+        protected Object readData(CodedInputByteBufferNano input) {
+            try {
+                switch (type) {
+                    case TYPE_DOUBLE:
+                        return input.readDouble();
+                    case TYPE_FLOAT:
+                        return input.readFloat();
+                    case TYPE_INT64:
+                        return input.readInt64();
+                    case TYPE_UINT64:
+                        return input.readUInt64();
+                    case TYPE_INT32:
+                        return input.readInt32();
+                    case TYPE_FIXED64:
+                        return input.readFixed64();
+                    case TYPE_FIXED32:
+                        return input.readFixed32();
+                    case TYPE_BOOL:
+                        return input.readBool();
+                    case TYPE_STRING:
+                        return input.readString();
+                    case TYPE_BYTES:
+                        return input.readBytes();
+                    case TYPE_UINT32:
+                        return input.readUInt32();
+                    case TYPE_ENUM:
+                        return input.readEnum();
+                    case TYPE_SFIXED32:
+                        return input.readSFixed32();
+                    case TYPE_SFIXED64:
+                        return input.readSFixed64();
+                    case TYPE_SINT32:
+                        return input.readSInt32();
+                    case TYPE_SINT64:
+                        return input.readSInt64();
+                    default:
+                        throw new IllegalArgumentException("Unknown type " + type);
+                }
+            } catch (IOException e) {
+                throw new IllegalArgumentException("Error reading extension field", e);
+            }
+        }
+
+        @Override
+        protected void readDataInto(UnknownFieldData data, List<Object> resultList) {
+            // This implementation is for primitive typed extensions,
+            // which can read both packed and non-packed data.
+            if (data.tag == nonPackedTag) {
+                resultList.add(readData(CodedInputByteBufferNano.newInstance(data.bytes)));
+            } else {
+                CodedInputByteBufferNano buffer =
+                        CodedInputByteBufferNano.newInstance(data.bytes);
+                try {
+                    buffer.pushLimit(buffer.readRawVarint32()); // length limit
+                } catch (IOException e) {
+                    throw new IllegalArgumentException("Error reading extension field", e);
+                }
+                while (!buffer.isAtEnd()) {
+                    resultList.add(readData(buffer));
+                }
+            }
+        }
+
+        @Override
+        protected final void writeSingularData(Object value, CodedOutputByteBufferNano output) {
+            try {
+                output.writeRawVarint32(tag);
+                switch (type) {
+                    case TYPE_DOUBLE:
+                        Double doubleValue = (Double) value;
+                        output.writeDoubleNoTag(doubleValue);
+                        break;
+                    case TYPE_FLOAT:
+                        Float floatValue = (Float) value;
+                        output.writeFloatNoTag(floatValue);
+                        break;
+                    case TYPE_INT64:
+                        Long int64Value = (Long) value;
+                        output.writeInt64NoTag(int64Value);
+                        break;
+                    case TYPE_UINT64:
+                        Long uint64Value = (Long) value;
+                        output.writeUInt64NoTag(uint64Value);
+                        break;
+                    case TYPE_INT32:
+                        Integer int32Value = (Integer) value;
+                        output.writeInt32NoTag(int32Value);
+                        break;
+                    case TYPE_FIXED64:
+                        Long fixed64Value = (Long) value;
+                        output.writeFixed64NoTag(fixed64Value);
+                        break;
+                    case TYPE_FIXED32:
+                        Integer fixed32Value = (Integer) value;
+                        output.writeFixed32NoTag(fixed32Value);
+                        break;
+                    case TYPE_BOOL:
+                        Boolean boolValue = (Boolean) value;
+                        output.writeBoolNoTag(boolValue);
+                        break;
+                    case TYPE_STRING:
+                        String stringValue = (String) value;
+                        output.writeStringNoTag(stringValue);
+                        break;
+                    case TYPE_BYTES:
+                        byte[] bytesValue = (byte[]) value;
+                        output.writeBytesNoTag(bytesValue);
+                        break;
+                    case TYPE_UINT32:
+                        Integer uint32Value = (Integer) value;
+                        output.writeUInt32NoTag(uint32Value);
+                        break;
+                    case TYPE_ENUM:
+                        Integer enumValue = (Integer) value;
+                        output.writeEnumNoTag(enumValue);
+                        break;
+                    case TYPE_SFIXED32:
+                        Integer sfixed32Value = (Integer) value;
+                        output.writeSFixed32NoTag(sfixed32Value);
+                        break;
+                    case TYPE_SFIXED64:
+                        Long sfixed64Value = (Long) value;
+                        output.writeSFixed64NoTag(sfixed64Value);
+                        break;
+                    case TYPE_SINT32:
+                        Integer sint32Value = (Integer) value;
+                        output.writeSInt32NoTag(sint32Value);
+                        break;
+                    case TYPE_SINT64:
+                        Long sint64Value = (Long) value;
+                        output.writeSInt64NoTag(sint64Value);
+                        break;
+                    default:
+                        throw new IllegalArgumentException("Unknown type " + type);
+                }
+            } catch (IOException e) {
+                // Should not happen
+                throw new IllegalStateException(e);
+            }
+        }
+
+        @Override
+        protected void writeRepeatedData(Object array, CodedOutputByteBufferNano output) {
+            if (tag == nonPackedTag) {
+                // Use base implementation for non-packed data
+                super.writeRepeatedData(array, output);
+            } else if (tag == packedTag) {
+                // Packed. Note that the array element type is guaranteed to be primitive, so there
+                // won't be any null elements, so no null check in this block.
+                int arrayLength = Array.getLength(array);
+                int dataSize = computePackedDataSize(array);
+
+                try {
+                    output.writeRawVarint32(tag);
+                    output.writeRawVarint32(dataSize);
+                    switch (type) {
+                        case TYPE_BOOL:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeBoolNoTag(Array.getBoolean(array, i));
+                            }
+                            break;
+                        case TYPE_FIXED32:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeFixed32NoTag(Array.getInt(array, i));
+                            }
+                            break;
+                        case TYPE_SFIXED32:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeSFixed32NoTag(Array.getInt(array, i));
+                            }
+                            break;
+                        case TYPE_FLOAT:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeFloatNoTag(Array.getFloat(array, i));
+                            }
+                            break;
+                        case TYPE_FIXED64:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeFixed64NoTag(Array.getLong(array, i));
+                            }
+                            break;
+                        case TYPE_SFIXED64:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeSFixed64NoTag(Array.getLong(array, i));
+                            }
+                            break;
+                        case TYPE_DOUBLE:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeDoubleNoTag(Array.getDouble(array, i));
+                            }
+                            break;
+                        case TYPE_INT32:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeInt32NoTag(Array.getInt(array, i));
+                            }
+                            break;
+                        case TYPE_SINT32:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeSInt32NoTag(Array.getInt(array, i));
+                            }
+                            break;
+                        case TYPE_UINT32:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeUInt32NoTag(Array.getInt(array, i));
+                            }
+                            break;
+                        case TYPE_INT64:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeInt64NoTag(Array.getLong(array, i));
+                            }
+                            break;
+                        case TYPE_SINT64:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeSInt64NoTag(Array.getLong(array, i));
+                            }
+                            break;
+                        case TYPE_UINT64:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeUInt64NoTag(Array.getLong(array, i));
+                            }
+                            break;
+                        case TYPE_ENUM:
+                            for (int i = 0; i < arrayLength; i++) {
+                                output.writeEnumNoTag(Array.getInt(array, i));
+                            }
+                            break;
+                        default:
+                            throw new IllegalArgumentException("Unpackable type " + type);
+                    }
+                } catch (IOException e) {
+                    // Should not happen.
+                    throw new IllegalStateException(e);
+                }
+            } else {
+                throw new IllegalArgumentException("Unexpected repeated extension tag " + tag
+                        + ", unequal to both non-packed variant " + nonPackedTag
+                        + " and packed variant " + packedTag);
+            }
+        }
+
+        private int computePackedDataSize(Object array) {
+            int dataSize = 0;
+            int arrayLength = Array.getLength(array);
+            switch (type) {
+                case TYPE_BOOL:
+                    // Bools are stored as int32 but just as 0 or 1, so 1 byte each.
+                    dataSize = arrayLength;
+                    break;
+                case TYPE_FIXED32:
+                case TYPE_SFIXED32:
+                case TYPE_FLOAT:
+                    dataSize = arrayLength * CodedOutputByteBufferNano.LITTLE_ENDIAN_32_SIZE;
+                    break;
+                case TYPE_FIXED64:
+                case TYPE_SFIXED64:
+                case TYPE_DOUBLE:
+                    dataSize = arrayLength * CodedOutputByteBufferNano.LITTLE_ENDIAN_64_SIZE;
+                    break;
+                case TYPE_INT32:
+                    for (int i = 0; i < arrayLength; i++) {
+                        dataSize += CodedOutputByteBufferNano.computeInt32SizeNoTag(
+                                Array.getInt(array, i));
+                    }
+                    break;
+                case TYPE_SINT32:
+                    for (int i = 0; i < arrayLength; i++) {
+                        dataSize += CodedOutputByteBufferNano.computeSInt32SizeNoTag(
+                                Array.getInt(array, i));
+                    }
+                    break;
+                case TYPE_UINT32:
+                    for (int i = 0; i < arrayLength; i++) {
+                        dataSize += CodedOutputByteBufferNano.computeUInt32SizeNoTag(
+                                Array.getInt(array, i));
+                    }
+                    break;
+                case TYPE_INT64:
+                    for (int i = 0; i < arrayLength; i++) {
+                        dataSize += CodedOutputByteBufferNano.computeInt64SizeNoTag(
+                                Array.getLong(array, i));
+                    }
+                    break;
+                case TYPE_SINT64:
+                    for (int i = 0; i < arrayLength; i++) {
+                        dataSize += CodedOutputByteBufferNano.computeSInt64SizeNoTag(
+                                Array.getLong(array, i));
+                    }
+                    break;
+                case TYPE_UINT64:
+                    for (int i = 0; i < arrayLength; i++) {
+                        dataSize += CodedOutputByteBufferNano.computeUInt64SizeNoTag(
+                                Array.getLong(array, i));
+                    }
+                    break;
+                case TYPE_ENUM:
+                    for (int i = 0; i < arrayLength; i++) {
+                        dataSize += CodedOutputByteBufferNano.computeEnumSizeNoTag(
+                                Array.getInt(array, i));
+                    }
+                    break;
+                default:
+                    throw new IllegalArgumentException("Unexpected non-packable type " + type);
+            }
+            return dataSize;
+        }
+
+        @Override
+        protected int computeRepeatedSerializedSize(Object array) {
+            if (tag == nonPackedTag) {
+                // Use base implementation for non-packed data
+                return super.computeRepeatedSerializedSize(array);
+            } else if (tag == packedTag) {
+                // Packed.
+                int dataSize = computePackedDataSize(array);
+                int payloadSize =
+                        dataSize + CodedOutputByteBufferNano.computeRawVarint32Size(dataSize);
+                return payloadSize + CodedOutputByteBufferNano.computeRawVarint32Size(tag);
+            } else {
+                throw new IllegalArgumentException("Unexpected repeated extension tag " + tag
+                        + ", unequal to both non-packed variant " + nonPackedTag
+                        + " and packed variant " + packedTag);
+            }
+        }
+
+        @Override
+        protected final int computeSingularSerializedSize(Object value) {
+            int fieldNumber = WireFormatNano.getTagFieldNumber(tag);
+            switch (type) {
+                case TYPE_DOUBLE:
+                    Double doubleValue = (Double) value;
+                    return CodedOutputByteBufferNano.computeDoubleSize(fieldNumber, doubleValue);
+                case TYPE_FLOAT:
+                    Float floatValue = (Float) value;
+                    return CodedOutputByteBufferNano.computeFloatSize(fieldNumber, floatValue);
+                case TYPE_INT64:
+                    Long int64Value = (Long) value;
+                    return CodedOutputByteBufferNano.computeInt64Size(fieldNumber, int64Value);
+                case TYPE_UINT64:
+                    Long uint64Value = (Long) value;
+                    return CodedOutputByteBufferNano.computeUInt64Size(fieldNumber, uint64Value);
+                case TYPE_INT32:
+                    Integer int32Value = (Integer) value;
+                    return CodedOutputByteBufferNano.computeInt32Size(fieldNumber, int32Value);
+                case TYPE_FIXED64:
+                    Long fixed64Value = (Long) value;
+                    return CodedOutputByteBufferNano.computeFixed64Size(fieldNumber, fixed64Value);
+                case TYPE_FIXED32:
+                    Integer fixed32Value = (Integer) value;
+                    return CodedOutputByteBufferNano.computeFixed32Size(fieldNumber, fixed32Value);
+                case TYPE_BOOL:
+                    Boolean boolValue = (Boolean) value;
+                    return CodedOutputByteBufferNano.computeBoolSize(fieldNumber, boolValue);
+                case TYPE_STRING:
+                    String stringValue = (String) value;
+                    return CodedOutputByteBufferNano.computeStringSize(fieldNumber, stringValue);
+                case TYPE_BYTES:
+                    byte[] bytesValue = (byte[]) value;
+                    return CodedOutputByteBufferNano.computeBytesSize(fieldNumber, bytesValue);
+                case TYPE_UINT32:
+                    Integer uint32Value = (Integer) value;
+                    return CodedOutputByteBufferNano.computeUInt32Size(fieldNumber, uint32Value);
+                case TYPE_ENUM:
+                    Integer enumValue = (Integer) value;
+                    return CodedOutputByteBufferNano.computeEnumSize(fieldNumber, enumValue);
+                case TYPE_SFIXED32:
+                    Integer sfixed32Value = (Integer) value;
+                    return CodedOutputByteBufferNano.computeSFixed32Size(fieldNumber,
+                            sfixed32Value);
+                case TYPE_SFIXED64:
+                    Long sfixed64Value = (Long) value;
+                    return CodedOutputByteBufferNano.computeSFixed64Size(fieldNumber,
+                            sfixed64Value);
+                case TYPE_SINT32:
+                    Integer sint32Value = (Integer) value;
+                    return CodedOutputByteBufferNano.computeSInt32Size(fieldNumber, sint32Value);
+                case TYPE_SINT64:
+                    Long sint64Value = (Long) value;
+                    return CodedOutputByteBufferNano.computeSInt64Size(fieldNumber, sint64Value);
+                default:
+                    throw new IllegalArgumentException("Unknown type " + type);
+            }
+        }
+    }
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/FieldArray.java b/javanano/src/main/java/com/google/protobuf/nano/FieldArray.java
new file mode 100644
index 00000000..ab923a4d
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/FieldArray.java
@@ -0,0 +1,273 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2014 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+
+/**
+ * A custom version of {@link android.util.SparseArray} with the minimal API
+ * for storing {@link FieldData} objects.
+ *
+ * Based on {@link android.support.v4.util.SpareArrayCompat}.
+ */
+class FieldArray {
+    private static final FieldData DELETED = new FieldData();
+    private boolean mGarbage = false;
+
+    private int[] mFieldNumbers;
+    private FieldData[] mData;
+    private int mSize;
+
+    /**
+     * Creates a new FieldArray containing no fields.
+     */
+    public FieldArray() {
+        this(10);
+    }
+
+    /**
+     * Creates a new FieldArray containing no mappings that will not
+     * require any additional memory allocation to store the specified
+     * number of mappings.
+     */
+    public FieldArray(int initialCapacity) {
+        initialCapacity = idealIntArraySize(initialCapacity);
+        mFieldNumbers = new int[initialCapacity];
+        mData = new FieldData[initialCapacity];
+        mSize = 0;
+    }
+
+    /**
+     * Gets the FieldData mapped from the specified fieldNumber, or <code>null</code>
+     * if no such mapping has been made.
+     */
+    public FieldData get(int fieldNumber) {
+        int i = binarySearch(fieldNumber);
+
+        if (i < 0 || mData[i] == DELETED) {
+            return null;
+        } else {
+            return mData[i];
+        }
+    }
+
+    /**
+     * Removes the data from the specified fieldNumber, if there was any.
+     */
+    public void remove(int fieldNumber) {
+        int i = binarySearch(fieldNumber);
+
+        if (i >= 0 && mData[i] != DELETED) {
+            mData[i] = DELETED;
+            mGarbage = true;
+        }
+    }
+
+    private void gc() {
+        int n = mSize;
+        int o = 0;
+        int[] keys = mFieldNumbers;
+        FieldData[] values = mData;
+
+        for (int i = 0; i < n; i++) {
+            FieldData val = values[i];
+
+            if (val != DELETED) {
+                if (i != o) {
+                    keys[o] = keys[i];
+                    values[o] = val;
+                    values[i] = null;
+                }
+
+                o++;
+            }
+        }
+
+        mGarbage = false;
+        mSize = o;
+    }
+
+    /**
+     * Adds a mapping from the specified fieldNumber to the specified data,
+     * replacing the previous mapping if there was one.
+     */
+    public void put(int fieldNumber, FieldData data) {
+        int i = binarySearch(fieldNumber);
+
+        if (i >= 0) {
+            mData[i] = data;
+        } else {
+            i = ~i;
+
+            if (i < mSize && mData[i] == DELETED) {
+                mFieldNumbers[i] = fieldNumber;
+                mData[i] = data;
+                return;
+            }
+
+            if (mGarbage && mSize >= mFieldNumbers.length) {
+                gc();
+
+                // Search again because indices may have changed.
+                i = ~ binarySearch(fieldNumber);
+            }
+
+            if (mSize >= mFieldNumbers.length) {
+                int n = idealIntArraySize(mSize + 1);
+
+                int[] nkeys = new int[n];
+                FieldData[] nvalues = new FieldData[n];
+
+                System.arraycopy(mFieldNumbers, 0, nkeys, 0, mFieldNumbers.length);
+                System.arraycopy(mData, 0, nvalues, 0, mData.length);
+
+                mFieldNumbers = nkeys;
+                mData = nvalues;
+            }
+
+            if (mSize - i != 0) {
+                System.arraycopy(mFieldNumbers, i, mFieldNumbers, i + 1, mSize - i);
+                System.arraycopy(mData, i, mData, i + 1, mSize - i);
+            }
+
+            mFieldNumbers[i] = fieldNumber;
+            mData[i] = data;
+            mSize++;
+        }
+    }
+
+    /**
+     * Returns the number of key-value mappings that this FieldArray
+     * currently stores.
+     */
+    public int size() {
+        if (mGarbage) {
+            gc();
+        }
+
+        return mSize;
+    }
+
+    public boolean isEmpty() {
+        return size() == 0;
+    }
+
+    /**
+     * Given an index in the range <code>0...size()-1</code>, returns
+     * the value from the <code>index</code>th key-value mapping that this
+     * FieldArray stores.
+     */
+    public FieldData dataAt(int index) {
+        if (mGarbage) {
+            gc();
+        }
+
+        return mData[index];
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == this) {
+            return true;
+        }
+        if (!(o instanceof FieldArray)) {
+            return false;
+        }
+
+        FieldArray other = (FieldArray) o;
+        if (size() != other.size()) {  // size() will call gc() if necessary.
+            return false;
+        }
+        return arrayEquals(mFieldNumbers, other.mFieldNumbers, mSize) &&
+                arrayEquals(mData, other.mData, mSize);
+    }
+
+    @Override
+    public int hashCode() {
+        if (mGarbage) {
+            gc();
+        }
+        int result = 17;
+        for (int i = 0; i < mSize; i++) {
+            result = 31 * result + mFieldNumbers[i];
+            result = 31 * result + mData[i].hashCode();
+        }
+        return result;
+    }
+
+    private int idealIntArraySize(int need) {
+        return idealByteArraySize(need * 4) / 4;
+    }
+
+    private int idealByteArraySize(int need) {
+        for (int i = 4; i < 32; i++)
+            if (need <= (1 << i) - 12)
+                return (1 << i) - 12;
+
+        return need;
+    }
+
+    private int binarySearch(int value) {
+        int lo = 0;
+        int hi = mSize - 1;
+
+        while (lo <= hi) {
+            int mid = (lo + hi) >>> 1;
+            int midVal = mFieldNumbers[mid];
+
+            if (midVal < value) {
+                lo = mid + 1;
+            } else if (midVal > value) {
+                hi = mid - 1;
+            } else {
+                return mid; // value found
+            }
+        }
+        return ~lo; // value not present
+    }
+
+    private boolean arrayEquals(int[] a, int[] b, int size) {
+        for (int i = 0; i < size; i++) {
+            if (a[i] != b[i]) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private boolean arrayEquals(FieldData[] a, FieldData[] b, int size) {
+        for (int i = 0; i < size; i++) {
+            if (!a[i].equals(b[i])) {
+                return false;
+            }
+        }
+        return true;
+    }
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/FieldData.java b/javanano/src/main/java/com/google/protobuf/nano/FieldData.java
new file mode 100644
index 00000000..e5b69aad
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/FieldData.java
@@ -0,0 +1,190 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2014 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Stores unknown fields. These might be extensions or fields that the generated API doesn't
+ * know about yet.
+ */
+class FieldData {
+    private Extension<?, ?> cachedExtension;
+    private Object value;
+    /** The serialised values for this object. Will be cleared if getValue is called */
+    private List<UnknownFieldData> unknownFieldData;
+
+    <T> FieldData(Extension<?, T> extension, T newValue) {
+        cachedExtension = extension;
+        value = newValue;
+    }
+
+    FieldData() {
+        unknownFieldData = new ArrayList<UnknownFieldData>();
+    }
+
+    void addUnknownField(UnknownFieldData unknownField) {
+        unknownFieldData.add(unknownField);
+    }
+
+    UnknownFieldData getUnknownField(int index) {
+        if (unknownFieldData == null) {
+            return null;
+        }
+        if (index < unknownFieldData.size()) {
+            return unknownFieldData.get(index);
+        }
+        return null;
+    }
+
+    int getUnknownFieldSize() {
+        if (unknownFieldData == null) {
+            return 0;
+        }
+        return unknownFieldData.size();
+    }
+
+    <T> T getValue(Extension<?, T> extension) {
+        if (value != null){
+            if (cachedExtension != extension) {  // Extension objects are singletons.
+                throw new IllegalStateException(
+                        "Tried to getExtension with a differernt Extension.");
+            }
+        } else {
+            cachedExtension = extension;
+            value = extension.getValueFrom(unknownFieldData);
+            unknownFieldData = null;
+        }
+        return (T) value;
+    }
+
+    <T> void setValue(Extension<?, T> extension, T newValue) {
+        cachedExtension = extension;
+        value = newValue;
+        unknownFieldData = null;
+    }
+
+    int computeSerializedSize() {
+        int size = 0;
+        if (value != null) {
+            size = cachedExtension.computeSerializedSize(value);
+        } else {
+            for (UnknownFieldData unknownField : unknownFieldData) {
+                size += unknownField.computeSerializedSize();
+            }
+        }
+        return size;
+    }
+
+    void writeTo(CodedOutputByteBufferNano output) throws IOException {
+        if (value != null) {
+            cachedExtension.writeTo(value, output);
+        } else {
+            for (UnknownFieldData unknownField : unknownFieldData) {
+                unknownField.writeTo(output);
+            }
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == this) {
+            return true;
+        }
+        if (!(o instanceof FieldData)) {
+            return false;
+        }
+
+        FieldData other = (FieldData) o;
+        if (value != null && other.value != null) {
+            // If both objects have deserialized values, compare those.
+            // Since unknown fields are only compared if messages have generated equals methods
+            // we know this will be a meaningful comparison (not identity) for all values.
+            if (cachedExtension != other.cachedExtension) {  // Extension objects are singletons.
+                return false;
+            }
+            if (!cachedExtension.clazz.isArray()) {
+                // Can't test (!cachedExtension.repeated) due to 'bytes' -> 'byte[]'
+                return value.equals(other.value);
+            }
+            if (value instanceof byte[]) {
+                return Arrays.equals((byte[]) value, (byte[]) other.value);
+            } else if (value instanceof int[]) {
+                return Arrays.equals((int[]) value, (int[]) other.value);
+            } else if (value instanceof long[]) {
+                return Arrays.equals((long[]) value, (long[]) other.value);
+            } else if (value instanceof float[]) {
+                return Arrays.equals((float[]) value, (float[]) other.value);
+            } else if (value instanceof double[]) {
+                return Arrays.equals((double[]) value, (double[]) other.value);
+            } else if (value instanceof boolean[]) {
+                return Arrays.equals((boolean[]) value, (boolean[]) other.value);
+            } else {
+                return Arrays.deepEquals((Object[]) value, (Object[]) other.value);
+            }
+        }
+        if (unknownFieldData != null && other.unknownFieldData != null) {
+            // If both objects have byte arrays compare those directly.
+            return unknownFieldData.equals(other.unknownFieldData);
+        }
+        try {
+            // As a last resort, serialize and compare the resulting byte arrays.
+            return Arrays.equals(toByteArray(), other.toByteArray());
+        } catch (IOException e) {
+            // Should not happen.
+            throw new IllegalStateException(e);
+        }
+    }
+
+    @Override
+    public int hashCode() {
+        int result = 17;
+        try {
+            // The only way to generate a consistent hash is to use the serialized form.
+            result = 31 * result + Arrays.hashCode(toByteArray());
+        } catch (IOException e) {
+            // Should not happen.
+            throw new IllegalStateException(e);
+        }
+        return result;
+    }
+
+    private byte[] toByteArray() throws IOException {
+        byte[] result = new byte[computeSerializedSize()];
+        CodedOutputByteBufferNano output = CodedOutputByteBufferNano.newInstance(result);
+        writeTo(output);
+        return result;
+    }
+
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/InternalNano.java b/javanano/src/main/java/com/google/protobuf/nano/InternalNano.java
new file mode 100644
index 00000000..90ca11d5
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/InternalNano.java
@@ -0,0 +1,333 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.io.UnsupportedEncodingException;
+import java.util.Arrays;
+
+/**
+ * The classes contained within are used internally by the Protocol Buffer
+ * library and generated message implementations. They are public only because
+ * those generated messages do not reside in the {@code protobuf} package.
+ * Others should not use this class directly.
+ *
+ * @author kenton@google.com (Kenton Varda)
+ */
+public final class InternalNano {
+
+  private InternalNano() {}
+
+  /**
+   * An object to provide synchronization when lazily initializing static fields
+   * of {@link MessageNano} subclasses.
+   * <p>
+   * To enable earlier versions of ProGuard to inline short methods from a
+   * generated MessageNano subclass to the call sites, that class must not have
+   * a class initializer, which will be created if there is any static variable
+   * initializers. To lazily initialize the static variables in a thread-safe
+   * manner, the initialization code will synchronize on this object.
+   */
+  public static final Object LAZY_INIT_LOCK = new Object();
+
+  /**
+   * Helper called by generated code to construct default values for string
+   * fields.
+   * <p>
+   * The protocol compiler does not actually contain a UTF-8 decoder -- it
+   * just pushes UTF-8-encoded text around without touching it.  The one place
+   * where this presents a problem is when generating Java string literals.
+   * Unicode characters in the string literal would normally need to be encoded
+   * using a Unicode escape sequence, which would require decoding them.
+   * To get around this, protoc instead embeds the UTF-8 bytes into the
+   * generated code and leaves it to the runtime library to decode them.
+   * <p>
+   * It gets worse, though.  If protoc just generated a byte array, like:
+   *   new byte[] {0x12, 0x34, 0x56, 0x78}
+   * Java actually generates *code* which allocates an array and then fills
+   * in each value.  This is much less efficient than just embedding the bytes
+   * directly into the bytecode.  To get around this, we need another
+   * work-around.  String literals are embedded directly, so protoc actually
+   * generates a string literal corresponding to the bytes.  The easiest way
+   * to do this is to use the ISO-8859-1 character set, which corresponds to
+   * the first 256 characters of the Unicode range.  Protoc can then use
+   * good old CEscape to generate the string.
+   * <p>
+   * So we have a string literal which represents a set of bytes which
+   * represents another string.  This function -- stringDefaultValue --
+   * converts from the generated string to the string we actually want.  The
+   * generated code calls this automatically.
+   */
+  public static String stringDefaultValue(String bytes) {
+    try {
+      return new String(bytes.getBytes("ISO-8859-1"), "UTF-8");
+    } catch (UnsupportedEncodingException e) {
+      // This should never happen since all JVMs are required to implement
+      // both of the above character sets.
+      throw new IllegalStateException(
+          "Java VM does not support a standard character set.", e);
+    }
+  }
+
+  /**
+   * Helper called by generated code to construct default values for bytes
+   * fields.
+   * <p>
+   * This is a lot like {@link #stringDefaultValue}, but for bytes fields.
+   * In this case we only need the second of the two hacks -- allowing us to
+   * embed raw bytes as a string literal with ISO-8859-1 encoding.
+   */
+  public static byte[] bytesDefaultValue(String bytes) {
+    try {
+      return bytes.getBytes("ISO-8859-1");
+    } catch (UnsupportedEncodingException e) {
+      // This should never happen since all JVMs are required to implement
+      // ISO-8859-1.
+      throw new IllegalStateException(
+          "Java VM does not support a standard character set.", e);
+    }
+  }
+
+  /**
+   * Helper function to convert a string into UTF-8 while turning the
+   * UnsupportedEncodingException to a RuntimeException.
+   */
+  public static byte[] copyFromUtf8(final String text) {
+    try {
+      return text.getBytes("UTF-8");
+    } catch (UnsupportedEncodingException e) {
+      throw new RuntimeException("UTF-8 not supported?");
+    }
+  }
+
+  /**
+   * Checks repeated int field equality; null-value and 0-length fields are
+   * considered equal.
+   */
+  public static boolean equals(int[] field1, int[] field2) {
+    if (field1 == null || field1.length == 0) {
+      return field2 == null || field2.length == 0;
+    } else {
+      return Arrays.equals(field1, field2);
+    }
+  }
+
+  /**
+   * Checks repeated long field equality; null-value and 0-length fields are
+   * considered equal.
+   */
+  public static boolean equals(long[] field1, long[] field2) {
+    if (field1 == null || field1.length == 0) {
+      return field2 == null || field2.length == 0;
+    } else {
+      return Arrays.equals(field1, field2);
+    }
+  }
+
+  /**
+   * Checks repeated float field equality; null-value and 0-length fields are
+   * considered equal.
+   */
+  public static boolean equals(float[] field1, float[] field2) {
+    if (field1 == null || field1.length == 0) {
+      return field2 == null || field2.length == 0;
+    } else {
+      return Arrays.equals(field1, field2);
+    }
+  }
+
+  /**
+   * Checks repeated double field equality; null-value and 0-length fields are
+   * considered equal.
+   */
+  public static boolean equals(double[] field1, double[] field2) {
+    if (field1 == null || field1.length == 0) {
+      return field2 == null || field2.length == 0;
+    } else {
+      return Arrays.equals(field1, field2);
+    }
+  }
+
+  /**
+   * Checks repeated boolean field equality; null-value and 0-length fields are
+   * considered equal.
+   */
+  public static boolean equals(boolean[] field1, boolean[] field2) {
+    if (field1 == null || field1.length == 0) {
+      return field2 == null || field2.length == 0;
+    } else {
+      return Arrays.equals(field1, field2);
+    }
+  }
+
+  /**
+   * Checks repeated bytes field equality. Only non-null elements are tested.
+   * Returns true if the two fields have the same sequence of non-null
+   * elements. Null-value fields and fields of any length with only null
+   * elements are considered equal.
+   */
+  public static boolean equals(byte[][] field1, byte[][] field2) {
+    int index1 = 0;
+    int length1 = field1 == null ? 0 : field1.length;
+    int index2 = 0;
+    int length2 = field2 == null ? 0 : field2.length;
+    while (true) {
+      while (index1 < length1 && field1[index1] == null) {
+        index1++;
+      }
+      while (index2 < length2 && field2[index2] == null) {
+        index2++;
+      }
+      boolean atEndOf1 = index1 >= length1;
+      boolean atEndOf2 = index2 >= length2;
+      if (atEndOf1 && atEndOf2) {
+        // no more non-null elements to test in both arrays
+        return true;
+      } else if (atEndOf1 != atEndOf2) {
+        // one of the arrays have extra non-null elements
+        return false;
+      } else if (!Arrays.equals(field1[index1], field2[index2])) {
+        // element mismatch
+        return false;
+      }
+      index1++;
+      index2++;
+    }
+  }
+
+  /**
+   * Checks repeated string/message field equality. Only non-null elements are
+   * tested. Returns true if the two fields have the same sequence of non-null
+   * elements. Null-value fields and fields of any length with only null
+   * elements are considered equal.
+   */
+  public static boolean equals(Object[] field1, Object[] field2) {
+    int index1 = 0;
+    int length1 = field1 == null ? 0 : field1.length;
+    int index2 = 0;
+    int length2 = field2 == null ? 0 : field2.length;
+    while (true) {
+      while (index1 < length1 && field1[index1] == null) {
+        index1++;
+      }
+      while (index2 < length2 && field2[index2] == null) {
+        index2++;
+      }
+      boolean atEndOf1 = index1 >= length1;
+      boolean atEndOf2 = index2 >= length2;
+      if (atEndOf1 && atEndOf2) {
+        // no more non-null elements to test in both arrays
+        return true;
+      } else if (atEndOf1 != atEndOf2) {
+        // one of the arrays have extra non-null elements
+        return false;
+      } else if (!field1[index1].equals(field2[index2])) {
+        // element mismatch
+        return false;
+      }
+      index1++;
+      index2++;
+    }
+  }
+
+  /**
+   * Computes the hash code of a repeated int field. Null-value and 0-length
+   * fields have the same hash code.
+   */
+  public static int hashCode(int[] field) {
+    return field == null || field.length == 0 ? 0 : Arrays.hashCode(field);
+  }
+
+  /**
+   * Computes the hash code of a repeated long field. Null-value and 0-length
+   * fields have the same hash code.
+   */
+  public static int hashCode(long[] field) {
+    return field == null || field.length == 0 ? 0 : Arrays.hashCode(field);
+  }
+
+  /**
+   * Computes the hash code of a repeated float field. Null-value and 0-length
+   * fields have the same hash code.
+   */
+  public static int hashCode(float[] field) {
+    return field == null || field.length == 0 ? 0 : Arrays.hashCode(field);
+  }
+
+  /**
+   * Computes the hash code of a repeated double field. Null-value and 0-length
+   * fields have the same hash code.
+   */
+  public static int hashCode(double[] field) {
+    return field == null || field.length == 0 ? 0 : Arrays.hashCode(field);
+  }
+
+  /**
+   * Computes the hash code of a repeated boolean field. Null-value and 0-length
+   * fields have the same hash code.
+   */
+  public static int hashCode(boolean[] field) {
+    return field == null || field.length == 0 ? 0 : Arrays.hashCode(field);
+  }
+
+  /**
+   * Computes the hash code of a repeated bytes field. Only the sequence of all
+   * non-null elements are used in the computation. Null-value fields and fields
+   * of any length with only null elements have the same hash code.
+   */
+  public static int hashCode(byte[][] field) {
+    int result = 0;
+    for (int i = 0, size = field == null ? 0 : field.length; i < size; i++) {
+      byte[] element = field[i];
+      if (element != null) {
+        result = 31 * result + Arrays.hashCode(element);
+      }
+    }
+    return result;
+  }
+
+  /**
+   * Computes the hash code of a repeated string/message field. Only the
+   * sequence of all non-null elements are used in the computation. Null-value
+   * fields and fields of any length with only null elements have the same hash
+   * code.
+   */
+  public static int hashCode(Object[] field) {
+    int result = 0;
+    for (int i = 0, size = field == null ? 0 : field.length; i < size; i++) {
+      Object element = field[i];
+      if (element != null) {
+        result = 31 * result + element.hashCode();
+      }
+    }
+    return result;
+  }
+
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/InvalidProtocolBufferNanoException.java b/javanano/src/main/java/com/google/protobuf/nano/InvalidProtocolBufferNanoException.java
new file mode 100644
index 00000000..ff0af9df
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/InvalidProtocolBufferNanoException.java
@@ -0,0 +1,93 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.io.IOException;
+
+/**
+ * Thrown when a protocol message being parsed is invalid in some way,
+ * e.g. it contains a malformed varint or a negative byte length.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+public class InvalidProtocolBufferNanoException extends IOException {
+  private static final long serialVersionUID = -1616151763072450476L;
+
+  public InvalidProtocolBufferNanoException(final String description) {
+    super(description);
+  }
+
+  static InvalidProtocolBufferNanoException truncatedMessage() {
+    return new InvalidProtocolBufferNanoException(
+      "While parsing a protocol message, the input ended unexpectedly " +
+      "in the middle of a field.  This could mean either than the " +
+      "input has been truncated or that an embedded message " +
+      "misreported its own length.");
+  }
+
+  static InvalidProtocolBufferNanoException negativeSize() {
+    return new InvalidProtocolBufferNanoException(
+      "CodedInputStream encountered an embedded string or message " +
+      "which claimed to have negative size.");
+  }
+
+  static InvalidProtocolBufferNanoException malformedVarint() {
+    return new InvalidProtocolBufferNanoException(
+      "CodedInputStream encountered a malformed varint.");
+  }
+
+  static InvalidProtocolBufferNanoException invalidTag() {
+    return new InvalidProtocolBufferNanoException(
+      "Protocol message contained an invalid tag (zero).");
+  }
+
+  static InvalidProtocolBufferNanoException invalidEndTag() {
+    return new InvalidProtocolBufferNanoException(
+      "Protocol message end-group tag did not match expected tag.");
+  }
+
+  static InvalidProtocolBufferNanoException invalidWireType() {
+    return new InvalidProtocolBufferNanoException(
+      "Protocol message tag had invalid wire type.");
+  }
+
+  static InvalidProtocolBufferNanoException recursionLimitExceeded() {
+    return new InvalidProtocolBufferNanoException(
+      "Protocol message had too many levels of nesting.  May be malicious.  " +
+      "Use CodedInputStream.setRecursionLimit() to increase the depth limit.");
+  }
+
+  static InvalidProtocolBufferNanoException sizeLimitExceeded() {
+    return new InvalidProtocolBufferNanoException(
+      "Protocol message was too large.  May be malicious.  " +
+      "Use CodedInputStream.setSizeLimit() to increase the size limit.");
+  }
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/MessageNano.java b/javanano/src/main/java/com/google/protobuf/nano/MessageNano.java
new file mode 100644
index 00000000..164f317f
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/MessageNano.java
@@ -0,0 +1,190 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.io.IOException;
+import java.util.Arrays;
+
+/**
+ * Abstract interface implemented by Protocol Message objects.
+ *
+ * @author wink@google.com Wink Saville
+ */
+public abstract class MessageNano {
+    protected volatile int cachedSize = -1;
+
+    /**
+     * Get the number of bytes required to encode this message.
+     * Returns the cached size or calls getSerializedSize which
+     * sets the cached size. This is used internally when serializing
+     * so the size is only computed once. If a member is modified
+     * then this could be stale call getSerializedSize if in doubt.
+     */
+    public int getCachedSize() {
+        if (cachedSize < 0) {
+            // getSerializedSize sets cachedSize
+            getSerializedSize();
+        }
+        return cachedSize;
+    }
+
+    /**
+     * Computes the number of bytes required to encode this message.
+     * The size is cached and the cached result can be retrieved
+     * using getCachedSize().
+     */
+    public int getSerializedSize() {
+        int size = computeSerializedSize();
+        cachedSize = size;
+        return size;
+    }
+
+    /**
+     * Computes the number of bytes required to encode this message. This does not update the
+     * cached size.
+     */
+    protected int computeSerializedSize() {
+      // This is overridden if the generated message has serialized fields.
+      return 0;
+    }
+
+    /**
+     * Serializes the message and writes it to {@code output}.
+     *
+     * @param output the output to receive the serialized form.
+     * @throws IOException if an error occurred writing to {@code output}.
+     */
+    public void writeTo(CodedOutputByteBufferNano output) throws IOException {
+        // Does nothing by default. Overridden by subclasses which have data to write.
+    }
+
+    /**
+     * Parse {@code input} as a message of this type and merge it with the
+     * message being built.
+     */
+    public abstract MessageNano mergeFrom(CodedInputByteBufferNano input) throws IOException;
+
+    /**
+     * Serialize to a byte array.
+     * @return byte array with the serialized data.
+     */
+    public static final byte[] toByteArray(MessageNano msg) {
+        final byte[] result = new byte[msg.getSerializedSize()];
+        toByteArray(msg, result, 0, result.length);
+        return result;
+    }
+
+    /**
+     * Serialize to a byte array starting at offset through length. The
+     * method getSerializedSize must have been called prior to calling
+     * this method so the proper length is know.  If an attempt to
+     * write more than length bytes OutOfSpaceException will be thrown
+     * and if length bytes are not written then IllegalStateException
+     * is thrown.
+     */
+    public static final void toByteArray(MessageNano msg, byte[] data, int offset, int length) {
+        try {
+            final CodedOutputByteBufferNano output =
+                CodedOutputByteBufferNano.newInstance(data, offset, length);
+            msg.writeTo(output);
+            output.checkNoSpaceLeft();
+        } catch (IOException e) {
+            throw new RuntimeException("Serializing to a byte array threw an IOException "
+                    + "(should never happen).", e);
+        }
+    }
+
+    /**
+     * Parse {@code data} as a message of this type and merge it with the
+     * message being built.
+     */
+    public static final <T extends MessageNano> T mergeFrom(T msg, final byte[] data)
+        throws InvalidProtocolBufferNanoException {
+        return mergeFrom(msg, data, 0, data.length);
+    }
+
+    /**
+     * Parse {@code data} as a message of this type and merge it with the
+     * message being built.
+     */
+    public static final <T extends MessageNano> T mergeFrom(T msg, final byte[] data,
+            final int off, final int len) throws InvalidProtocolBufferNanoException {
+        try {
+            final CodedInputByteBufferNano input =
+                CodedInputByteBufferNano.newInstance(data, off, len);
+            msg.mergeFrom(input);
+            input.checkLastTagWas(0);
+            return msg;
+        } catch (InvalidProtocolBufferNanoException e) {
+            throw e;
+        } catch (IOException e) {
+            throw new RuntimeException("Reading from a byte array threw an IOException (should "
+                    + "never happen).");
+        }
+    }
+
+    /**
+     * Compares two {@code MessageNano}s and returns true if the message's are the same class and
+     * have serialized form equality (i.e. all of the field values are the same).
+     */
+    public static final boolean messageNanoEquals(MessageNano a, MessageNano b) {
+        if (a == b) {
+            return true;
+        }
+        if (a == null || b == null) {
+            return false;
+        }
+        if (a.getClass() != b.getClass()) {
+          return false;
+        }
+        final int serializedSize = a.getSerializedSize();
+        if (b.getSerializedSize() != serializedSize) {
+            return false;
+        }
+        final byte[] aByteArray = new byte[serializedSize];
+        final byte[] bByteArray = new byte[serializedSize];
+        toByteArray(a, aByteArray, 0, serializedSize);
+        toByteArray(b, bByteArray, 0, serializedSize);
+        return Arrays.equals(aByteArray, bByteArray);
+    }
+
+    /**
+     * Returns a string that is (mostly) compatible with ProtoBuffer's TextFormat. Note that groups
+     * (which are deprecated) are not serialized with the correct field name.
+     *
+     * <p>This is implemented using reflection, so it is not especially fast nor is it guaranteed
+     * to find all fields if you have method removal turned on for proguard.
+     */
+    @Override
+    public String toString() {
+        return MessageNanoPrinter.print(this);
+    }
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/MessageNanoPrinter.java b/javanano/src/main/java/com/google/protobuf/nano/MessageNanoPrinter.java
new file mode 100644
index 00000000..4cca3d5e
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/MessageNanoPrinter.java
@@ -0,0 +1,257 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.lang.reflect.Array;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+
+/**
+ * Static helper methods for printing nano protos.
+ *
+ * @author flynn@google.com Andrew Flynn
+ */
+public final class MessageNanoPrinter {
+    // Do not allow instantiation
+    private MessageNanoPrinter() {}
+
+    private static final String INDENT = "  ";
+    private static final int MAX_STRING_LEN = 200;
+
+    /**
+     * Returns an text representation of a MessageNano suitable for debugging. The returned string
+     * is mostly compatible with Protocol Buffer's TextFormat (as provided by non-nano protocol
+     * buffers) -- groups (which are deprecated) are output with an underscore name (e.g. foo_bar
+     * instead of FooBar) and will thus not parse.
+     *
+     * <p>Employs Java reflection on the given object and recursively prints primitive fields,
+     * groups, and messages.</p>
+     */
+    public static <T extends MessageNano> String print(T message) {
+        if (message == null) {
+            return "";
+        }
+
+        StringBuffer buf = new StringBuffer();
+        try {
+            print(null, message, new StringBuffer(), buf);
+        } catch (IllegalAccessException e) {
+            return "Error printing proto: " + e.getMessage();
+        } catch (InvocationTargetException e) {
+            return "Error printing proto: " + e.getMessage();
+        }
+        return buf.toString();
+    }
+
+    /**
+     * Function that will print the given message/field into the StringBuffer.
+     * Meant to be called recursively.
+     *
+     * @param identifier the identifier to use, or {@code null} if this is the root message to
+     *        print.
+     * @param object the value to print. May in fact be a primitive value or byte array and not a
+     *        message.
+     * @param indentBuf the indentation each line should begin with.
+     * @param buf the output buffer.
+     */
+    private static void print(String identifier, Object object,
+            StringBuffer indentBuf, StringBuffer buf) throws IllegalAccessException,
+            InvocationTargetException {
+        if (object == null) {
+            // This can happen if...
+            //   - we're about to print a message, String, or byte[], but it not present;
+            //   - we're about to print a primitive, but "reftype" optional style is enabled, and
+            //     the field is unset.
+            // In both cases the appropriate behavior is to output nothing.
+        } else if (object instanceof MessageNano) {  // Nano proto message
+            int origIndentBufLength = indentBuf.length();
+            if (identifier != null) {
+                buf.append(indentBuf).append(deCamelCaseify(identifier)).append(" <\n");
+                indentBuf.append(INDENT);
+            }
+            Class<?> clazz = object.getClass();
+
+            // Proto fields follow one of two formats:
+            //
+            // 1) Public, non-static variables that do not begin or end with '_'
+            // Find and print these using declared public fields
+            for (Field field : clazz.getFields()) {
+                int modifiers = field.getModifiers();
+                String fieldName = field.getName();
+
+                if ((modifiers & Modifier.PUBLIC) == Modifier.PUBLIC
+                        && (modifiers & Modifier.STATIC) != Modifier.STATIC
+                        && !fieldName.startsWith("_")
+                        && !fieldName.endsWith("_")) {
+                    Class<?> fieldType = field.getType();
+                    Object value = field.get(object);
+
+                    if (fieldType.isArray()) {
+                        Class<?> arrayType = fieldType.getComponentType();
+
+                        // bytes is special since it's not repeated, but is represented by an array
+                        if (arrayType == byte.class) {
+                            print(fieldName, value, indentBuf, buf);
+                        } else {
+                            int len = value == null ? 0 : Array.getLength(value);
+                            for (int i = 0; i < len; i++) {
+                                Object elem = Array.get(value, i);
+                                print(fieldName, elem, indentBuf, buf);
+                            }
+                        }
+                    } else {
+                        print(fieldName, value, indentBuf, buf);
+                    }
+                }
+            }
+
+            // 2) Fields that are accessed via getter methods (when accessors
+            //    mode is turned on)
+            // Find and print these using getter methods.
+            for (Method method : clazz.getMethods()) {
+                String name = method.getName();
+                // Check for the setter accessor method since getters and hazzers both have
+                // non-proto-field name collisions (hashCode() and getSerializedSize())
+                if (name.startsWith("set")) {
+                    String subfieldName = name.substring(3);
+
+                    Method hazzer = null;
+                    try {
+                        hazzer = clazz.getMethod("has" + subfieldName);
+                    } catch (NoSuchMethodException e) {
+                        continue;
+                    }
+                    // If hazzer does't exist or returns false, no need to continue
+                    if (!(Boolean) hazzer.invoke(object)) {
+                        continue;
+                    }
+
+                    Method getter = null;
+                    try {
+                        getter = clazz.getMethod("get" + subfieldName);
+                    } catch (NoSuchMethodException e) {
+                        continue;
+                    }
+
+                    print(subfieldName, getter.invoke(object), indentBuf, buf);
+                }
+            }
+            if (identifier != null) {
+                indentBuf.setLength(origIndentBufLength);
+                buf.append(indentBuf).append(">\n");
+            }
+        } else {
+            // Non-null primitive value
+            identifier = deCamelCaseify(identifier);
+            buf.append(indentBuf).append(identifier).append(": ");
+            if (object instanceof String) {
+                String stringMessage = sanitizeString((String) object);
+                buf.append("\"").append(stringMessage).append("\"");
+            } else if (object instanceof byte[]) {
+                appendQuotedBytes((byte[]) object, buf);
+            } else {
+                buf.append(object);
+            }
+            buf.append("\n");
+        }
+    }
+
+    /**
+     * Converts an identifier of the format "FieldName" into "field_name".
+     */
+    private static String deCamelCaseify(String identifier) {
+        StringBuffer out = new StringBuffer();
+        for (int i = 0; i < identifier.length(); i++) {
+            char currentChar = identifier.charAt(i);
+            if (i == 0) {
+                out.append(Character.toLowerCase(currentChar));
+            } else if (Character.isUpperCase(currentChar)) {
+                out.append('_').append(Character.toLowerCase(currentChar));
+            } else {
+                out.append(currentChar);
+            }
+        }
+        return out.toString();
+    }
+
+    /**
+     * Shortens and escapes the given string.
+     */
+    private static String sanitizeString(String str) {
+        if (!str.startsWith("http") && str.length() > MAX_STRING_LEN) {
+            // Trim non-URL strings.
+            str = str.substring(0, MAX_STRING_LEN) + "[...]";
+        }
+        return escapeString(str);
+    }
+
+    /**
+     * Escape everything except for low ASCII code points.
+     */
+    private static String escapeString(String str) {
+        int strLen = str.length();
+        StringBuilder b = new StringBuilder(strLen);
+        for (int i = 0; i < strLen; i++) {
+            char original = str.charAt(i);
+            if (original >= ' ' && original <= '~' && original != '"' && original != '\'') {
+                b.append(original);
+            } else {
+                b.append(String.format("\\u%04x", (int) original));
+            }
+        }
+        return b.toString();
+    }
+
+    /**
+     * Appends a quoted byte array to the provided {@code StringBuffer}.
+     */
+    private static void appendQuotedBytes(byte[] bytes, StringBuffer builder) {
+        if (bytes == null) {
+            builder.append("\"\"");
+            return;
+        }
+
+        builder.append('"');
+        for (int i = 0; i < bytes.length; ++i) {
+            int ch = bytes[i] & 0xff;
+            if (ch == '\\' || ch == '"') {
+                builder.append('\\').append((char) ch);
+            } else if (ch >= 32 && ch < 127) {
+                builder.append((char) ch);
+            } else {
+                builder.append(String.format("\\%03o", ch));
+            }
+        }
+        builder.append('"');
+    }
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/UnknownFieldData.java b/javanano/src/main/java/com/google/protobuf/nano/UnknownFieldData.java
new file mode 100644
index 00000000..2032e1a6
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/UnknownFieldData.java
@@ -0,0 +1,84 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.io.IOException;
+import java.util.Arrays;
+
+/**
+ * Stores unknown fields. These might be extensions or fields that the generated
+ * API doesn't know about yet.
+ *
+ * @author bduff@google.com (Brian Duff)
+ */
+final class UnknownFieldData {
+
+    final int tag;
+    final byte[] bytes;
+
+    UnknownFieldData(int tag, byte[] bytes) {
+        this.tag = tag;
+        this.bytes = bytes;
+    }
+
+    int computeSerializedSize() {
+        int size = 0;
+        size += CodedOutputByteBufferNano.computeRawVarint32Size(tag);
+        size += bytes.length;
+        return size;
+    }
+
+    void writeTo(CodedOutputByteBufferNano output) throws IOException {
+        output.writeRawVarint32(tag);
+        output.writeRawBytes(bytes);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == this) {
+            return true;
+        }
+        if (!(o instanceof UnknownFieldData)) {
+            return false;
+        }
+
+        UnknownFieldData other = (UnknownFieldData) o;
+        return tag == other.tag && Arrays.equals(bytes, other.bytes);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = 17;
+        result = 31 * result + tag;
+        result = 31 * result + Arrays.hashCode(bytes);
+        return result;
+    }
+}
diff --git a/javanano/src/main/java/com/google/protobuf/nano/WireFormatNano.java b/javanano/src/main/java/com/google/protobuf/nano/WireFormatNano.java
new file mode 100644
index 00000000..a3405e55
--- /dev/null
+++ b/javanano/src/main/java/com/google/protobuf/nano/WireFormatNano.java
@@ -0,0 +1,124 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import java.io.IOException;
+
+/**
+ * This class is used internally by the Protocol Buffer library and generated
+ * message implementations.  It is public only because those generated messages
+ * do not reside in the {@code protobuf} package.  Others should not use this
+ * class directly.
+ *
+ * This class contains constants and helper functions useful for dealing with
+ * the Protocol Buffer wire format.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+public final class WireFormatNano {
+  // Do not allow instantiation.
+  private WireFormatNano() {}
+
+  static final int WIRETYPE_VARINT           = 0;
+  static final int WIRETYPE_FIXED64          = 1;
+  static final int WIRETYPE_LENGTH_DELIMITED = 2;
+  static final int WIRETYPE_START_GROUP      = 3;
+  static final int WIRETYPE_END_GROUP        = 4;
+  static final int WIRETYPE_FIXED32          = 5;
+
+  static final int TAG_TYPE_BITS = 3;
+  static final int TAG_TYPE_MASK = (1 << TAG_TYPE_BITS) - 1;
+
+  /** Given a tag value, determines the wire type (the lower 3 bits). */
+  static int getTagWireType(final int tag) {
+    return tag & TAG_TYPE_MASK;
+  }
+
+  /** Given a tag value, determines the field number (the upper 29 bits). */
+  public static int getTagFieldNumber(final int tag) {
+    return tag >>> TAG_TYPE_BITS;
+  }
+
+  /** Makes a tag value given a field number and wire type. */
+  static int makeTag(final int fieldNumber, final int wireType) {
+    return (fieldNumber << TAG_TYPE_BITS) | wireType;
+  }
+
+  public static final int EMPTY_INT_ARRAY[] = {};
+  public static final long EMPTY_LONG_ARRAY[] = {};
+  public static final float EMPTY_FLOAT_ARRAY[] = {};
+  public static final double EMPTY_DOUBLE_ARRAY[] = {};
+  public static final boolean EMPTY_BOOLEAN_ARRAY[] = {};
+  public static final String EMPTY_STRING_ARRAY[] = {};
+  public static final byte[] EMPTY_BYTES_ARRAY[] = {};
+  public static final byte[] EMPTY_BYTES = {};
+
+  /**
+   * Parses an unknown field. This implementation skips the field.
+   *
+   * <p>Generated messages will call this for unknown fields if the store_unknown_fields
+   * option is off.
+   *
+   * @return {@literal true} unless the tag is an end-group tag.
+   */
+  public static boolean parseUnknownField(
+      final CodedInputByteBufferNano input,
+      final int tag) throws IOException {
+    return input.skipField(tag);
+  }
+
+  /**
+   * Computes the array length of a repeated field. We assume that in the common case repeated
+   * fields are contiguously serialized but we still correctly handle interspersed values of a
+   * repeated field (but with extra allocations).
+   *
+   * Rewinds to current input position before returning.
+   *
+   * @param input stream input, pointing to the byte after the first tag
+   * @param tag repeated field tag just read
+   * @return length of array
+   * @throws IOException
+   */
+  public static final int getRepeatedFieldArrayLength(
+      final CodedInputByteBufferNano input,
+      final int tag) throws IOException {
+    int arrayLength = 1;
+    int startPos = input.getPosition();
+    input.skipField(tag);
+    while (input.readTag() == tag) {
+      input.skipField(tag);
+      arrayLength++;
+    }
+    input.rewindToPosition(startPos);
+    return arrayLength;
+  }
+
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/NanoTest.java b/javanano/src/test/java/com/google/protobuf/nano/NanoTest.java
new file mode 100644
index 00000000..5ac7edb6
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/NanoTest.java
@@ -0,0 +1,3797 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2013 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.nano;
+
+import com.google.protobuf.nano.CodedInputByteBufferNano;
+import com.google.protobuf.nano.EnumClassNanoMultiple;
+import com.google.protobuf.nano.EnumClassNanos;
+import com.google.protobuf.nano.EnumValidity;
+import com.google.protobuf.nano.EnumValidityAccessors;
+import com.google.protobuf.nano.FileScopeEnumMultiple;
+import com.google.protobuf.nano.FileScopeEnumRefNano;
+import com.google.protobuf.nano.InternalNano;
+import com.google.protobuf.nano.InvalidProtocolBufferNanoException;
+import com.google.protobuf.nano.MessageNano;
+import com.google.protobuf.nano.MessageScopeEnumRefNano;
+import com.google.protobuf.nano.MultipleImportingNonMultipleNano1;
+import com.google.protobuf.nano.MultipleImportingNonMultipleNano2;
+import com.google.protobuf.nano.MultipleNameClashNano;
+import com.google.protobuf.nano.NanoAccessorsOuterClass.TestNanoAccessors;
+import com.google.protobuf.nano.NanoHasOuterClass.TestAllTypesNanoHas;
+import com.google.protobuf.nano.NanoOuterClass;
+import com.google.protobuf.nano.NanoOuterClass.TestAllTypesNano;
+import com.google.protobuf.nano.NanoReferenceTypes;
+import com.google.protobuf.nano.NanoRepeatedPackables;
+import com.google.protobuf.nano.PackedExtensions;
+import com.google.protobuf.nano.RepeatedExtensions;
+import com.google.protobuf.nano.SingularExtensions;
+import com.google.protobuf.nano.TestRepeatedMergeNano;
+import com.google.protobuf.nano.UnittestMultipleNano;
+import com.google.protobuf.nano.UnittestRecursiveNano.RecursiveMessageNano;
+import com.google.protobuf.nano.UnittestSimpleNano.SimpleMessageNano;
+import com.google.protobuf.nano.UnittestSingleNano.SingleMessageNano;
+import com.google.protobuf.nano.testext.Extensions;
+import com.google.protobuf.nano.testext.Extensions.AnotherMessage;
+import com.google.protobuf.nano.testext.Extensions.MessageWithGroup;
+import com.google.protobuf.nano.testimport.UnittestImportNano;
+
+import junit.framework.TestCase;
+
+import java.util.Arrays;
+import java.util.HashMap;
+
+/**
+ * Test nano runtime.
+ *
+ * @author ulas@google.com Ulas Kirazci
+ */
+public class NanoTest extends TestCase {
+  @Override
+  public void setUp() throws Exception {
+  }
+
+  public void testSimpleMessageNano() throws Exception {
+    SimpleMessageNano msg = new SimpleMessageNano();
+    assertEquals(123, msg.d);
+    assertEquals(null, msg.nestedMsg);
+    assertEquals(SimpleMessageNano.BAZ, msg.defaultNestedEnum);
+
+    msg.d = 456;
+    assertEquals(456, msg.d);
+
+    SimpleMessageNano.NestedMessage nestedMsg = new SimpleMessageNano.NestedMessage();
+    nestedMsg.bb = 2;
+    assertEquals(2, nestedMsg.bb);
+    msg.nestedMsg = nestedMsg;
+    assertEquals(2, msg.nestedMsg.bb);
+
+    msg.defaultNestedEnum = SimpleMessageNano.BAR;
+    assertEquals(SimpleMessageNano.BAR, msg.defaultNestedEnum);
+
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+
+    SimpleMessageNano newMsg = SimpleMessageNano.parseFrom(result);
+    assertEquals(456, newMsg.d);
+    assertEquals(2, msg.nestedMsg.bb);
+    assertEquals(SimpleMessageNano.BAR, msg.defaultNestedEnum);
+
+    msg.nestedMsg = null;
+    assertTrue(msgSerializedSize != msg.getSerializedSize());
+
+    msg.clear();
+    assertEquals(0, msg.getSerializedSize());
+  }
+
+  public void testRecursiveMessageNano() throws Exception {
+    RecursiveMessageNano msg = new RecursiveMessageNano();
+    assertTrue(msg.repeatedRecursiveMessageNano.length == 0);
+
+    RecursiveMessageNano msg1 = new RecursiveMessageNano();
+    msg1.id = 1;
+    assertEquals(1, msg1.id);
+    RecursiveMessageNano msg2 = new RecursiveMessageNano();
+    msg2.id = 2;
+    RecursiveMessageNano msg3 = new RecursiveMessageNano();
+    msg3.id = 3;
+
+    RecursiveMessageNano.NestedMessage nestedMsg = new RecursiveMessageNano.NestedMessage();
+    nestedMsg.a = msg1;
+    assertEquals(1, nestedMsg.a.id);
+
+    msg.id = 0;
+    msg.nestedMessage = nestedMsg;
+    msg.optionalRecursiveMessageNano = msg2;
+    msg.repeatedRecursiveMessageNano = new RecursiveMessageNano[] { msg3 };
+
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 16);
+    assertEquals(result.length, msgSerializedSize);
+
+    RecursiveMessageNano newMsg = RecursiveMessageNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedRecursiveMessageNano.length);
+
+    assertEquals(0, newMsg.id);
+    assertEquals(1, newMsg.nestedMessage.a.id);
+    assertEquals(2, newMsg.optionalRecursiveMessageNano.id);
+    assertEquals(3, newMsg.repeatedRecursiveMessageNano[0].id);
+  }
+
+  public void testMessageNoFields() {
+    SingleMessageNano msg = new SingleMessageNano();
+    assertEquals(0, msg.getSerializedSize());
+    assertEquals(0, MessageNano.toByteArray(msg).length);
+  }
+
+  public void testNanoRequiredInt32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.id = 123;
+    assertEquals(123, msg.id);
+    msg.clear().id = 456;
+    assertEquals(456, msg.id);
+    msg.clear();
+
+    msg.id = 123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 3);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(123, newMsg.id);
+  }
+
+  public void testNanoOptionalInt32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalInt32 = 123;
+    assertEquals(123, msg.optionalInt32);
+    msg.clear()
+       .optionalInt32 = 456;
+    assertEquals(456, msg.optionalInt32);
+    msg.clear();
+
+    msg.optionalInt32 = 123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 5);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(123, newMsg.optionalInt32);
+  }
+
+  public void testNanoOptionalInt64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalInt64 = 123;
+    assertEquals(123, msg.optionalInt64);
+    msg.clear()
+       .optionalInt64 = 456;
+    assertEquals(456, msg.optionalInt64);
+    msg.clear();
+    assertEquals(0, msg.optionalInt64);
+
+    msg.optionalInt64 = 123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 5);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(123, newMsg.optionalInt64);
+  }
+
+  public void testNanoOptionalUint32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalUint32 = 123;
+    assertEquals(123, msg.optionalUint32);
+    msg.clear()
+       .optionalUint32 = 456;
+    assertEquals(456, msg.optionalUint32);
+    msg.clear();
+    assertEquals(0, msg.optionalUint32);
+
+    msg.optionalUint32 = 123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 5);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(123, newMsg.optionalUint32);
+  }
+
+  public void testNanoOptionalUint64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalUint64 = 123;
+    assertEquals(123, msg.optionalUint64);
+    msg.clear()
+       .optionalUint64 = 456;
+    assertEquals(456, msg.optionalUint64);
+    msg.clear();
+    assertEquals(0, msg.optionalUint64);
+
+    msg.optionalUint64 = 123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 5);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(123, newMsg.optionalUint64);
+  }
+
+  public void testNanoOptionalSint32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalSint32 = 123;
+    assertEquals(123, msg.optionalSint32);
+    msg.clear()
+       .optionalSint32 = 456;
+    assertEquals(456, msg.optionalSint32);
+    msg.clear();
+    assertEquals(0, msg.optionalSint32);
+
+    msg.optionalSint32 = -123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(-123, newMsg.optionalSint32);
+  }
+
+  public void testNanoOptionalSint64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalSint64 = 123;
+    assertEquals(123, msg.optionalSint64);
+    msg.clear()
+       .optionalSint64 = 456;
+    assertEquals(456, msg.optionalSint64);
+    msg.clear();
+    assertEquals(0, msg.optionalSint64);
+
+    msg.optionalSint64 = -123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(-123, newMsg.optionalSint64);
+  }
+
+  public void testNanoOptionalFixed32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalFixed32 = 123;
+    assertEquals(123, msg.optionalFixed32);
+    msg.clear()
+       .optionalFixed32 = 456;
+    assertEquals(456, msg.optionalFixed32);
+    msg.clear();
+    assertEquals(0, msg.optionalFixed32);
+
+    msg.optionalFixed32 = 123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 8);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(123, newMsg.optionalFixed32);
+  }
+
+  public void testNanoOptionalFixed64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalFixed64 = 123;
+    assertEquals(123, msg.optionalFixed64);
+    msg.clear()
+       .optionalFixed64 = 456;
+    assertEquals(456, msg.optionalFixed64);
+    msg.clear();
+    assertEquals(0, msg.optionalFixed64);
+
+    msg.optionalFixed64 = 123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 12);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(123, newMsg.optionalFixed64);
+  }
+
+  public void testNanoOptionalSfixed32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalSfixed32 = 123;
+    assertEquals(123, msg.optionalSfixed32);
+    msg.clear()
+       .optionalSfixed32 = 456;
+    assertEquals(456, msg.optionalSfixed32);
+    msg.clear();
+    assertEquals(0, msg.optionalSfixed32);
+
+    msg.optionalSfixed32 = 123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 8);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(123, newMsg.optionalSfixed32);
+  }
+
+  public void testNanoOptionalSfixed64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalSfixed64 = 123;
+    assertEquals(123, msg.optionalSfixed64);
+    msg.clear()
+       .optionalSfixed64 = 456;
+    assertEquals(456, msg.optionalSfixed64);
+    msg.clear();
+    assertEquals(0, msg.optionalSfixed64);
+
+    msg.optionalSfixed64 = -123;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 12);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(-123, newMsg.optionalSfixed64);
+  }
+
+  public void testNanoOptionalFloat() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalFloat = 123f;
+    assertTrue(123.0f == msg.optionalFloat);
+    msg.clear()
+       .optionalFloat = 456.0f;
+    assertTrue(456.0f == msg.optionalFloat);
+    msg.clear();
+    assertTrue(0.0f == msg.optionalFloat);
+
+    msg.optionalFloat = -123.456f;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 8);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(-123.456f == newMsg.optionalFloat);
+  }
+
+  public void testNanoOptionalDouble() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalDouble = 123;
+    assertTrue(123.0 == msg.optionalDouble);
+    msg.clear()
+       .optionalDouble = 456.0;
+    assertTrue(456.0 == msg.optionalDouble);
+    msg.clear();
+    assertTrue(0.0 == msg.optionalDouble);
+
+    msg.optionalDouble = -123.456;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 12);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(-123.456 == newMsg.optionalDouble);
+  }
+
+  public void testNanoOptionalBool() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalBool = true;
+    assertTrue(msg.optionalBool);
+    msg.clear()
+       .optionalBool = true;
+    assertTrue(msg.optionalBool);
+    msg.clear();
+    assertFalse(msg.optionalBool);
+
+    msg.optionalBool = true;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 5);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(newMsg.optionalBool);
+  }
+
+  public void testNanoOptionalString() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalString = "hello";
+    assertEquals("hello", msg.optionalString);
+    msg.clear();
+    assertTrue(msg.optionalString.isEmpty());
+    msg.clear()
+       .optionalString = "hello2";
+    assertEquals("hello2", msg.optionalString);
+    msg.clear();
+    assertTrue(msg.optionalString.isEmpty());
+
+    msg.optionalString = "bye";
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 8);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(newMsg.optionalString != null);
+    assertEquals("bye", newMsg.optionalString);
+  }
+
+  public void testNanoOptionalBytes() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertFalse(msg.optionalBytes.length > 0);
+    msg.optionalBytes = InternalNano.copyFromUtf8("hello");
+    assertTrue(msg.optionalBytes.length > 0);
+    assertEquals("hello", new String(msg.optionalBytes, "UTF-8"));
+    msg.clear();
+    assertFalse(msg.optionalBytes.length > 0);
+    msg.clear()
+       .optionalBytes = InternalNano.copyFromUtf8("hello");
+    assertTrue(msg.optionalBytes.length > 0);
+    msg.clear();
+    assertFalse(msg.optionalBytes.length > 0);
+
+    msg.optionalBytes = InternalNano.copyFromUtf8("bye");
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 8);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(newMsg.optionalBytes.length > 0);
+    assertEquals("bye", new String(newMsg.optionalBytes, "UTF-8"));
+  }
+
+  public void testNanoOptionalGroup() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    TestAllTypesNano.OptionalGroup grp = new TestAllTypesNano.OptionalGroup();
+    grp.a = 1;
+    assertFalse(msg.optionalGroup != null);
+    msg.optionalGroup = grp;
+    assertTrue(msg.optionalGroup != null);
+    assertEquals(1, msg.optionalGroup.a);
+    msg.clear();
+    assertFalse(msg.optionalGroup != null);
+    msg.clear()
+       .optionalGroup = new TestAllTypesNano.OptionalGroup();
+    msg.optionalGroup.a = 2;
+    assertTrue(msg.optionalGroup != null);
+    msg.clear();
+    assertFalse(msg.optionalGroup != null);
+
+    msg.optionalGroup = grp;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 10);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(newMsg.optionalGroup != null);
+    assertEquals(1, newMsg.optionalGroup.a);
+  }
+
+  public void testNanoOptionalGroupWithUnknownFieldsEnabled() throws Exception {
+    MessageWithGroup msg = new MessageWithGroup();
+    MessageWithGroup.Group grp = new MessageWithGroup.Group();
+    grp.a = 1;
+    msg.group = grp;
+    byte [] serialized = MessageNano.toByteArray(msg);
+
+    MessageWithGroup parsed = MessageWithGroup.parseFrom(serialized);
+    assertEquals(1, parsed.group.a);
+
+    byte [] serialized2 = MessageNano.toByteArray(parsed);
+    assertEquals(serialized.length, serialized2.length);
+    MessageWithGroup parsed2 = MessageWithGroup.parseFrom(serialized2);
+    assertEquals(1, parsed2.group.a);
+  }
+
+  public void testNanoOptionalNestedMessage() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    TestAllTypesNano.NestedMessage nestedMsg = new TestAllTypesNano.NestedMessage();
+    nestedMsg.bb = 1;
+    assertFalse(msg.optionalNestedMessage != null);
+    msg.optionalNestedMessage = nestedMsg;
+    assertTrue(msg.optionalNestedMessage != null);
+    assertEquals(1, msg.optionalNestedMessage.bb);
+    msg.clear();
+    assertFalse(msg.optionalNestedMessage != null);
+    msg.clear()
+       .optionalNestedMessage = new TestAllTypesNano.NestedMessage();
+    msg.optionalNestedMessage.bb = 2;
+    assertTrue(msg.optionalNestedMessage != null);
+    msg.clear();
+    assertFalse(msg.optionalNestedMessage != null);
+
+    msg.optionalNestedMessage = nestedMsg;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 8);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(newMsg.optionalNestedMessage != null);
+    assertEquals(1, newMsg.optionalNestedMessage.bb);
+  }
+
+  public void testNanoOptionalForeignMessage() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    NanoOuterClass.ForeignMessageNano nestedMsg = new NanoOuterClass.ForeignMessageNano();
+    nestedMsg.c = 1;
+    assertFalse(msg.optionalForeignMessage != null);
+    msg.optionalForeignMessage = nestedMsg;
+    assertTrue(msg.optionalForeignMessage != null);
+    assertEquals(1, msg.optionalForeignMessage.c);
+    msg.clear();
+    assertFalse(msg.optionalForeignMessage != null);
+    msg.clear()
+       .optionalForeignMessage = new NanoOuterClass.ForeignMessageNano();
+    msg.optionalForeignMessage.c = 2;
+    assertTrue(msg.optionalForeignMessage != null);
+    msg.clear();
+    assertFalse(msg.optionalForeignMessage != null);
+
+    msg.optionalForeignMessage = nestedMsg;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 8);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(newMsg.optionalForeignMessage != null);
+    assertEquals(1, newMsg.optionalForeignMessage.c);
+  }
+
+  public void testNanoOptionalImportMessage() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    UnittestImportNano.ImportMessageNano nestedMsg = new UnittestImportNano.ImportMessageNano();
+    nestedMsg.d = 1;
+    assertFalse(msg.optionalImportMessage != null);
+    msg.optionalImportMessage = nestedMsg;
+    assertTrue(msg.optionalImportMessage != null);
+    assertEquals(1, msg.optionalImportMessage.d);
+    msg.clear();
+    assertFalse(msg.optionalImportMessage != null);
+    msg.clear()
+       .optionalImportMessage = new UnittestImportNano.ImportMessageNano();
+    msg.optionalImportMessage.d = 2;
+    assertTrue(msg.optionalImportMessage != null);
+    msg.clear();
+    assertFalse(msg.optionalImportMessage != null);
+
+    msg.optionalImportMessage = nestedMsg;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 8);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(newMsg.optionalImportMessage != null);
+    assertEquals(1, newMsg.optionalImportMessage.d);
+  }
+
+  public void testNanoOptionalNestedEnum() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalNestedEnum = TestAllTypesNano.BAR;
+    assertEquals(TestAllTypesNano.BAR, msg.optionalNestedEnum);
+    msg.clear()
+       .optionalNestedEnum = TestAllTypesNano.BAZ;
+    assertEquals(TestAllTypesNano.BAZ, msg.optionalNestedEnum);
+    msg.clear();
+    assertEquals(TestAllTypesNano.FOO, msg.optionalNestedEnum);
+
+    msg.optionalNestedEnum = TestAllTypesNano.BAR;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(TestAllTypesNano.BAR, newMsg.optionalNestedEnum);
+  }
+
+  public void testNanoOptionalForeignEnum() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalForeignEnum = NanoOuterClass.FOREIGN_NANO_BAR;
+    assertEquals(NanoOuterClass.FOREIGN_NANO_BAR, msg.optionalForeignEnum);
+    msg.clear()
+       .optionalForeignEnum = NanoOuterClass.FOREIGN_NANO_BAZ;
+    assertEquals(NanoOuterClass.FOREIGN_NANO_BAZ, msg.optionalForeignEnum);
+    msg.clear();
+    assertEquals(NanoOuterClass.FOREIGN_NANO_FOO, msg.optionalForeignEnum);
+
+    msg.optionalForeignEnum = NanoOuterClass.FOREIGN_NANO_BAR;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(NanoOuterClass.FOREIGN_NANO_BAR, newMsg.optionalForeignEnum);
+  }
+
+  public void testNanoOptionalImportEnum() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalImportEnum = UnittestImportNano.IMPORT_NANO_BAR;
+    assertEquals(UnittestImportNano.IMPORT_NANO_BAR, msg.optionalImportEnum);
+    msg.clear()
+       .optionalImportEnum = UnittestImportNano.IMPORT_NANO_BAZ;
+    assertEquals(UnittestImportNano.IMPORT_NANO_BAZ, msg.optionalImportEnum);
+    msg.clear();
+    assertEquals(UnittestImportNano.IMPORT_NANO_FOO, msg.optionalImportEnum);
+
+    msg.optionalImportEnum = UnittestImportNano.IMPORT_NANO_BAR;
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(UnittestImportNano.IMPORT_NANO_BAR, newMsg.optionalImportEnum);
+  }
+
+  public void testNanoOptionalStringPiece() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalStringPiece = "hello";
+    assertEquals("hello", msg.optionalStringPiece);
+    msg.clear();
+    assertTrue(msg.optionalStringPiece.isEmpty());
+    msg.clear()
+       .optionalStringPiece = "hello2";
+    assertEquals("hello2", msg.optionalStringPiece);
+    msg.clear();
+    assertTrue(msg.optionalStringPiece.isEmpty());
+
+    msg.optionalStringPiece = "bye";
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(newMsg.optionalStringPiece != null);
+    assertEquals("bye", newMsg.optionalStringPiece);
+  }
+
+  public void testNanoOptionalCord() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalCord = "hello";
+    assertEquals("hello", msg.optionalCord);
+    msg.clear();
+    assertTrue(msg.optionalCord.isEmpty());
+    msg.clear()
+       .optionalCord = "hello2";
+    assertEquals("hello2", msg.optionalCord);
+    msg.clear();
+    assertTrue(msg.optionalCord.isEmpty());
+
+    msg.optionalCord = "bye";
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertTrue(newMsg.optionalCord != null);
+    assertEquals("bye", newMsg.optionalCord);
+  }
+
+  public void testNanoRepeatedInt32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedInt32.length);
+    msg.repeatedInt32 = new int[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedInt32[1]);
+    assertEquals(456, msg.repeatedInt32[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedInt32.length);
+    msg.clear()
+       .repeatedInt32 = new int[] { 456 };
+    assertEquals(1, msg.repeatedInt32.length);
+    assertEquals(456, msg.repeatedInt32[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedInt32.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedInt32 = new int[] { 123 };
+    assertEquals(1, msg.repeatedInt32.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedInt32.length);
+    assertEquals(123, newMsg.repeatedInt32[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedInt32 = new int[] { 123, 456 };
+    assertEquals(2, msg.repeatedInt32.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 10);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedInt32.length);
+    assertEquals(123, newMsg.repeatedInt32[0]);
+    assertEquals(456, newMsg.repeatedInt32[1]);
+  }
+
+  public void testNanoRepeatedInt64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedInt64.length);
+    msg.repeatedInt64 = new long[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedInt64[1]);
+    assertEquals(456, msg.repeatedInt64[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedInt64.length);
+    msg.clear()
+       .repeatedInt64 = new long[] { 456 };
+    assertEquals(1, msg.repeatedInt64.length);
+    assertEquals(456, msg.repeatedInt64[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedInt64.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedInt64 = new long[] { 123 };
+    assertEquals(1, msg.repeatedInt64.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedInt64.length);
+    assertEquals(123, newMsg.repeatedInt64[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedInt64 = new long[] { 123, 456 };
+    assertEquals(2, msg.repeatedInt64.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 10);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedInt64.length);
+    assertEquals(123, newMsg.repeatedInt64[0]);
+    assertEquals(456, newMsg.repeatedInt64[1]);
+  }
+
+  public void testNanoRepeatedUint32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedUint32.length);
+    msg.repeatedUint32 = new int[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedUint32[1]);
+    assertEquals(456, msg.repeatedUint32[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedUint32.length);
+    msg.clear()
+       .repeatedUint32 = new int[] { 456 };
+    assertEquals(1, msg.repeatedUint32.length);
+    assertEquals(456, msg.repeatedUint32[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedUint32.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedUint32 = new int[] { 123 };
+    assertEquals(1, msg.repeatedUint32.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedUint32.length);
+    assertEquals(123, newMsg.repeatedUint32[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedUint32 = new int[] { 123, 456 };
+    assertEquals(2, msg.repeatedUint32.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 10);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedUint32.length);
+    assertEquals(123, newMsg.repeatedUint32[0]);
+    assertEquals(456, newMsg.repeatedUint32[1]);
+  }
+
+  public void testNanoRepeatedUint64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedUint64.length);
+    msg.repeatedUint64 = new long[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedUint64[1]);
+    assertEquals(456, msg.repeatedUint64[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedUint64.length);
+    msg.clear()
+       .repeatedUint64 = new long[] { 456 };
+    assertEquals(1, msg.repeatedUint64.length);
+    assertEquals(456, msg.repeatedUint64[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedUint64.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedUint64 = new long[] { 123 };
+    assertEquals(1, msg.repeatedUint64.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedUint64.length);
+    assertEquals(123, newMsg.repeatedUint64[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedUint64 = new long[] { 123, 456 };
+    assertEquals(2, msg.repeatedUint64.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 10);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedUint64.length);
+    assertEquals(123, newMsg.repeatedUint64[0]);
+    assertEquals(456, newMsg.repeatedUint64[1]);
+  }
+
+  public void testNanoRepeatedSint32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedSint32.length);
+    msg.repeatedSint32 = new int[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedSint32[1]);
+    assertEquals(456, msg.repeatedSint32[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedSint32.length);
+    msg.clear()
+       .repeatedSint32 = new int[] { 456 };
+    assertEquals(1, msg.repeatedSint32.length);
+    assertEquals(456, msg.repeatedSint32[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedSint32.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedSint32 = new int[] { 123 };
+    assertEquals(1, msg.repeatedSint32.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 7);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedSint32.length);
+    assertEquals(123, newMsg.repeatedSint32[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedSint32 = new int[] { 123, 456 };
+    assertEquals(2, msg.repeatedSint32.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 11);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedSint32.length);
+    assertEquals(123, newMsg.repeatedSint32[0]);
+    assertEquals(456, newMsg.repeatedSint32[1]);
+  }
+
+  public void testNanoRepeatedSint64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedSint64.length);
+    msg.repeatedSint64 = new long[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedSint64[1]);
+    assertEquals(456, msg.repeatedSint64[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedSint64.length);
+    msg.clear()
+       .repeatedSint64 = new long[] { 456 };
+    assertEquals(1, msg.repeatedSint64.length);
+    assertEquals(456, msg.repeatedSint64[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedSint64.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedSint64 = new long[] { 123 };
+    assertEquals(1, msg.repeatedSint64.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 7);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedSint64.length);
+    assertEquals(123, newMsg.repeatedSint64[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedSint64 = new long[] { 123, 456 };
+    assertEquals(2, msg.repeatedSint64.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 11);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedSint64.length);
+    assertEquals(123, newMsg.repeatedSint64[0]);
+    assertEquals(456, newMsg.repeatedSint64[1]);
+  }
+
+  public void testNanoRepeatedFixed32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedFixed32.length);
+    msg.repeatedFixed32 = new int[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedFixed32[1]);
+    assertEquals(456, msg.repeatedFixed32[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedFixed32.length);
+    msg.clear()
+       .repeatedFixed32 = new int[] { 456 };
+    assertEquals(1, msg.repeatedFixed32.length);
+    assertEquals(456, msg.repeatedFixed32[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedFixed32.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedFixed32 = new int[] { 123 };
+    assertEquals(1, msg.repeatedFixed32.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedFixed32.length);
+    assertEquals(123, newMsg.repeatedFixed32[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedFixed32 = new int[] { 123, 456 };
+    assertEquals(2, msg.repeatedFixed32.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 15);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedFixed32.length);
+    assertEquals(123, newMsg.repeatedFixed32[0]);
+    assertEquals(456, newMsg.repeatedFixed32[1]);
+  }
+
+  public void testNanoRepeatedFixed64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedFixed64.length);
+    msg.repeatedFixed64 = new long[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedFixed64[1]);
+    assertEquals(456, msg.repeatedFixed64[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedFixed64.length);
+    msg.clear()
+       .repeatedFixed64 = new long[] { 456 };
+    assertEquals(1, msg.repeatedFixed64.length);
+    assertEquals(456, msg.repeatedFixed64[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedFixed64.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedFixed64 = new long[] { 123 };
+    assertEquals(1, msg.repeatedFixed64.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 13);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedFixed64.length);
+    assertEquals(123, newMsg.repeatedFixed64[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedFixed64 = new long[] { 123, 456 };
+    assertEquals(2, msg.repeatedFixed64.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 23);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedFixed64.length);
+    assertEquals(123, newMsg.repeatedFixed64[0]);
+    assertEquals(456, newMsg.repeatedFixed64[1]);
+  }
+
+  public void testNanoRepeatedSfixed32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedSfixed32.length);
+    msg.repeatedSfixed32 = new int[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedSfixed32[1]);
+    assertEquals(456, msg.repeatedSfixed32[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedSfixed32.length);
+    msg.clear()
+       .repeatedSfixed32 = new int[] { 456 };
+    assertEquals(1, msg.repeatedSfixed32.length);
+    assertEquals(456, msg.repeatedSfixed32[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedSfixed32.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedSfixed32 = new int[] { 123 };
+    assertEquals(1, msg.repeatedSfixed32.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedSfixed32.length);
+    assertEquals(123, newMsg.repeatedSfixed32[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedSfixed32 = new int[] { 123, 456 };
+    assertEquals(2, msg.repeatedSfixed32.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 15);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedSfixed32.length);
+    assertEquals(123, newMsg.repeatedSfixed32[0]);
+    assertEquals(456, newMsg.repeatedSfixed32[1]);
+  }
+
+  public void testNanoRepeatedSfixed64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedSfixed64.length);
+    msg.repeatedSfixed64 = new long[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedSfixed64[1]);
+    assertEquals(456, msg.repeatedSfixed64[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedSfixed64.length);
+    msg.clear()
+       .repeatedSfixed64 = new long[] { 456 };
+    assertEquals(1, msg.repeatedSfixed64.length);
+    assertEquals(456, msg.repeatedSfixed64[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedSfixed64.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedSfixed64 = new long[] { 123 };
+    assertEquals(1, msg.repeatedSfixed64.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 13);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedSfixed64.length);
+    assertEquals(123, newMsg.repeatedSfixed64[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedSfixed64 = new long[] { 123, 456 };
+    assertEquals(2, msg.repeatedSfixed64.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 23);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedSfixed64.length);
+    assertEquals(123, newMsg.repeatedSfixed64[0]);
+    assertEquals(456, newMsg.repeatedSfixed64[1]);
+  }
+
+  public void testNanoRepeatedFloat() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedFloat.length);
+    msg.repeatedFloat = new float[] { 123f, 789f, 456f };
+    assertEquals(789f, msg.repeatedFloat[1]);
+    assertEquals(456f, msg.repeatedFloat[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedFloat.length);
+    msg.clear()
+       .repeatedFloat = new float[] { 456f };
+    assertEquals(1, msg.repeatedFloat.length);
+    assertEquals(456f, msg.repeatedFloat[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedFloat.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedFloat = new float[] { 123f };
+    assertEquals(1, msg.repeatedFloat.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedFloat.length);
+    assertEquals(123f, newMsg.repeatedFloat[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedFloat = new float[] { 123f, 456f };
+    assertEquals(2, msg.repeatedFloat.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 15);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedFloat.length);
+    assertEquals(123f, newMsg.repeatedFloat[0]);
+    assertEquals(456f, newMsg.repeatedFloat[1]);
+  }
+
+  public void testNanoRepeatedDouble() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedDouble.length);
+    msg.repeatedDouble = new double[] { 123.0, 789.0, 456.0 };
+    assertEquals(789.0, msg.repeatedDouble[1]);
+    assertEquals(456.0, msg.repeatedDouble[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedDouble.length);
+    msg.clear()
+       .repeatedDouble = new double[] { 456.0 };
+    assertEquals(1, msg.repeatedDouble.length);
+    assertEquals(456.0, msg.repeatedDouble[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedDouble.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedDouble = new double[] { 123.0 };
+    assertEquals(1, msg.repeatedDouble.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 13);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedDouble.length);
+    assertEquals(123.0, newMsg.repeatedDouble[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedDouble = new double[] { 123.0, 456.0 };
+    assertEquals(2, msg.repeatedDouble.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 23);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedDouble.length);
+    assertEquals(123.0, newMsg.repeatedDouble[0]);
+    assertEquals(456.0, newMsg.repeatedDouble[1]);
+  }
+
+  public void testNanoRepeatedBool() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedBool.length);
+    msg.repeatedBool = new boolean[] { false, true, false };
+    assertTrue(msg.repeatedBool[1]);
+    assertFalse(msg.repeatedBool[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedBool.length);
+    msg.clear()
+       .repeatedBool = new boolean[] { true };
+    assertEquals(1, msg.repeatedBool.length);
+    assertTrue(msg.repeatedBool[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedBool.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedBool = new boolean[] { false };
+    assertEquals(1, msg.repeatedBool.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedBool.length);
+    assertFalse(newMsg.repeatedBool[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedBool = new boolean[] { true, false };
+    assertEquals(2, msg.repeatedBool.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedBool.length);
+    assertTrue(newMsg.repeatedBool[0]);
+    assertFalse(newMsg.repeatedBool[1]);
+  }
+
+  public void testNanoRepeatedString() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedString.length);
+    msg.repeatedString = new String[] { "hello", "bye", "boo" };
+    assertEquals("bye", msg.repeatedString[1]);
+    assertEquals("boo", msg.repeatedString[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedString.length);
+    msg.clear()
+       .repeatedString = new String[] { "boo" };
+    assertEquals(1, msg.repeatedString.length);
+    assertEquals("boo", msg.repeatedString[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedString.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedString = new String[] { "" };
+    assertEquals(1, msg.repeatedString.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedString.length);
+    assertTrue(newMsg.repeatedString[0].isEmpty());
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedString = new String[] { "hello", "world" };
+    assertEquals(2, msg.repeatedString.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 19);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedString.length);
+    assertEquals("hello", newMsg.repeatedString[0]);
+    assertEquals("world", newMsg.repeatedString[1]);
+  }
+
+  public void testNanoRepeatedBytes() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedBytes.length);
+    msg.repeatedBytes = new byte[][] {
+        InternalNano.copyFromUtf8("hello"),
+        InternalNano.copyFromUtf8("bye"),
+        InternalNano.copyFromUtf8("boo")
+    };
+    assertEquals("bye", new String(msg.repeatedBytes[1], "UTF-8"));
+    assertEquals("boo", new String(msg.repeatedBytes[2], "UTF-8"));
+    msg.clear();
+    assertEquals(0, msg.repeatedBytes.length);
+    msg.clear()
+       .repeatedBytes = new byte[][] { InternalNano.copyFromUtf8("boo") };
+    assertEquals(1, msg.repeatedBytes.length);
+    assertEquals("boo", new String(msg.repeatedBytes[0], "UTF-8"));
+    msg.clear();
+    assertEquals(0, msg.repeatedBytes.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedBytes = new byte[][] { InternalNano.copyFromUtf8("") };
+    assertEquals(1, msg.repeatedBytes.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedBytes.length);
+    assertTrue(newMsg.repeatedBytes[0].length == 0);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedBytes = new byte[][] {
+      InternalNano.copyFromUtf8("hello"),
+      InternalNano.copyFromUtf8("world")
+    };
+    assertEquals(2, msg.repeatedBytes.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 19);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedBytes.length);
+    assertEquals("hello", new String(newMsg.repeatedBytes[0], "UTF-8"));
+    assertEquals("world", new String(newMsg.repeatedBytes[1], "UTF-8"));
+  }
+
+  public void testNanoRepeatedGroup() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    TestAllTypesNano.RepeatedGroup group0 =
+      new TestAllTypesNano.RepeatedGroup();
+    group0.a = 0;
+    TestAllTypesNano.RepeatedGroup group1 =
+      new TestAllTypesNano.RepeatedGroup();
+    group1.a = 1;
+    TestAllTypesNano.RepeatedGroup group2 =
+      new TestAllTypesNano.RepeatedGroup();
+    group2.a = 2;
+
+    msg.repeatedGroup = new TestAllTypesNano.RepeatedGroup[] { group0, group1, group2 };
+    assertEquals(3, msg.repeatedGroup.length);
+    assertEquals(0, msg.repeatedGroup[0].a);
+    assertEquals(1, msg.repeatedGroup[1].a);
+    assertEquals(2, msg.repeatedGroup[2].a);
+    msg.clear();
+    assertEquals(0, msg.repeatedGroup.length);
+    msg.clear()
+       .repeatedGroup = new TestAllTypesNano.RepeatedGroup[] { group1 };
+    assertEquals(1, msg.repeatedGroup.length);
+    assertEquals(1, msg.repeatedGroup[0].a);
+    msg.clear();
+    assertEquals(0, msg.repeatedGroup.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedGroup = new TestAllTypesNano.RepeatedGroup[] { group0 };
+    assertEquals(1, msg.repeatedGroup.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 7);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedGroup.length);
+    assertEquals(0, newMsg.repeatedGroup[0].a);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedGroup = new TestAllTypesNano.RepeatedGroup[] { group0, group1 };
+    assertEquals(2, msg.repeatedGroup.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 14);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedGroup.length);
+    assertEquals(0, newMsg.repeatedGroup[0].a);
+    assertEquals(1, newMsg.repeatedGroup[1].a);
+  }
+
+  public void testNanoRepeatedNestedMessage() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    TestAllTypesNano.NestedMessage nestedMsg0 =
+      new TestAllTypesNano.NestedMessage();
+    nestedMsg0.bb = 0;
+    TestAllTypesNano.NestedMessage nestedMsg1 =
+      new TestAllTypesNano.NestedMessage();
+    nestedMsg1.bb = 1;
+    TestAllTypesNano.NestedMessage nestedMsg2 =
+      new TestAllTypesNano.NestedMessage();
+    nestedMsg2.bb = 2;
+
+    msg.repeatedNestedMessage =
+        new TestAllTypesNano.NestedMessage[] { nestedMsg0, nestedMsg1, nestedMsg2 };
+    assertEquals(3, msg.repeatedNestedMessage.length);
+    assertEquals(0, msg.repeatedNestedMessage[0].bb);
+    assertEquals(1, msg.repeatedNestedMessage[1].bb);
+    assertEquals(2, msg.repeatedNestedMessage[2].bb);
+    msg.clear();
+    assertEquals(0, msg.repeatedNestedMessage.length);
+    msg.clear()
+       .repeatedNestedMessage = new TestAllTypesNano.NestedMessage[] { nestedMsg1 };
+    assertEquals(1, msg.repeatedNestedMessage.length);
+    assertEquals(1, msg.repeatedNestedMessage[0].bb);
+    msg.clear();
+    assertEquals(0, msg.repeatedNestedMessage.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedNestedMessage = new TestAllTypesNano.NestedMessage[] { nestedMsg0 };
+    assertEquals(1, msg.repeatedNestedMessage.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedNestedMessage.length);
+    assertEquals(0, newMsg.repeatedNestedMessage[0].bb);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedNestedMessage = new TestAllTypesNano.NestedMessage[] { nestedMsg0, nestedMsg1 };
+    assertEquals(2, msg.repeatedNestedMessage.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 11);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedNestedMessage.length);
+    assertEquals(0, newMsg.repeatedNestedMessage[0].bb);
+    assertEquals(1, newMsg.repeatedNestedMessage[1].bb);
+  }
+
+  public void testNanoRepeatedForeignMessage() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    NanoOuterClass.ForeignMessageNano foreignMsg0 =
+      new NanoOuterClass.ForeignMessageNano();
+    foreignMsg0.c = 0;
+    NanoOuterClass.ForeignMessageNano foreignMsg1 =
+      new NanoOuterClass.ForeignMessageNano();
+    foreignMsg1.c = 1;
+    NanoOuterClass.ForeignMessageNano foreignMsg2 =
+      new NanoOuterClass.ForeignMessageNano();
+    foreignMsg2.c = 2;
+
+    msg.repeatedForeignMessage =
+        new NanoOuterClass.ForeignMessageNano[] { foreignMsg0, foreignMsg1, foreignMsg2 };
+    assertEquals(3, msg.repeatedForeignMessage.length);
+    assertEquals(0, msg.repeatedForeignMessage[0].c);
+    assertEquals(1, msg.repeatedForeignMessage[1].c);
+    assertEquals(2, msg.repeatedForeignMessage[2].c);
+    msg.clear();
+    assertEquals(0, msg.repeatedForeignMessage.length);
+    msg.clear()
+       .repeatedForeignMessage = new NanoOuterClass.ForeignMessageNano[] { foreignMsg1 };
+    assertEquals(1, msg.repeatedForeignMessage.length);
+    assertEquals(1, msg.repeatedForeignMessage[0].c);
+    msg.clear();
+    assertEquals(0, msg.repeatedForeignMessage.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedForeignMessage = new NanoOuterClass.ForeignMessageNano[] { foreignMsg0 };
+    assertEquals(1, msg.repeatedForeignMessage.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedForeignMessage.length);
+    assertEquals(0, newMsg.repeatedForeignMessage[0].c);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedForeignMessage = new NanoOuterClass.ForeignMessageNano[] { foreignMsg0, foreignMsg1 };
+    assertEquals(2, msg.repeatedForeignMessage.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 11);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedForeignMessage.length);
+    assertEquals(0, newMsg.repeatedForeignMessage[0].c);
+    assertEquals(1, newMsg.repeatedForeignMessage[1].c);
+  }
+
+  public void testNanoRepeatedImportMessage() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    UnittestImportNano.ImportMessageNano foreignMsg0 =
+      new UnittestImportNano.ImportMessageNano();
+    foreignMsg0.d = 0;
+    UnittestImportNano.ImportMessageNano foreignMsg1 =
+      new UnittestImportNano.ImportMessageNano();
+    foreignMsg1.d = 1;
+    UnittestImportNano.ImportMessageNano foreignMsg2 =
+      new UnittestImportNano.ImportMessageNano();
+    foreignMsg2.d = 2;
+
+    msg.repeatedImportMessage =
+        new UnittestImportNano.ImportMessageNano[] { foreignMsg0, foreignMsg1, foreignMsg2 };
+    assertEquals(3, msg.repeatedImportMessage.length);
+    assertEquals(0, msg.repeatedImportMessage[0].d);
+    assertEquals(1, msg.repeatedImportMessage[1].d);
+    assertEquals(2, msg.repeatedImportMessage[2].d);
+    msg.clear();
+    assertEquals(0, msg.repeatedImportMessage.length);
+    msg.clear()
+       .repeatedImportMessage = new UnittestImportNano.ImportMessageNano[] { foreignMsg1 };
+    assertEquals(1, msg.repeatedImportMessage.length);
+    assertEquals(1, msg.repeatedImportMessage[0].d);
+    msg.clear();
+    assertEquals(0, msg.repeatedImportMessage.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedImportMessage = new UnittestImportNano.ImportMessageNano[] { foreignMsg0 };
+    assertEquals(1, msg.repeatedImportMessage.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedImportMessage.length);
+    assertEquals(0, newMsg.repeatedImportMessage[0].d);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedImportMessage = new UnittestImportNano.ImportMessageNano[] { foreignMsg0, foreignMsg1 };
+    assertEquals(2, msg.repeatedImportMessage.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 11);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedImportMessage.length);
+    assertEquals(0, newMsg.repeatedImportMessage[0].d);
+    assertEquals(1, newMsg.repeatedImportMessage[1].d);
+  }
+
+  public void testNanoRepeatedNestedEnum() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.repeatedNestedEnum = new int[] {
+        TestAllTypesNano.FOO,
+        TestAllTypesNano.BAR,
+        TestAllTypesNano.BAZ
+    };
+    assertEquals(3, msg.repeatedNestedEnum.length);
+    assertEquals(TestAllTypesNano.FOO, msg.repeatedNestedEnum[0]);
+    assertEquals(TestAllTypesNano.BAR, msg.repeatedNestedEnum[1]);
+    assertEquals(TestAllTypesNano.BAZ, msg.repeatedNestedEnum[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedNestedEnum.length);
+    msg.clear()
+       .repeatedNestedEnum = new int[] { TestAllTypesNano.BAR };
+    assertEquals(1, msg.repeatedNestedEnum.length);
+    assertEquals(TestAllTypesNano.BAR, msg.repeatedNestedEnum[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedNestedEnum.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedNestedEnum = new int[] { TestAllTypesNano.FOO };
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedNestedEnum.length);
+    assertEquals(TestAllTypesNano.FOO, msg.repeatedNestedEnum[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedNestedEnum = new int[] { TestAllTypesNano.FOO, TestAllTypesNano.BAR };
+    assertEquals(2, msg.repeatedNestedEnum.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedNestedEnum.length);
+    assertEquals(TestAllTypesNano.FOO, msg.repeatedNestedEnum[0]);
+    assertEquals(TestAllTypesNano.BAR, msg.repeatedNestedEnum[1]);
+  }
+
+  public void testNanoRepeatedForeignEnum() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.repeatedForeignEnum = new int[] {
+        NanoOuterClass.FOREIGN_NANO_FOO,
+        NanoOuterClass.FOREIGN_NANO_BAR,
+        NanoOuterClass.FOREIGN_NANO_BAZ
+    };
+    assertEquals(3, msg.repeatedForeignEnum.length);
+    assertEquals(NanoOuterClass.FOREIGN_NANO_FOO, msg.repeatedForeignEnum[0]);
+    assertEquals(NanoOuterClass.FOREIGN_NANO_BAR, msg.repeatedForeignEnum[1]);
+    assertEquals(NanoOuterClass.FOREIGN_NANO_BAZ, msg.repeatedForeignEnum[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedForeignEnum.length);
+    msg.clear()
+       .repeatedForeignEnum = new int[] { NanoOuterClass.FOREIGN_NANO_BAR };
+    assertEquals(1, msg.repeatedForeignEnum.length);
+    assertEquals(NanoOuterClass.FOREIGN_NANO_BAR, msg.repeatedForeignEnum[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedForeignEnum.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedForeignEnum = new int[] { NanoOuterClass.FOREIGN_NANO_FOO };
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedForeignEnum.length);
+    assertEquals(NanoOuterClass.FOREIGN_NANO_FOO, msg.repeatedForeignEnum[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedForeignEnum = new int[] {
+      NanoOuterClass.FOREIGN_NANO_FOO,
+      NanoOuterClass.FOREIGN_NANO_BAR
+    };
+    assertEquals(2, msg.repeatedForeignEnum.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedForeignEnum.length);
+    assertEquals(NanoOuterClass.FOREIGN_NANO_FOO, msg.repeatedForeignEnum[0]);
+    assertEquals(NanoOuterClass.FOREIGN_NANO_BAR, msg.repeatedForeignEnum[1]);
+  }
+
+  public void testNanoRepeatedImportEnum() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.repeatedImportEnum = new int[] {
+        UnittestImportNano.IMPORT_NANO_FOO,
+        UnittestImportNano.IMPORT_NANO_BAR,
+        UnittestImportNano.IMPORT_NANO_BAZ
+    };
+    assertEquals(3, msg.repeatedImportEnum.length);
+    assertEquals(UnittestImportNano.IMPORT_NANO_FOO, msg.repeatedImportEnum[0]);
+    assertEquals(UnittestImportNano.IMPORT_NANO_BAR, msg.repeatedImportEnum[1]);
+    assertEquals(UnittestImportNano.IMPORT_NANO_BAZ, msg.repeatedImportEnum[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedImportEnum.length);
+    msg.clear()
+       .repeatedImportEnum = new int[] { UnittestImportNano.IMPORT_NANO_BAR };
+    assertEquals(1, msg.repeatedImportEnum.length);
+    assertEquals(UnittestImportNano.IMPORT_NANO_BAR, msg.repeatedImportEnum[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedImportEnum.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedImportEnum = new int[] { UnittestImportNano.IMPORT_NANO_FOO };
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedImportEnum.length);
+    assertEquals(UnittestImportNano.IMPORT_NANO_FOO, msg.repeatedImportEnum[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedImportEnum = new int[] {
+      UnittestImportNano.IMPORT_NANO_FOO,
+      UnittestImportNano.IMPORT_NANO_BAR
+    };
+    assertEquals(2, msg.repeatedImportEnum.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedImportEnum.length);
+    assertEquals(UnittestImportNano.IMPORT_NANO_FOO, msg.repeatedImportEnum[0]);
+    assertEquals(UnittestImportNano.IMPORT_NANO_BAR, msg.repeatedImportEnum[1]);
+  }
+
+  public void testNanoRepeatedStringPiece() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedStringPiece.length);
+    msg.repeatedStringPiece = new String[] { "hello", "bye", "boo" };
+    assertEquals("bye", msg.repeatedStringPiece[1]);
+    assertEquals("boo", msg.repeatedStringPiece[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedStringPiece.length);
+    msg.clear()
+       .repeatedStringPiece = new String[] { "boo" };
+    assertEquals(1, msg.repeatedStringPiece.length);
+    assertEquals("boo", msg.repeatedStringPiece[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedStringPiece.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedStringPiece = new String[] { "" };
+    assertEquals(1, msg.repeatedStringPiece.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedStringPiece.length);
+    assertTrue(newMsg.repeatedStringPiece[0].isEmpty());
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedStringPiece = new String[] { "hello", "world" };
+    assertEquals(2, msg.repeatedStringPiece.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 19);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedStringPiece.length);
+    assertEquals("hello", newMsg.repeatedStringPiece[0]);
+    assertEquals("world", newMsg.repeatedStringPiece[1]);
+  }
+
+  public void testNanoRepeatedCord() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedCord.length);
+    msg.repeatedCord = new String[] { "hello", "bye", "boo" };
+    assertEquals("bye", msg.repeatedCord[1]);
+    assertEquals("boo", msg.repeatedCord[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedCord.length);
+    msg.clear()
+       .repeatedCord = new String[] { "boo" };
+    assertEquals(1, msg.repeatedCord.length);
+    assertEquals("boo", msg.repeatedCord[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedCord.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedCord = new String[] { "" };
+    assertEquals(1, msg.repeatedCord.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 6);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedCord.length);
+    assertTrue(newMsg.repeatedCord[0].isEmpty());
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedCord = new String[] { "hello", "world" };
+    assertEquals(2, msg.repeatedCord.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 19);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedCord.length);
+    assertEquals("hello", newMsg.repeatedCord[0]);
+    assertEquals("world", newMsg.repeatedCord[1]);
+  }
+
+  public void testNanoRepeatedPackedInt32() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedPackedInt32.length);
+    msg.repeatedPackedInt32 = new int[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedPackedInt32[1]);
+    assertEquals(456, msg.repeatedPackedInt32[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedPackedInt32.length);
+    msg.clear()
+       .repeatedPackedInt32 = new int[] { 456 };
+    assertEquals(1, msg.repeatedPackedInt32.length);
+    assertEquals(456, msg.repeatedPackedInt32[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedPackedInt32.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedPackedInt32 = new int[] { 123 };
+    assertEquals(1, msg.repeatedPackedInt32.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 7);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedPackedInt32.length);
+    assertEquals(123, newMsg.repeatedPackedInt32[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedPackedInt32 = new int[] { 123, 456 };
+    assertEquals(2, msg.repeatedPackedInt32.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 9);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedPackedInt32.length);
+    assertEquals(123, newMsg.repeatedPackedInt32[0]);
+    assertEquals(456, newMsg.repeatedPackedInt32[1]);
+  }
+
+  public void testNanoRepeatedPackedSfixed64() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    assertEquals(0, msg.repeatedPackedSfixed64.length);
+    msg.repeatedPackedSfixed64 = new long[] { 123, 789, 456 };
+    assertEquals(789, msg.repeatedPackedSfixed64[1]);
+    assertEquals(456, msg.repeatedPackedSfixed64[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedPackedSfixed64.length);
+    msg.clear()
+       .repeatedPackedSfixed64 = new long[] { 456 };
+    assertEquals(1, msg.repeatedPackedSfixed64.length);
+    assertEquals(456, msg.repeatedPackedSfixed64[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedPackedSfixed64.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedPackedSfixed64 = new long[] { 123 };
+    assertEquals(1, msg.repeatedPackedSfixed64.length);
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 14);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedPackedSfixed64.length);
+    assertEquals(123, newMsg.repeatedPackedSfixed64[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedPackedSfixed64 = new long[] { 123, 456 };
+    assertEquals(2, msg.repeatedPackedSfixed64.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 22);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedPackedSfixed64.length);
+    assertEquals(123, newMsg.repeatedPackedSfixed64[0]);
+    assertEquals(456, newMsg.repeatedPackedSfixed64[1]);
+  }
+
+  public void testNanoRepeatedPackedNestedEnum() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.repeatedPackedNestedEnum = new int[] {
+        TestAllTypesNano.FOO,
+        TestAllTypesNano.BAR,
+        TestAllTypesNano.BAZ
+    };
+    assertEquals(3, msg.repeatedPackedNestedEnum.length);
+    assertEquals(TestAllTypesNano.FOO, msg.repeatedPackedNestedEnum[0]);
+    assertEquals(TestAllTypesNano.BAR, msg.repeatedPackedNestedEnum[1]);
+    assertEquals(TestAllTypesNano.BAZ, msg.repeatedPackedNestedEnum[2]);
+    msg.clear();
+    assertEquals(0, msg.repeatedPackedNestedEnum.length);
+    msg.clear()
+       .repeatedPackedNestedEnum = new int[] { TestAllTypesNano.BAR };
+    assertEquals(1, msg.repeatedPackedNestedEnum.length);
+    assertEquals(TestAllTypesNano.BAR, msg.repeatedPackedNestedEnum[0]);
+    msg.clear();
+    assertEquals(0, msg.repeatedPackedNestedEnum.length);
+
+    // Test 1 entry
+    msg.clear()
+       .repeatedPackedNestedEnum = new int[] { TestAllTypesNano.FOO };
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 7);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(1, newMsg.repeatedPackedNestedEnum.length);
+    assertEquals(TestAllTypesNano.FOO, msg.repeatedPackedNestedEnum[0]);
+
+    // Test 2 entries
+    msg.clear()
+       .repeatedPackedNestedEnum = new int[] { TestAllTypesNano.FOO, TestAllTypesNano.BAR };
+    assertEquals(2, msg.repeatedPackedNestedEnum.length);
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 8);
+    assertEquals(result.length, msgSerializedSize);
+
+    newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(2, newMsg.repeatedPackedNestedEnum.length);
+    assertEquals(TestAllTypesNano.FOO, msg.repeatedPackedNestedEnum[0]);
+    assertEquals(TestAllTypesNano.BAR, msg.repeatedPackedNestedEnum[1]);
+  }
+
+  public void testNanoRepeatedPackedSerializedSize() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.repeatedPackedInt32 = new int[] { 123, 789, 456 };
+    int msgSerializedSize = msg.getSerializedSize();
+    byte [] result = MessageNano.toByteArray(msg);
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 11);
+    assertEquals(result.length, msgSerializedSize);
+    TestAllTypesNano msg2 = new TestAllTypesNano();
+    msg2.repeatedPackedInt32 = new int[] { 123, 789, 456 };
+    byte [] result2 = new byte[msgSerializedSize];
+    MessageNano.toByteArray(msg2, result2, 0, msgSerializedSize);
+
+    // Check equal size and content.
+    assertEquals(msgSerializedSize, msg2.getSerializedSize());
+    assertTrue(Arrays.equals(result, result2));
+  }
+
+  public void testNanoRepeatedInt32ReMerge() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.repeatedInt32 = new int[] { 234 };
+    byte [] result1 = MessageNano.toByteArray(msg);
+
+    msg.clear().optionalInt32 = 789;
+    byte [] result2 = MessageNano.toByteArray(msg);
+
+    msg.clear().repeatedInt32 = new int[] { 123, 456 };
+    byte [] result3 = MessageNano.toByteArray(msg);
+
+    // Concatenate the three serializations and read as one message.
+    byte [] result = new byte[result1.length + result2.length + result3.length];
+    System.arraycopy(result1, 0, result, 0, result1.length);
+    System.arraycopy(result2, 0, result, result1.length, result2.length);
+    System.arraycopy(result3, 0, result, result1.length + result2.length, result3.length);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(789, newMsg.optionalInt32);
+    assertEquals(3, newMsg.repeatedInt32.length);
+    assertEquals(234, newMsg.repeatedInt32[0]);
+    assertEquals(123, newMsg.repeatedInt32[1]);
+    assertEquals(456, newMsg.repeatedInt32[2]);
+  }
+
+  public void testNanoRepeatedNestedEnumReMerge() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.repeatedNestedEnum = new int[] { TestAllTypesNano.FOO };
+    byte [] result1 = MessageNano.toByteArray(msg);
+
+    msg.clear().optionalInt32 = 789;
+    byte [] result2 = MessageNano.toByteArray(msg);
+
+    msg.clear().repeatedNestedEnum = new int[] { TestAllTypesNano.BAR, TestAllTypesNano.FOO };
+    byte [] result3 = MessageNano.toByteArray(msg);
+
+    // Concatenate the three serializations and read as one message.
+    byte [] result = new byte[result1.length + result2.length + result3.length];
+    System.arraycopy(result1, 0, result, 0, result1.length);
+    System.arraycopy(result2, 0, result, result1.length, result2.length);
+    System.arraycopy(result3, 0, result, result1.length + result2.length, result3.length);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(789, newMsg.optionalInt32);
+    assertEquals(3, newMsg.repeatedNestedEnum.length);
+    assertEquals(TestAllTypesNano.FOO, newMsg.repeatedNestedEnum[0]);
+    assertEquals(TestAllTypesNano.BAR, newMsg.repeatedNestedEnum[1]);
+    assertEquals(TestAllTypesNano.FOO, newMsg.repeatedNestedEnum[2]);
+  }
+
+  public void testNanoRepeatedNestedMessageReMerge() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    TestAllTypesNano.NestedMessage nestedMsg0 =
+      new TestAllTypesNano.NestedMessage();
+    nestedMsg0.bb = 0;
+    TestAllTypesNano.NestedMessage nestedMsg1 =
+      new TestAllTypesNano.NestedMessage();
+    nestedMsg1.bb = 1;
+    TestAllTypesNano.NestedMessage nestedMsg2 =
+      new TestAllTypesNano.NestedMessage();
+    nestedMsg2.bb = 2;
+
+    msg.repeatedNestedMessage = new TestAllTypesNano.NestedMessage[] { nestedMsg0 };
+    byte [] result1 = MessageNano.toByteArray(msg);
+
+    msg.clear().optionalInt32 = 789;
+    byte [] result2 = MessageNano.toByteArray(msg);
+
+    msg.clear().repeatedNestedMessage =
+        new TestAllTypesNano.NestedMessage[] { nestedMsg1, nestedMsg2 };
+    byte [] result3 = MessageNano.toByteArray(msg);
+
+    // Concatenate the three serializations and read as one message.
+    byte [] result = new byte[result1.length + result2.length + result3.length];
+    System.arraycopy(result1, 0, result, 0, result1.length);
+    System.arraycopy(result2, 0, result, result1.length, result2.length);
+    System.arraycopy(result3, 0, result, result1.length + result2.length, result3.length);
+
+    TestAllTypesNano newMsg = TestAllTypesNano.parseFrom(result);
+    assertEquals(789, newMsg.optionalInt32);
+    assertEquals(3, newMsg.repeatedNestedMessage.length);
+    assertEquals(nestedMsg0.bb, newMsg.repeatedNestedMessage[0].bb);
+    assertEquals(nestedMsg1.bb, newMsg.repeatedNestedMessage[1].bb);
+    assertEquals(nestedMsg2.bb, newMsg.repeatedNestedMessage[2].bb);
+  }
+
+  /**
+   * Tests that invalid enum values from the wire are not accepted.
+   */
+  public void testNanoEnumValidity() throws Exception {
+    final int invalid = 120;
+    final int alsoInvalid = 121;
+
+    EnumValidity.M m = new EnumValidity.M();
+    // Sanity check & baseline of the assertions for the first case below.
+    assertEquals(EnumValidity.E.default_, m.optionalE);
+    assertEquals(EnumValidity.E.BAZ, m.defaultE);
+
+    m.optionalE = invalid;
+    m.defaultE = invalid;
+    // E contains all valid values
+    m.repeatedE = new int[] {EnumValidity.E.FOO, EnumValidity.E.BAR};
+    m.packedE = new int[] {EnumValidity.E.FOO, EnumValidity.E.BAZ};
+    // E2 contains some invalid values
+    m.repeatedE2 = new int[] {invalid, EnumValidity.E.BAR, alsoInvalid};
+    m.packedE2 = new int[] {EnumValidity.E.FOO, invalid, alsoInvalid};
+    // E3 contains all invalid values
+    m.repeatedE3 = new int[] {invalid, invalid};
+    m.packedE3 = new int[] {alsoInvalid, alsoInvalid};
+    byte[] serialized = MessageNano.toByteArray(m);
+    // Sanity check that we do have all data in the byte array.
+    assertEquals(31, serialized.length);
+
+    // Test 1: tests that invalid values aren't included in the deserialized message.
+    EnumValidity.M deserialized = MessageNano.mergeFrom(new EnumValidity.M(), serialized);
+    assertEquals(EnumValidity.E.default_, deserialized.optionalE);
+    assertEquals(EnumValidity.E.BAZ, deserialized.defaultE);
+    assertTrue(Arrays.equals(
+        new int[] {EnumValidity.E.FOO, EnumValidity.E.BAR}, deserialized.repeatedE));
+    assertTrue(Arrays.equals(
+        new int[] {EnumValidity.E.FOO, EnumValidity.E.BAZ}, deserialized.packedE));
+    assertTrue(Arrays.equals(
+        new int[] {EnumValidity.E.BAR}, deserialized.repeatedE2));
+    assertTrue(Arrays.equals(
+        new int[] {EnumValidity.E.FOO}, deserialized.packedE2));
+    assertEquals(0, deserialized.repeatedE3.length);
+    assertEquals(0, deserialized.packedE3.length);
+
+    // Test 2: tests that invalid values do not override previous values in the field, including
+    // arrays, including pre-existing invalid values.
+    deserialized.optionalE = EnumValidity.E.BAR;
+    deserialized.defaultE = alsoInvalid;
+    deserialized.repeatedE = new int[] {EnumValidity.E.BAZ};
+    deserialized.packedE = new int[] {EnumValidity.E.BAZ, alsoInvalid};
+    deserialized.repeatedE2 = new int[] {invalid, alsoInvalid};
+    deserialized.packedE2 = null;
+    deserialized.repeatedE3 = null;
+    deserialized.packedE3 = new int[0];
+    MessageNano.mergeFrom(deserialized, serialized);
+    assertEquals(EnumValidity.E.BAR, deserialized.optionalE);
+    assertEquals(alsoInvalid, deserialized.defaultE);
+    assertTrue(Arrays.equals(
+        new int[] {EnumValidity.E.BAZ, /* + */ EnumValidity.E.FOO, EnumValidity.E.BAR},
+        deserialized.repeatedE));
+    assertTrue(Arrays.equals(
+        new int[] {EnumValidity.E.BAZ, alsoInvalid, /* + */ EnumValidity.E.FOO, EnumValidity.E.BAZ},
+        deserialized.packedE));
+    assertTrue(Arrays.equals(
+        new int[] {invalid, alsoInvalid, /* + */ EnumValidity.E.BAR},
+        deserialized.repeatedE2));
+    assertTrue(Arrays.equals(
+        new int[] {/* <null> + */ EnumValidity.E.FOO},
+        deserialized.packedE2));
+    assertNull(deserialized.repeatedE3); // null + all invalid == null
+    assertEquals(0, deserialized.packedE3.length); // empty + all invalid == empty
+
+    // Test 3: reading by alternative forms
+    EnumValidity.Alt alt = MessageNano.mergeFrom(new EnumValidity.Alt(), serialized);
+    assertEquals(EnumValidity.E.BAR, // last valid value in m.repeatedE2
+        alt.repeatedE2AsOptional);
+    assertTrue(Arrays.equals(new int[] {EnumValidity.E.FOO}, alt.packedE2AsNonPacked));
+    assertEquals(0, alt.nonPackedE3AsPacked.length);
+  }
+
+  /**
+   * Tests the same as {@link #testNanoEnumValidity()} with accessor style. Repeated fields are
+   * not re-tested here because they are not affected by the accessor style.
+   */
+  public void testNanoEnumValidityAccessors() throws Exception {
+    final int invalid = 120;
+    final int alsoInvalid = 121;
+
+    EnumValidityAccessors.M m = new EnumValidityAccessors.M();
+    // Sanity check & baseline of the assertions for the first case below.
+    assertEquals(EnumValidityAccessors.default_, m.getOptionalE());
+    assertEquals(EnumValidityAccessors.BAZ, m.getDefaultE());
+
+    m.setOptionalE(invalid);
+    m.setDefaultE(invalid);
+    // Set repeatedE2 for Alt.repeatedE2AsOptional
+    m.repeatedE2 = new int[] {invalid, EnumValidityAccessors.BAR, alsoInvalid};
+    byte[] serialized = MessageNano.toByteArray(m);
+    // Sanity check that we do have all data in the byte array.
+    assertEquals(10, serialized.length);
+
+    // Test 1: tests that invalid values aren't included in the deserialized message.
+    EnumValidityAccessors.M deserialized =
+        MessageNano.mergeFrom(new EnumValidityAccessors.M(), serialized);
+    assertEquals(EnumValidityAccessors.default_, deserialized.getOptionalE());
+    assertEquals(EnumValidityAccessors.BAZ, deserialized.getDefaultE());
+
+    // Test 2: tests that invalid values do not override previous values in the field, including
+    // pre-existing invalid values.
+    deserialized.setOptionalE(EnumValidityAccessors.BAR);
+    deserialized.setDefaultE(alsoInvalid);
+    MessageNano.mergeFrom(deserialized, serialized);
+    assertEquals(EnumValidityAccessors.BAR, deserialized.getOptionalE());
+    assertEquals(alsoInvalid, deserialized.getDefaultE());
+
+    // Test 3: reading by alternative forms
+    EnumValidityAccessors.Alt alt =
+        MessageNano.mergeFrom(new EnumValidityAccessors.Alt(), serialized);
+    assertEquals(EnumValidityAccessors.BAR, // last valid value in m.repeatedE2
+        alt.getRepeatedE2AsOptional());
+  }
+
+  /**
+   * Tests that code generation correctly wraps a single message into its outer
+   * class. The class {@code SingleMessageNano} is imported from the outer
+   * class {@code UnittestSingleNano}, whose name is implicit. Any error would
+   * cause this method to fail compilation.
+   */
+  public void testNanoSingle() throws Exception {
+    SingleMessageNano msg = new SingleMessageNano();
+    assertNotNull(msg);
+  }
+
+  /**
+   * Tests that code generation correctly skips generating the outer class if
+   * unnecessary, letting a file-scope entity have the same name. The class
+   * {@code MultipleNameClashNano} shares the same name with the file's outer
+   * class defined explicitly, but the file contains no other entities and has
+   * java_multiple_files set. Any error would cause this method to fail
+   * compilation.
+   */
+  public void testNanoMultipleNameClash() throws Exception {
+    MultipleNameClashNano msg = new MultipleNameClashNano();
+    msg.field = 0;
+  }
+
+  /**
+   * Tests that code generation correctly handles enums in different scopes in
+   * a source file with the option java_multiple_files set to true. Any error
+   * would cause this method to fail compilation.
+   */
+  public void testNanoMultipleEnumScoping() throws Exception {
+    FileScopeEnumRefNano msg1 = new FileScopeEnumRefNano();
+    msg1.enumField = UnittestMultipleNano.ONE;
+    MessageScopeEnumRefNano msg2 = new MessageScopeEnumRefNano();
+    msg2.enumField = MessageScopeEnumRefNano.TWO;
+  }
+
+  /**
+   * Tests that code generation with mixed values of the java_multiple_files
+   * options between the main source file and the imported source files would
+   * generate correct references. Any error would cause this method to fail
+   * compilation.
+   */
+  public void testNanoMultipleImportingNonMultiple() throws Exception {
+    UnittestImportNano.ImportMessageNano importMsg = new UnittestImportNano.ImportMessageNano();
+    MultipleImportingNonMultipleNano1 nano1 = new MultipleImportingNonMultipleNano1();
+    nano1.field = importMsg;
+    MultipleImportingNonMultipleNano2 nano2 = new MultipleImportingNonMultipleNano2();
+    nano2.nano1 = nano1;
+  }
+
+  public void testNanoDefaults() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    for (int i = 0; i < 2; i++) {
+      assertEquals(41, msg.defaultInt32);
+      assertEquals(42, msg.defaultInt64);
+      assertEquals(43, msg.defaultUint32);
+      assertEquals(44, msg.defaultUint64);
+      assertEquals(-45, msg.defaultSint32);
+      assertEquals(46, msg.defaultSint64);
+      assertEquals(47, msg.defaultFixed32);
+      assertEquals(48, msg.defaultFixed64);
+      assertEquals(49, msg.defaultSfixed32);
+      assertEquals(-50, msg.defaultSfixed64);
+      assertTrue(51.5f == msg.defaultFloat);
+      assertTrue(52.0e3 == msg.defaultDouble);
+      assertEquals(true, msg.defaultBool);
+      assertEquals("hello", msg.defaultString);
+      assertEquals("world", new String(msg.defaultBytes, "UTF-8"));
+      assertEquals("dünya", msg.defaultStringNonascii);
+      assertEquals("dünyab", new String(msg.defaultBytesNonascii, "UTF-8"));
+      assertEquals(TestAllTypesNano.BAR, msg.defaultNestedEnum);
+      assertEquals(NanoOuterClass.FOREIGN_NANO_BAR, msg.defaultForeignEnum);
+      assertEquals(UnittestImportNano.IMPORT_NANO_BAR, msg.defaultImportEnum);
+      assertEquals(Float.POSITIVE_INFINITY, msg.defaultFloatInf);
+      assertEquals(Float.NEGATIVE_INFINITY, msg.defaultFloatNegInf);
+      assertEquals(Float.NaN, msg.defaultFloatNan);
+      assertEquals(Double.POSITIVE_INFINITY, msg.defaultDoubleInf);
+      assertEquals(Double.NEGATIVE_INFINITY, msg.defaultDoubleNegInf);
+      assertEquals(Double.NaN, msg.defaultDoubleNan);
+
+      // Default values are not output, except for required fields.
+      byte [] result = MessageNano.toByteArray(msg);
+      int msgSerializedSize = msg.getSerializedSize();
+      //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+      assertTrue(msgSerializedSize == 3);
+      assertEquals(result.length, msgSerializedSize);
+      msg.clear();
+    }
+  }
+
+  public void testNanoWithHasParseFrom() throws Exception {
+    TestAllTypesNanoHas msg = null;
+    // Test false on creation, after clear and upon empty parse.
+    for (int i = 0; i < 3; i++) {
+      if (i == 0) {
+        msg = new TestAllTypesNanoHas();
+      } else if (i == 1) {
+        msg.clear();
+      } else if (i == 2) {
+        msg = TestAllTypesNanoHas.parseFrom(new byte[0]);
+      }
+      assertFalse(msg.hasOptionalInt32);
+      assertFalse(msg.hasOptionalString);
+      assertFalse(msg.hasOptionalBytes);
+      assertFalse(msg.hasOptionalNestedEnum);
+      assertFalse(msg.hasDefaultInt32);
+      assertFalse(msg.hasDefaultString);
+      assertFalse(msg.hasDefaultBytes);
+      assertFalse(msg.hasDefaultFloatNan);
+      assertFalse(msg.hasDefaultNestedEnum);
+      assertFalse(msg.hasId);
+      assertFalse(msg.hasRequiredEnum);
+      msg.optionalInt32 = 123;
+      msg.optionalNestedMessage = new TestAllTypesNanoHas.NestedMessage();
+      msg.optionalNestedMessage.bb = 2;
+      msg.optionalNestedEnum = TestAllTypesNano.BAZ;
+    }
+
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 10);
+    assertEquals(result.length, msgSerializedSize);
+
+    // Has fields true upon parse.
+    TestAllTypesNanoHas newMsg = TestAllTypesNanoHas.parseFrom(result);
+    assertEquals(123, newMsg.optionalInt32);
+    assertTrue(newMsg.hasOptionalInt32);
+    assertEquals(2, newMsg.optionalNestedMessage.bb);
+    assertTrue(newMsg.optionalNestedMessage.hasBb);
+    assertEquals(TestAllTypesNanoHas.BAZ, newMsg.optionalNestedEnum);
+    assertTrue(newMsg.hasOptionalNestedEnum);
+  }
+
+  public void testNanoWithHasSerialize() throws Exception {
+    TestAllTypesNanoHas msg = new TestAllTypesNanoHas();
+    msg.hasOptionalInt32 = true;
+    msg.hasOptionalString = true;
+    msg.hasOptionalBytes = true;
+    msg.optionalNestedMessage = new TestAllTypesNanoHas.NestedMessage();
+    msg.optionalNestedMessage.hasBb = true;
+    msg.hasOptionalNestedEnum = true;
+    msg.hasDefaultInt32 = true;
+    msg.hasDefaultString = true;
+    msg.hasDefaultBytes = true;
+    msg.hasDefaultFloatNan = true;
+    msg.hasDefaultNestedEnum = true;
+    msg.hasId = true;
+    msg.hasRequiredEnum = true;
+
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    assertEquals(result.length, msgSerializedSize);
+
+    // Now deserialize and find that all fields are set and equal to their defaults.
+    TestAllTypesNanoHas newMsg = TestAllTypesNanoHas.parseFrom(result);
+    assertTrue(newMsg.hasOptionalInt32);
+    assertTrue(newMsg.hasOptionalString);
+    assertTrue(newMsg.hasOptionalBytes);
+    assertTrue(newMsg.optionalNestedMessage.hasBb);
+    assertTrue(newMsg.hasOptionalNestedEnum);
+    assertTrue(newMsg.hasDefaultInt32);
+    assertTrue(newMsg.hasDefaultString);
+    assertTrue(newMsg.hasDefaultBytes);
+    assertTrue(newMsg.hasDefaultFloatNan);
+    assertTrue(newMsg.hasDefaultNestedEnum);
+    assertTrue(newMsg.hasId);
+    assertTrue(newMsg.hasRequiredEnum);
+    assertEquals(0, newMsg.optionalInt32);
+    assertEquals(0, newMsg.optionalString.length());
+    assertEquals(0, newMsg.optionalBytes.length);
+    assertEquals(0, newMsg.optionalNestedMessage.bb);
+    assertEquals(TestAllTypesNanoHas.FOO, newMsg.optionalNestedEnum);
+    assertEquals(41, newMsg.defaultInt32);
+    assertEquals("hello", newMsg.defaultString);
+    assertEquals("world", new String(newMsg.defaultBytes, "UTF-8"));
+    assertEquals(TestAllTypesNanoHas.BAR, newMsg.defaultNestedEnum);
+    assertEquals(Float.NaN, newMsg.defaultFloatNan);
+    assertEquals(0, newMsg.id);
+    assertEquals(TestAllTypesNanoHas.FOO, newMsg.requiredEnum);
+  }
+
+  public void testNanoWithAccessorsBasic() throws Exception {
+    TestNanoAccessors msg = new TestNanoAccessors();
+
+    // Makes sure required, repeated, and message fields are still public
+    msg.id = 3;
+    msg.repeatedBytes = new byte[2][3];
+    msg.optionalNestedMessage = null;
+
+    // Test accessors
+    assertEquals(0, msg.getOptionalInt32());
+    assertFalse(msg.hasOptionalInt32());
+    msg.setOptionalInt32(135);
+    assertEquals(135, msg.getOptionalInt32());
+    assertTrue(msg.hasOptionalInt32());
+    msg.clearOptionalInt32();
+    assertFalse(msg.hasOptionalInt32());
+    msg.setOptionalInt32(0); // default value
+    assertTrue(msg.hasOptionalInt32());
+
+    // Test NPE
+    try {
+      msg.setOptionalBytes(null);
+      fail();
+    } catch (NullPointerException expected) {}
+    try {
+      msg.setOptionalString(null);
+      fail();
+    } catch (NullPointerException expected) {}
+
+    // Test has bit on bytes field with defaults and clear() re-clones the default array
+    assertFalse(msg.hasDefaultBytes());
+    byte[] defaultBytes = msg.getDefaultBytes();
+    msg.setDefaultBytes(defaultBytes);
+    assertTrue(msg.hasDefaultBytes());
+    msg.clearDefaultBytes();
+    assertFalse(msg.hasDefaultBytes());
+    defaultBytes[0]++; // modify original array
+    assertFalse(Arrays.equals(defaultBytes, msg.getDefaultBytes()));
+
+    // Test has bits that require additional bit fields
+    assertFalse(msg.hasBitFieldCheck());
+    msg.setBitFieldCheck(0);
+    assertTrue(msg.hasBitFieldCheck());
+    assertFalse(msg.hasBeforeBitFieldCheck()); // checks bit field does not leak
+    assertFalse(msg.hasAfterBitFieldCheck());
+
+    // Test clear() clears has bits
+    msg.setOptionalString("hi");
+    msg.setDefaultString("there");
+    msg.clear();
+    assertFalse(msg.hasOptionalString());
+    assertFalse(msg.hasDefaultString());
+    assertFalse(msg.hasBitFieldCheck());
+
+    // Test set() and clear() returns itself (compiles = success)
+    msg.clear()
+        .setOptionalInt32(3)
+        .clearDefaultBytes()
+        .setOptionalString("4");
+  }
+
+  public void testNanoWithAccessorsParseFrom() throws Exception {
+    TestNanoAccessors msg = null;
+    // Test false on creation, after clear and upon empty parse.
+    for (int i = 0; i < 3; i++) {
+      if (i == 0) {
+        msg = new TestNanoAccessors();
+      } else if (i == 1) {
+        msg.clear();
+      } else if (i == 2) {
+        msg = TestNanoAccessors.parseFrom(new byte[0]);
+      }
+      assertFalse(msg.hasOptionalInt32());
+      assertFalse(msg.hasOptionalString());
+      assertFalse(msg.hasOptionalBytes());
+      assertFalse(msg.hasOptionalNestedEnum());
+      assertFalse(msg.hasDefaultInt32());
+      assertFalse(msg.hasDefaultString());
+      assertFalse(msg.hasDefaultBytes());
+      assertFalse(msg.hasDefaultFloatNan());
+      assertFalse(msg.hasDefaultNestedEnum());
+      msg.optionalNestedMessage = new TestNanoAccessors.NestedMessage();
+      msg.optionalNestedMessage.setBb(2);
+      msg.setOptionalNestedEnum(TestNanoAccessors.BAZ);
+      msg.setDefaultInt32(msg.getDefaultInt32());
+    }
+
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    //System.out.printf("mss=%d result.length=%d\n", msgSerializedSize, result.length);
+    assertTrue(msgSerializedSize == 14);
+    assertEquals(result.length, msgSerializedSize);
+
+    // Has fields true upon parse.
+    TestNanoAccessors newMsg = TestNanoAccessors.parseFrom(result);
+    assertEquals(2, newMsg.optionalNestedMessage.getBb());
+    assertTrue(newMsg.optionalNestedMessage.hasBb());
+    assertEquals(TestNanoAccessors.BAZ, newMsg.getOptionalNestedEnum());
+    assertTrue(newMsg.hasOptionalNestedEnum());
+
+    // Has field true on fields with explicit default values from wire.
+    assertTrue(newMsg.hasDefaultInt32());
+    assertEquals(41, newMsg.getDefaultInt32());
+  }
+
+  public void testNanoWithAccessorsPublicFieldTypes() throws Exception {
+    TestNanoAccessors msg = new TestNanoAccessors();
+    assertNull(msg.optionalNestedMessage);
+    assertEquals(0, msg.id);
+    assertEquals(0, msg.repeatedNestedEnum.length);
+
+    TestNanoAccessors newMsg = TestNanoAccessors.parseFrom(MessageNano.toByteArray(msg));
+    assertNull(newMsg.optionalNestedMessage);
+    assertEquals(0, newMsg.id);
+    assertEquals(0, newMsg.repeatedNestedEnum.length);
+
+    TestNanoAccessors.NestedMessage nestedMessage = new TestNanoAccessors.NestedMessage();
+    nestedMessage.setBb(5);
+    newMsg.optionalNestedMessage = nestedMessage;
+    newMsg.id = -1;
+    newMsg.repeatedNestedEnum = new int[] { TestAllTypesNano.FOO };
+
+    TestNanoAccessors newMsg2 = TestNanoAccessors.parseFrom(MessageNano.toByteArray(newMsg));
+    assertEquals(nestedMessage.getBb(), newMsg2.optionalNestedMessage.getBb());
+    assertEquals(-1, newMsg2.id);
+    assertEquals(TestAllTypesNano.FOO, newMsg2.repeatedNestedEnum[0]);
+
+    newMsg2.optionalNestedMessage = null;
+    newMsg2.id = 0;
+    newMsg2.repeatedNestedEnum = null;
+
+    TestNanoAccessors newMsg3 = TestNanoAccessors.parseFrom(MessageNano.toByteArray(newMsg2));
+    assertNull(newMsg3.optionalNestedMessage);
+    assertEquals(0, newMsg3.id);
+    assertEquals(0, newMsg3.repeatedNestedEnum.length);
+  }
+
+  public void testNanoWithAccessorsSerialize() throws Exception {
+    TestNanoAccessors msg = new TestNanoAccessors();
+    msg.setOptionalInt32(msg.getOptionalInt32());
+    msg.setOptionalString(msg.getOptionalString());
+    msg.setOptionalBytes(msg.getOptionalBytes());
+    TestNanoAccessors.NestedMessage nestedMessage = new TestNanoAccessors.NestedMessage();
+    nestedMessage.setBb(nestedMessage.getBb());
+    msg.optionalNestedMessage = nestedMessage;
+    msg.setOptionalNestedEnum(msg.getOptionalNestedEnum());
+    msg.setDefaultInt32(msg.getDefaultInt32());
+    msg.setDefaultString(msg.getDefaultString());
+    msg.setDefaultBytes(msg.getDefaultBytes());
+    msg.setDefaultFloatNan(msg.getDefaultFloatNan());
+    msg.setDefaultNestedEnum(msg.getDefaultNestedEnum());
+
+    byte [] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    assertEquals(result.length, msgSerializedSize);
+
+    // Now deserialize and find that all fields are set and equal to their defaults.
+    TestNanoAccessors newMsg = TestNanoAccessors.parseFrom(result);
+    assertTrue(newMsg.hasOptionalInt32());
+    assertTrue(newMsg.hasOptionalString());
+    assertTrue(newMsg.hasOptionalBytes());
+    assertTrue(newMsg.optionalNestedMessage.hasBb());
+    assertTrue(newMsg.hasOptionalNestedEnum());
+    assertTrue(newMsg.hasDefaultInt32());
+    assertTrue(newMsg.hasDefaultString());
+    assertTrue(newMsg.hasDefaultBytes());
+    assertTrue(newMsg.hasDefaultFloatNan());
+    assertTrue(newMsg.hasDefaultNestedEnum());
+    assertEquals(0, newMsg.getOptionalInt32());
+    assertEquals(0, newMsg.getOptionalString().length());
+    assertEquals(0, newMsg.getOptionalBytes().length);
+    assertEquals(0, newMsg.optionalNestedMessage.getBb());
+    assertEquals(TestNanoAccessors.FOO, newMsg.getOptionalNestedEnum());
+    assertEquals(41, newMsg.getDefaultInt32());
+    assertEquals("hello", newMsg.getDefaultString());
+    assertEquals("world", new String(newMsg.getDefaultBytes(), "UTF-8"));
+    assertEquals(TestNanoAccessors.BAR, newMsg.getDefaultNestedEnum());
+    assertEquals(Float.NaN, newMsg.getDefaultFloatNan());
+    assertEquals(0, newMsg.id);
+  }
+
+  public void testNanoJavaEnumStyle() throws Exception {
+    EnumClassNanos.EnumClassNano msg = new EnumClassNanos.EnumClassNano();
+    assertEquals(EnumClassNanos.FileScopeEnum.ONE, msg.one);
+    assertEquals(EnumClassNanos.EnumClassNano.MessageScopeEnum.TWO, msg.two);
+
+    EnumClassNanoMultiple msg2 = new EnumClassNanoMultiple();
+    assertEquals(FileScopeEnumMultiple.THREE, msg2.three);
+    assertEquals(EnumClassNanoMultiple.MessageScopeEnumMultiple.FOUR, msg2.four);
+  }
+
+  /**
+   * Tests that fields with a default value of NaN are not serialized when
+   * set to NaN. This is a special case as NaN != NaN, so normal equality
+   * checks don't work.
+   */
+  public void testNanoNotANumberDefaults() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.defaultDoubleNan = 0;
+    msg.defaultFloatNan = 0;
+    byte[] result = MessageNano.toByteArray(msg);
+    int msgSerializedSize = msg.getSerializedSize();
+    assertTrue(result.length == msgSerializedSize);
+    assertTrue(msgSerializedSize > 3);
+
+    msg.defaultDoubleNan = Double.NaN;
+    msg.defaultFloatNan = Float.NaN;
+    result = MessageNano.toByteArray(msg);
+    msgSerializedSize = msg.getSerializedSize();
+    assertEquals(3, result.length);
+    assertEquals(3, msgSerializedSize);
+  }
+
+  /**
+   * Test that a bug in skipRawBytes() has been fixed:  if the skip skips
+   * exactly up to a limit, this should not break things.
+   */
+  public void testSkipRawBytesBug() throws Exception {
+    byte[] rawBytes = new byte[] { 1, 2 };
+    CodedInputByteBufferNano input = CodedInputByteBufferNano.newInstance(rawBytes);
+
+    int limit = input.pushLimit(1);
+    input.skipRawBytes(1);
+    input.popLimit(limit);
+    assertEquals(2, input.readRawByte());
+  }
+
+  /**
+   * Test that a bug in skipRawBytes() has been fixed:  if the skip skips
+   * past the end of a buffer with a limit that has been set past the end of
+   * that buffer, this should not break things.
+   */
+  public void testSkipRawBytesPastEndOfBufferWithLimit() throws Exception {
+    byte[] rawBytes = new byte[] { 1, 2, 3, 4, 5 };
+    CodedInputByteBufferNano input = CodedInputByteBufferNano.newInstance(rawBytes);
+
+    int limit = input.pushLimit(4);
+    // In order to expose the bug we need to read at least one byte to prime the
+    // buffer inside the CodedInputStream.
+    assertEquals(1, input.readRawByte());
+    // Skip to the end of the limit.
+    input.skipRawBytes(3);
+    assertTrue(input.isAtEnd());
+    input.popLimit(limit);
+    assertEquals(5, input.readRawByte());
+  }
+
+  // Test a smattering of various proto types for printing
+  public void testMessageNanoPrinter() {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.optionalInt32 = 14;
+    msg.optionalFloat = 42.3f;
+    msg.optionalString = "String \"with' both quotes";
+    msg.optionalBytes = new byte[] {'"', '\0', 1, 8};
+    msg.optionalGroup = new TestAllTypesNano.OptionalGroup();
+    msg.optionalGroup.a = 15;
+    msg.repeatedInt64 = new long[2];
+    msg.repeatedInt64[0] = 1L;
+    msg.repeatedInt64[1] = -1L;
+    msg.repeatedBytes = new byte[2][];
+    msg.repeatedBytes[1] = new byte[] {'h', 'e', 'l', 'l', 'o'};
+    msg.repeatedGroup = new TestAllTypesNano.RepeatedGroup[2];
+    msg.repeatedGroup[0] = new TestAllTypesNano.RepeatedGroup();
+    msg.repeatedGroup[0].a = -27;
+    msg.repeatedGroup[1] = new TestAllTypesNano.RepeatedGroup();
+    msg.repeatedGroup[1].a = -72;
+    msg.optionalNestedMessage = new TestAllTypesNano.NestedMessage();
+    msg.optionalNestedMessage.bb = 7;
+    msg.repeatedNestedMessage = new TestAllTypesNano.NestedMessage[2];
+    msg.repeatedNestedMessage[0] = new TestAllTypesNano.NestedMessage();
+    msg.repeatedNestedMessage[0].bb = 77;
+    msg.repeatedNestedMessage[1] = new TestAllTypesNano.NestedMessage();
+    msg.repeatedNestedMessage[1].bb = 88;
+    msg.optionalNestedEnum = TestAllTypesNano.BAZ;
+    msg.repeatedNestedEnum = new int[2];
+    msg.repeatedNestedEnum[0] = TestAllTypesNano.BAR;
+    msg.repeatedNestedEnum[1] = TestAllTypesNano.FOO;
+    msg.repeatedStringPiece = new String[] {null, "world"};
+
+    String protoPrint = msg.toString();
+    assertTrue(protoPrint.contains("optional_int32: 14"));
+    assertTrue(protoPrint.contains("optional_float: 42.3"));
+    assertTrue(protoPrint.contains("optional_double: 0.0"));
+    assertTrue(protoPrint.contains("optional_string: \"String \\u0022with\\u0027 both quotes\""));
+    assertTrue(protoPrint.contains("optional_bytes: \"\\\"\\000\\001\\010\""));
+    assertTrue(protoPrint.contains("optional_group <\n  a: 15\n>"));
+
+    assertTrue(protoPrint.contains("repeated_int64: 1\nrepeated_int64: -1"));
+    assertFalse(protoPrint.contains("repeated_bytes: \"\"")); // null should be dropped
+    assertTrue(protoPrint.contains("repeated_bytes: \"hello\""));
+    assertTrue(protoPrint.contains("repeated_group <\n  a: -27\n>\n"
+            + "repeated_group <\n  a: -72\n>"));
+    assertTrue(protoPrint.contains("optional_nested_message <\n  bb: 7\n>"));
+    assertTrue(protoPrint.contains("repeated_nested_message <\n  bb: 77\n>\n"
+            + "repeated_nested_message <\n  bb: 88\n>"));
+    assertTrue(protoPrint.contains("optional_nested_enum: 3"));
+    assertTrue(protoPrint.contains("repeated_nested_enum: 2\nrepeated_nested_enum: 1"));
+    assertTrue(protoPrint.contains("default_int32: 41"));
+    assertTrue(protoPrint.contains("default_string: \"hello\""));
+    assertFalse(protoPrint.contains("repeated_string_piece: \"\""));  // null should be dropped
+    assertTrue(protoPrint.contains("repeated_string_piece: \"world\""));
+  }
+
+  public void testMessageNanoPrinterAccessors() throws Exception {
+    TestNanoAccessors msg = new TestNanoAccessors();
+    msg.setOptionalInt32(13);
+    msg.setOptionalString("foo");
+    msg.setOptionalBytes(new byte[] {'"', '\0', 1, 8});
+    msg.optionalNestedMessage = new TestNanoAccessors.NestedMessage();
+    msg.optionalNestedMessage.setBb(7);
+    msg.setOptionalNestedEnum(TestNanoAccessors.BAZ);
+    msg.repeatedInt32 = new int[] { 1, -1 };
+    msg.repeatedString = new String[] { "Hello", "world" };
+    msg.repeatedBytes = new byte[2][];
+    msg.repeatedBytes[1] = new byte[] {'h', 'e', 'l', 'l', 'o'};
+    msg.repeatedNestedMessage = new TestNanoAccessors.NestedMessage[2];
+    msg.repeatedNestedMessage[0] = new TestNanoAccessors.NestedMessage();
+    msg.repeatedNestedMessage[0].setBb(5);
+    msg.repeatedNestedMessage[1] = new TestNanoAccessors.NestedMessage();
+    msg.repeatedNestedMessage[1].setBb(6);
+    msg.repeatedNestedEnum = new int[] { TestNanoAccessors.FOO, TestNanoAccessors.BAR };
+    msg.id = 33;
+
+    String protoPrint = msg.toString();
+    assertTrue(protoPrint.contains("optional_int32: 13"));
+    assertTrue(protoPrint.contains("optional_string: \"foo\""));
+    assertTrue(protoPrint.contains("optional_bytes: \"\\\"\\000\\001\\010\""));
+    assertTrue(protoPrint.contains("optional_nested_message <\n  bb: 7\n>"));
+    assertTrue(protoPrint.contains("optional_nested_enum: 3"));
+    assertTrue(protoPrint.contains("repeated_int32: 1\nrepeated_int32: -1"));
+    assertTrue(protoPrint.contains("repeated_string: \"Hello\"\nrepeated_string: \"world\""));
+    assertFalse(protoPrint.contains("repeated_bytes: \"\"")); // null should be dropped
+    assertTrue(protoPrint.contains("repeated_bytes: \"hello\""));
+    assertTrue(protoPrint.contains("repeated_nested_message <\n  bb: 5\n>\n"
+            + "repeated_nested_message <\n  bb: 6\n>"));
+    assertTrue(protoPrint.contains("repeated_nested_enum: 1\nrepeated_nested_enum: 2"));
+    assertTrue(protoPrint.contains("id: 33"));
+  }
+
+  public void testExtensions() throws Exception {
+    Extensions.ExtendableMessage message = new Extensions.ExtendableMessage();
+    message.field = 5;
+    int[] int32s = {1, 2};
+    int[] uint32s = {3, 4};
+    int[] sint32s = {-5, -6};
+    long[] int64s = {7, 8};
+    long[] uint64s = {9, 10};
+    long[] sint64s = {-11, -12};
+    int[] fixed32s = {13, 14};
+    int[] sfixed32s = {-15, -16};
+    long[] fixed64s = {17, 18};
+    long[] sfixed64s = {-19, -20};
+    boolean[] bools = {true, false};
+    float[] floats = {2.1f, 2.2f};
+    double[] doubles = {2.3, 2.4};
+    int[] enums = {Extensions.SECOND_VALUE, Extensions.FIRST_VALUE};
+    String[] strings = {"vijfentwintig", "twenty-six"};
+    byte[][] bytess = {{2, 7}, {2, 8}};
+    AnotherMessage another1 = new AnotherMessage();
+    another1.string = "er shi jiu";
+    another1.value = false;
+    AnotherMessage another2 = new AnotherMessage();
+    another2.string = "trente";
+    another2.value = true;
+    AnotherMessage[] messages = {another1, another2};
+    RepeatedExtensions.RepeatedGroup group1 = new RepeatedExtensions.RepeatedGroup();
+    group1.a = 31;
+    RepeatedExtensions.RepeatedGroup group2 = new RepeatedExtensions.RepeatedGroup();
+    group2.a = 32;
+    RepeatedExtensions.RepeatedGroup[] groups = {group1, group2};
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedInt32));
+    message.setExtension(RepeatedExtensions.repeatedInt32, int32s);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedInt32));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedUint32));
+    message.setExtension(RepeatedExtensions.repeatedUint32, uint32s);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedUint32));
+    message.setExtension(RepeatedExtensions.repeatedSint32, sint32s);
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedInt64));
+    message.setExtension(RepeatedExtensions.repeatedInt64, int64s);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedInt64));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedUint64));
+    message.setExtension(RepeatedExtensions.repeatedUint64, uint64s);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedUint64));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedSint64));
+    message.setExtension(RepeatedExtensions.repeatedSint64, sint64s);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedSint64));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedFixed32));
+    message.setExtension(RepeatedExtensions.repeatedFixed32, fixed32s);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedFixed32));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedSfixed32));
+    message.setExtension(RepeatedExtensions.repeatedSfixed32, sfixed32s);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedSfixed32));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedFixed64));
+    message.setExtension(RepeatedExtensions.repeatedFixed64, fixed64s);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedFixed64));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedSfixed64));
+    message.setExtension(RepeatedExtensions.repeatedSfixed64, sfixed64s);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedSfixed64));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedBool));
+    message.setExtension(RepeatedExtensions.repeatedBool, bools);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedBool));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedFloat));
+    message.setExtension(RepeatedExtensions.repeatedFloat, floats);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedFloat));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedDouble));
+    message.setExtension(RepeatedExtensions.repeatedDouble, doubles);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedDouble));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedEnum));
+    message.setExtension(RepeatedExtensions.repeatedEnum, enums);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedEnum));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedString));
+    message.setExtension(RepeatedExtensions.repeatedString, strings);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedString));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedBytes));
+    message.setExtension(RepeatedExtensions.repeatedBytes, bytess);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedBytes));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedMessage));
+    message.setExtension(RepeatedExtensions.repeatedMessage, messages);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedMessage));
+    assertFalse(message.hasExtension(RepeatedExtensions.repeatedGroup));
+    message.setExtension(RepeatedExtensions.repeatedGroup, groups);
+    assertTrue(message.hasExtension(RepeatedExtensions.repeatedGroup));
+
+    byte[] data = MessageNano.toByteArray(message);
+    message = Extensions.ExtendableMessage.parseFrom(data);
+    assertEquals(5, message.field);
+
+    // Test reading back using SingularExtensions: the retrieved value should equal the last
+    // in each array.
+    assertEquals(int32s[1], (int) message.getExtension(SingularExtensions.someInt32));
+    assertEquals(uint32s[1], (int) message.getExtension(SingularExtensions.someUint32));
+    assertEquals(sint32s[1], (int) message.getExtension(SingularExtensions.someSint32));
+    assertEquals(int64s[1], (long) message.getExtension(SingularExtensions.someInt64));
+    assertEquals(uint64s[1], (long) message.getExtension(SingularExtensions.someUint64));
+    assertEquals(sint64s[1], (long) message.getExtension(SingularExtensions.someSint64));
+    assertEquals(fixed32s[1], (int) message.getExtension(SingularExtensions.someFixed32));
+    assertEquals(sfixed32s[1], (int) message.getExtension(SingularExtensions.someSfixed32));
+    assertEquals(fixed64s[1], (long) message.getExtension(SingularExtensions.someFixed64));
+    assertEquals(sfixed64s[1], (long) message.getExtension(SingularExtensions.someSfixed64));
+    assertEquals(bools[1], (boolean) message.getExtension(SingularExtensions.someBool));
+    assertEquals(floats[1], (float) message.getExtension(SingularExtensions.someFloat));
+    assertEquals(doubles[1], (double) message.getExtension(SingularExtensions.someDouble));
+    assertEquals(enums[1], (int) message.getExtension(SingularExtensions.someEnum));
+    assertEquals(strings[1], message.getExtension(SingularExtensions.someString));
+    assertTrue(Arrays.equals(bytess[1], message.getExtension(SingularExtensions.someBytes)));
+    AnotherMessage deserializedMessage = message.getExtension(SingularExtensions.someMessage);
+    assertEquals(another2.string, deserializedMessage.string);
+    assertEquals(another2.value, deserializedMessage.value);
+    assertEquals(group2.a, message.getExtension(SingularExtensions.someGroup).a);
+
+    // Test reading back using RepeatedExtensions: the arrays should be equal.
+    message = Extensions.ExtendableMessage.parseFrom(data);
+    assertEquals(5, message.field);
+    assertTrue(Arrays.equals(int32s, message.getExtension(RepeatedExtensions.repeatedInt32)));
+    assertTrue(Arrays.equals(uint32s, message.getExtension(RepeatedExtensions.repeatedUint32)));
+    assertTrue(Arrays.equals(sint32s, message.getExtension(RepeatedExtensions.repeatedSint32)));
+    assertTrue(Arrays.equals(int64s, message.getExtension(RepeatedExtensions.repeatedInt64)));
+    assertTrue(Arrays.equals(uint64s, message.getExtension(RepeatedExtensions.repeatedUint64)));
+    assertTrue(Arrays.equals(sint64s, message.getExtension(RepeatedExtensions.repeatedSint64)));
+    assertTrue(Arrays.equals(fixed32s, message.getExtension(RepeatedExtensions.repeatedFixed32)));
+    assertTrue(Arrays.equals(sfixed32s, message.getExtension(RepeatedExtensions.repeatedSfixed32)));
+    assertTrue(Arrays.equals(fixed64s, message.getExtension(RepeatedExtensions.repeatedFixed64)));
+    assertTrue(Arrays.equals(sfixed64s, message.getExtension(RepeatedExtensions.repeatedSfixed64)));
+    assertTrue(Arrays.equals(bools, message.getExtension(RepeatedExtensions.repeatedBool)));
+    assertTrue(Arrays.equals(floats, message.getExtension(RepeatedExtensions.repeatedFloat)));
+    assertTrue(Arrays.equals(doubles, message.getExtension(RepeatedExtensions.repeatedDouble)));
+    assertTrue(Arrays.equals(enums, message.getExtension(RepeatedExtensions.repeatedEnum)));
+    assertTrue(Arrays.equals(strings, message.getExtension(RepeatedExtensions.repeatedString)));
+    byte[][] deserializedRepeatedBytes = message.getExtension(RepeatedExtensions.repeatedBytes);
+    assertEquals(2, deserializedRepeatedBytes.length);
+    assertTrue(Arrays.equals(bytess[0], deserializedRepeatedBytes[0]));
+    assertTrue(Arrays.equals(bytess[1], deserializedRepeatedBytes[1]));
+    AnotherMessage[] deserializedRepeatedMessage =
+        message.getExtension(RepeatedExtensions.repeatedMessage);
+    assertEquals(2, deserializedRepeatedMessage.length);
+    assertEquals(another1.string, deserializedRepeatedMessage[0].string);
+    assertEquals(another1.value, deserializedRepeatedMessage[0].value);
+    assertEquals(another2.string, deserializedRepeatedMessage[1].string);
+    assertEquals(another2.value, deserializedRepeatedMessage[1].value);
+    RepeatedExtensions.RepeatedGroup[] deserializedRepeatedGroup =
+        message.getExtension(RepeatedExtensions.repeatedGroup);
+    assertEquals(2, deserializedRepeatedGroup.length);
+    assertEquals(group1.a, deserializedRepeatedGroup[0].a);
+    assertEquals(group2.a, deserializedRepeatedGroup[1].a);
+
+    message = Extensions.ExtendableMessage.parseFrom(data);
+    assertEquals(5, message.field);
+    // Test hasExtension using PackedExtensions.
+    assertTrue(message.hasExtension(PackedExtensions.packedInt32));
+    assertTrue(message.hasExtension(PackedExtensions.packedUint32));
+    assertTrue(message.hasExtension(PackedExtensions.packedSint32));
+    assertTrue(message.hasExtension(PackedExtensions.packedInt64));
+    assertTrue(message.hasExtension(PackedExtensions.packedUint64));
+    assertTrue(message.hasExtension(PackedExtensions.packedSint64));
+    assertTrue(message.hasExtension(PackedExtensions.packedFixed32));
+    assertTrue(message.hasExtension(PackedExtensions.packedSfixed32));
+    assertTrue(message.hasExtension(PackedExtensions.packedFixed64));
+    assertTrue(message.hasExtension(PackedExtensions.packedSfixed64));
+    assertTrue(message.hasExtension(PackedExtensions.packedBool));
+    assertTrue(message.hasExtension(PackedExtensions.packedFloat));
+    assertTrue(message.hasExtension(PackedExtensions.packedDouble));
+    assertTrue(message.hasExtension(PackedExtensions.packedEnum));
+
+    // Test reading back using PackedExtensions: the arrays should be equal, even the fields
+    // are non-packed.
+    assertTrue(Arrays.equals(int32s, message.getExtension(PackedExtensions.packedInt32)));
+    assertTrue(Arrays.equals(uint32s, message.getExtension(PackedExtensions.packedUint32)));
+    assertTrue(Arrays.equals(sint32s, message.getExtension(PackedExtensions.packedSint32)));
+    assertTrue(Arrays.equals(int64s, message.getExtension(PackedExtensions.packedInt64)));
+    assertTrue(Arrays.equals(uint64s, message.getExtension(PackedExtensions.packedUint64)));
+    assertTrue(Arrays.equals(sint64s, message.getExtension(PackedExtensions.packedSint64)));
+    assertTrue(Arrays.equals(fixed32s, message.getExtension(PackedExtensions.packedFixed32)));
+    assertTrue(Arrays.equals(sfixed32s, message.getExtension(PackedExtensions.packedSfixed32)));
+    assertTrue(Arrays.equals(fixed64s, message.getExtension(PackedExtensions.packedFixed64)));
+    assertTrue(Arrays.equals(sfixed64s, message.getExtension(PackedExtensions.packedSfixed64)));
+    assertTrue(Arrays.equals(bools, message.getExtension(PackedExtensions.packedBool)));
+    assertTrue(Arrays.equals(floats, message.getExtension(PackedExtensions.packedFloat)));
+    assertTrue(Arrays.equals(doubles, message.getExtension(PackedExtensions.packedDouble)));
+    assertTrue(Arrays.equals(enums, message.getExtension(PackedExtensions.packedEnum)));
+
+    // Now set the packable extension values using PackedExtensions so they're serialized packed.
+    message.setExtension(PackedExtensions.packedInt32, int32s);
+    message.setExtension(PackedExtensions.packedUint32, uint32s);
+    message.setExtension(PackedExtensions.packedSint32, sint32s);
+    message.setExtension(PackedExtensions.packedInt64, int64s);
+    message.setExtension(PackedExtensions.packedUint64, uint64s);
+    message.setExtension(PackedExtensions.packedSint64, sint64s);
+    message.setExtension(PackedExtensions.packedFixed32, fixed32s);
+    message.setExtension(PackedExtensions.packedSfixed32, sfixed32s);
+    message.setExtension(PackedExtensions.packedFixed64, fixed64s);
+    message.setExtension(PackedExtensions.packedSfixed64, sfixed64s);
+    message.setExtension(PackedExtensions.packedBool, bools);
+    message.setExtension(PackedExtensions.packedFloat, floats);
+    message.setExtension(PackedExtensions.packedDouble, doubles);
+    message.setExtension(PackedExtensions.packedEnum, enums);
+
+    // And read back using non-packed RepeatedExtensions.
+    byte[] data2 = MessageNano.toByteArray(message);
+    message = MessageNano.mergeFrom(new Extensions.ExtendableMessage(), data2);
+    assertTrue(Arrays.equals(int32s, message.getExtension(RepeatedExtensions.repeatedInt32)));
+    assertTrue(Arrays.equals(uint32s, message.getExtension(RepeatedExtensions.repeatedUint32)));
+    assertTrue(Arrays.equals(sint32s, message.getExtension(RepeatedExtensions.repeatedSint32)));
+    assertTrue(Arrays.equals(int64s, message.getExtension(RepeatedExtensions.repeatedInt64)));
+    assertTrue(Arrays.equals(uint64s, message.getExtension(RepeatedExtensions.repeatedUint64)));
+    assertTrue(Arrays.equals(sint64s, message.getExtension(RepeatedExtensions.repeatedSint64)));
+    assertTrue(Arrays.equals(fixed32s, message.getExtension(RepeatedExtensions.repeatedFixed32)));
+    assertTrue(Arrays.equals(sfixed32s, message.getExtension(RepeatedExtensions.repeatedSfixed32)));
+    assertTrue(Arrays.equals(fixed64s, message.getExtension(RepeatedExtensions.repeatedFixed64)));
+    assertTrue(Arrays.equals(sfixed64s, message.getExtension(RepeatedExtensions.repeatedSfixed64)));
+    assertTrue(Arrays.equals(bools, message.getExtension(RepeatedExtensions.repeatedBool)));
+    assertTrue(Arrays.equals(floats, message.getExtension(RepeatedExtensions.repeatedFloat)));
+    assertTrue(Arrays.equals(doubles, message.getExtension(RepeatedExtensions.repeatedDouble)));
+    assertTrue(Arrays.equals(enums, message.getExtension(RepeatedExtensions.repeatedEnum)));
+  }
+
+  public void testNullExtensions() throws Exception {
+    // Check that clearing the extension on an empty message is a no-op.
+    Extensions.ExtendableMessage message = new Extensions.ExtendableMessage();
+    assertFalse(message.hasExtension(SingularExtensions.someMessage));
+    message.setExtension(SingularExtensions.someMessage, null);
+    assertFalse(message.hasExtension(SingularExtensions.someMessage));
+    assertEquals(0, MessageNano.toByteArray(message).length);
+
+    // Check that the message is empty after setting and clearing an extension.
+    AnotherMessage another = new AnotherMessage();
+    assertFalse(message.hasExtension(SingularExtensions.someMessage));
+    message.setExtension(SingularExtensions.someMessage, another);
+    assertTrue(message.hasExtension(SingularExtensions.someMessage));
+    assertTrue(MessageNano.toByteArray(message).length > 0);
+    message.setExtension(SingularExtensions.someMessage, null);
+    assertFalse(message.hasExtension(SingularExtensions.someMessage));
+    assertEquals(0, MessageNano.toByteArray(message).length);
+  }
+
+  public void testExtensionsMutation() {
+    Extensions.ExtendableMessage extendableMessage = new Extensions.ExtendableMessage();
+    extendableMessage.setExtension(SingularExtensions.someMessage,
+        new Extensions.AnotherMessage());
+
+    extendableMessage.getExtension(SingularExtensions.someMessage).string = "not empty";
+
+    assertEquals("not empty",
+        extendableMessage.getExtension(SingularExtensions.someMessage).string);
+  }
+
+  public void testExtensionsMutation_Equals() throws InvalidProtocolBufferNanoException {
+    Extensions.ExtendableMessage extendableMessage = new Extensions.ExtendableMessage();
+    extendableMessage.field = 5;
+    int int32 = 42;
+    int[] uint32s = {3, 4};
+    int[] sint32s = {-5, -6};
+    long[] int64s = {7, 8};
+    long[] uint64s = {9, 10};
+    long[] sint64s = {-11, -12};
+    int[] fixed32s = {13, 14};
+    int[] sfixed32s = {-15, -16};
+    long[] fixed64s = {17, 18};
+    long[] sfixed64s = {-19, -20};
+    boolean[] bools = {true, false};
+    float[] floats = {2.1f, 2.2f};
+    double[] doubles = {2.3, 2.4};
+    int[] enums = {Extensions.SECOND_VALUE, Extensions.FIRST_VALUE};
+    String[] strings = {"vijfentwintig", "twenty-six"};
+    byte[][] bytess = {{2, 7}, {2, 8}};
+    AnotherMessage another1 = new AnotherMessage();
+    another1.string = "er shi jiu";
+    another1.value = false;
+    AnotherMessage another2 = new AnotherMessage();
+    another2.string = "trente";
+    another2.value = true;
+    AnotherMessage[] messages = {another1, another2};
+    RepeatedExtensions.RepeatedGroup group1 = new RepeatedExtensions.RepeatedGroup();
+    group1.a = 31;
+    RepeatedExtensions.RepeatedGroup group2 = new RepeatedExtensions.RepeatedGroup();
+    group2.a = 32;
+    RepeatedExtensions.RepeatedGroup[] groups = {group1, group2};
+    extendableMessage.setExtension(SingularExtensions.someInt32, int32);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedUint32, uint32s);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedSint32, sint32s);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedInt64, int64s);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedUint64, uint64s);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedSint64, sint64s);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedFixed32, fixed32s);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedSfixed32, sfixed32s);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedFixed64, fixed64s);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedSfixed64, sfixed64s);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedBool, bools);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedFloat, floats);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedDouble, doubles);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedEnum, enums);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedString, strings);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedBytes, bytess);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedMessage, messages);
+    extendableMessage.setExtension(RepeatedExtensions.repeatedGroup, groups);
+
+    byte[] data = MessageNano.toByteArray(extendableMessage);
+
+    extendableMessage = Extensions.ExtendableMessage.parseFrom(data);
+    Extensions.ExtendableMessage messageCopy = Extensions.ExtendableMessage.parseFrom(data);
+
+    // Without deserialising.
+    assertEquals(extendableMessage, messageCopy);
+    assertEquals(extendableMessage.hashCode(), messageCopy.hashCode());
+
+    // Only one deserialized.
+    extendableMessage.getExtension(SingularExtensions.someInt32);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedUint32);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedSint32);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedInt64);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedUint64);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedSint64);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedFixed32);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedSfixed32);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedFixed64);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedSfixed64);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedBool);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedFloat);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedDouble);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedEnum);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedString);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedBytes);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedMessage);
+    extendableMessage.getExtension(RepeatedExtensions.repeatedGroup);
+    assertEquals(extendableMessage, messageCopy);
+    assertEquals(extendableMessage.hashCode(), messageCopy.hashCode());
+
+    // Both deserialized.
+    messageCopy.getExtension(SingularExtensions.someInt32);
+    messageCopy.getExtension(RepeatedExtensions.repeatedUint32);
+    messageCopy.getExtension(RepeatedExtensions.repeatedSint32);
+    messageCopy.getExtension(RepeatedExtensions.repeatedInt64);
+    messageCopy.getExtension(RepeatedExtensions.repeatedUint64);
+    messageCopy.getExtension(RepeatedExtensions.repeatedSint64);
+    messageCopy.getExtension(RepeatedExtensions.repeatedFixed32);
+    messageCopy.getExtension(RepeatedExtensions.repeatedSfixed32);
+    messageCopy.getExtension(RepeatedExtensions.repeatedFixed64);
+    messageCopy.getExtension(RepeatedExtensions.repeatedSfixed64);
+    messageCopy.getExtension(RepeatedExtensions.repeatedBool);
+    messageCopy.getExtension(RepeatedExtensions.repeatedFloat);
+    messageCopy.getExtension(RepeatedExtensions.repeatedDouble);
+    messageCopy.getExtension(RepeatedExtensions.repeatedEnum);
+    messageCopy.getExtension(RepeatedExtensions.repeatedString);
+    messageCopy.getExtension(RepeatedExtensions.repeatedBytes);
+    messageCopy.getExtension(RepeatedExtensions.repeatedMessage);
+    messageCopy.getExtension(RepeatedExtensions.repeatedGroup);
+    assertEquals(extendableMessage, messageCopy);
+    assertEquals(extendableMessage.hashCode(), messageCopy.hashCode());
+
+    // Change one, make sure they are still different.
+    messageCopy.getExtension(RepeatedExtensions.repeatedMessage)[0].string = "not empty";
+    assertFalse(extendableMessage.equals(messageCopy));
+
+    // Even if the extension hasn't been deserialized.
+    extendableMessage = Extensions.ExtendableMessage.parseFrom(data);
+    assertFalse(extendableMessage.equals(messageCopy));
+  }
+
+  public void testExtensionsCaching() {
+    Extensions.ExtendableMessage extendableMessage = new Extensions.ExtendableMessage();
+    extendableMessage.setExtension(SingularExtensions.someMessage,
+        new Extensions.AnotherMessage());
+    assertSame("Consecutive calls to getExtensions should return the same object",
+        extendableMessage.getExtension(SingularExtensions.someMessage),
+        extendableMessage.getExtension(SingularExtensions.someMessage));
+  }
+
+  public void testUnknownFields() throws Exception {
+    // Check that we roundtrip (serialize and deserialize) unrecognized fields.
+    AnotherMessage message = new AnotherMessage();
+    message.string = "Hello World";
+    message.value = false;
+
+    byte[] bytes = MessageNano.toByteArray(message);
+    int extraFieldSize = CodedOutputByteBufferNano.computeStringSize(
+        1001, "This is an unknown field");
+    byte[] newBytes = new byte[bytes.length + extraFieldSize];
+    System.arraycopy(bytes, 0, newBytes, 0, bytes.length);
+    CodedOutputByteBufferNano.newInstance(newBytes, bytes.length, extraFieldSize)
+        .writeString(1001, "This is an unknown field");
+
+    // Deserialize with an unknown field.
+    AnotherMessage deserialized = AnotherMessage.parseFrom(newBytes);
+    byte[] serialized = MessageNano.toByteArray(deserialized);
+
+    assertEquals(newBytes.length, serialized.length);
+
+    // Clear, and make sure it clears everything.
+    deserialized.clear();
+    assertEquals(0, MessageNano.toByteArray(deserialized).length);
+  }
+
+  public void testMergeFrom() throws Exception {
+    SimpleMessageNano message = new SimpleMessageNano();
+    message.d = 123;
+    byte[] bytes = MessageNano.toByteArray(message);
+
+    SimpleMessageNano newMessage = MessageNano.mergeFrom(new SimpleMessageNano(), bytes);
+    assertEquals(message.d, newMessage.d);
+  }
+
+  public void testJavaKeyword() throws Exception {
+    TestAllTypesNano msg = new TestAllTypesNano();
+    msg.synchronized_ = 123;
+    assertEquals(123, msg.synchronized_);
+  }
+
+  public void testReferenceTypesForPrimitives() throws Exception {
+    NanoReferenceTypes.TestAllTypesNano message = new NanoReferenceTypes.TestAllTypesNano();
+
+    // Base check - when nothing is set, we serialize nothing.
+    assertHasWireData(message, false);
+
+    message.defaultBool = true;
+    assertHasWireData(message, true);
+
+    message.defaultBool = false;
+    assertHasWireData(message, true);
+
+    message.defaultBool = null;
+    assertHasWireData(message, false);
+
+    message.defaultInt32 = 5;
+    assertHasWireData(message, true);
+
+    message.defaultInt32 = null;
+    assertHasWireData(message, false);
+
+    message.defaultInt64 = 123456L;
+    assertHasWireData(message, true);
+
+    message.defaultInt64 = null;
+    assertHasWireData(message, false);
+
+    message.defaultFloat = 1f;
+    assertHasWireData(message, true);
+
+    message.defaultFloat = null;
+    assertHasWireData(message, false);
+
+    message.defaultDouble = 2.1;
+    assertHasWireData(message, true);
+
+    message.defaultDouble = null;
+    assertHasWireData(message, false);
+
+    message.defaultString = "hello";
+    assertHasWireData(message, true);
+
+    message.defaultString = null;
+    assertHasWireData(message, false);
+
+    message.defaultBytes = new byte[] { 1, 2, 3 };
+    assertHasWireData(message, true);
+
+    message.defaultBytes = null;
+    assertHasWireData(message, false);
+  }
+
+  public void testHashCodeEquals() throws Exception {
+    // Complete equality:
+    TestAllTypesNano a = createMessageForHashCodeEqualsTest();
+    TestAllTypesNano aEquivalent = createMessageForHashCodeEqualsTest();
+
+    assertTrue(MessageNano.messageNanoEquals(a, aEquivalent));
+    assertFalse(MessageNano.messageNanoEquals(a, new TestAllTypesNano()));
+
+    // Null and empty array for repeated fields equality:
+    TestAllTypesNano b = createMessageForHashCodeEqualsTest();
+    b.repeatedBool = null;
+    b.repeatedFloat = new float[0];
+    TestAllTypesNano bEquivalent = createMessageForHashCodeEqualsTest();
+    bEquivalent.repeatedBool = new boolean[0];
+    bEquivalent.repeatedFloat = null;
+
+    // Ref-element-type repeated fields use non-null subsequence equality:
+    TestAllTypesNano c = createMessageForHashCodeEqualsTest();
+    c.repeatedString = null;
+    c.repeatedStringPiece = new String[] {null, "one", null, "two"};
+    c.repeatedBytes = new byte[][] {{3, 4}, null};
+    TestAllTypesNano cEquivalent = createMessageForHashCodeEqualsTest();
+    cEquivalent.repeatedString = new String[3];
+    cEquivalent.repeatedStringPiece = new String[] {"one", "two", null};
+    cEquivalent.repeatedBytes = new byte[][] {{3, 4}};
+
+    // Complete equality for messages with has fields:
+    TestAllTypesNanoHas d = createMessageWithHasForHashCodeEqualsTest();
+    TestAllTypesNanoHas dEquivalent = createMessageWithHasForHashCodeEqualsTest();
+
+    // If has-fields exist, fields with the same default values but
+    // different has-field values are different.
+    TestAllTypesNanoHas e = createMessageWithHasForHashCodeEqualsTest();
+    e.optionalInt32++; // make different from d
+    e.hasDefaultString = false;
+    TestAllTypesNanoHas eDifferent = createMessageWithHasForHashCodeEqualsTest();
+    eDifferent.optionalInt32 = e.optionalInt32;
+    eDifferent.hasDefaultString = true;
+
+    // Complete equality for messages with accessors:
+    TestNanoAccessors f = createMessageWithAccessorsForHashCodeEqualsTest();
+    TestNanoAccessors fEquivalent = createMessageWithAccessorsForHashCodeEqualsTest();
+
+    // If using accessors, explicitly setting a field to its default value
+    // should make the message different.
+    TestNanoAccessors g = createMessageWithAccessorsForHashCodeEqualsTest();
+    g.setOptionalInt32(g.getOptionalInt32() + 1); // make different from f
+    g.clearDefaultString();
+    TestNanoAccessors gDifferent = createMessageWithAccessorsForHashCodeEqualsTest();
+    gDifferent.setOptionalInt32(g.getOptionalInt32());
+    gDifferent.setDefaultString(g.getDefaultString());
+
+    // Complete equality for reference typed messages:
+    NanoReferenceTypes.TestAllTypesNano h = createRefTypedMessageForHashCodeEqualsTest();
+    NanoReferenceTypes.TestAllTypesNano hEquivalent = createRefTypedMessageForHashCodeEqualsTest();
+
+    // Inequality of null and default value for reference typed messages:
+    NanoReferenceTypes.TestAllTypesNano i = createRefTypedMessageForHashCodeEqualsTest();
+    i.optionalInt32 = 1; // make different from h
+    i.optionalFloat = null;
+    NanoReferenceTypes.TestAllTypesNano iDifferent = createRefTypedMessageForHashCodeEqualsTest();
+    iDifferent.optionalInt32 = i.optionalInt32;
+    iDifferent.optionalFloat = 0.0f;
+
+    HashMap<MessageNano, String> hashMap = new HashMap<MessageNano, String>();
+    hashMap.put(a, "a");
+    hashMap.put(b, "b");
+    hashMap.put(c, "c");
+    hashMap.put(d, "d");
+    hashMap.put(e, "e");
+    hashMap.put(f, "f");
+    hashMap.put(g, "g");
+    hashMap.put(h, "h");
+    hashMap.put(i, "i");
+
+    assertEquals(9, hashMap.size()); // a-i should be different from each other.
+
+    assertEquals("a", hashMap.get(a));
+    assertEquals("a", hashMap.get(aEquivalent));
+
+    assertEquals("b", hashMap.get(b));
+    assertEquals("b", hashMap.get(bEquivalent));
+
+    assertEquals("c", hashMap.get(c));
+    assertEquals("c", hashMap.get(cEquivalent));
+
+    assertEquals("d", hashMap.get(d));
+    assertEquals("d", hashMap.get(dEquivalent));
+
+    assertEquals("e", hashMap.get(e));
+    assertNull(hashMap.get(eDifferent));
+
+    assertEquals("f", hashMap.get(f));
+    assertEquals("f", hashMap.get(fEquivalent));
+
+    assertEquals("g", hashMap.get(g));
+    assertNull(hashMap.get(gDifferent));
+
+    assertEquals("h", hashMap.get(h));
+    assertEquals("h", hashMap.get(hEquivalent));
+
+    assertEquals("i", hashMap.get(i));
+    assertNull(hashMap.get(iDifferent));
+  }
+
+  private TestAllTypesNano createMessageForHashCodeEqualsTest() {
+    TestAllTypesNano message = new TestAllTypesNano();
+    message.optionalInt32 = 5;
+    message.optionalInt64 = 777;
+    message.optionalFloat = 1.0f;
+    message.optionalDouble = 2.0;
+    message.optionalBool = true;
+    message.optionalString = "Hello";
+    message.optionalBytes = new byte[] { 1, 2, 3 };
+    message.optionalNestedMessage = new TestAllTypesNano.NestedMessage();
+    message.optionalNestedMessage.bb = 27;
+    message.optionalNestedEnum = TestAllTypesNano.BAR;
+    message.repeatedInt32 = new int[] { 5, 6, 7, 8 };
+    message.repeatedInt64 = new long[] { 27L, 28L, 29L };
+    message.repeatedFloat = new float[] { 5.0f, 6.0f };
+    message.repeatedDouble = new double[] { 99.1, 22.5 };
+    message.repeatedBool = new boolean[] { true, false, true };
+    message.repeatedString = new String[] { "One", "Two" };
+    message.repeatedBytes = new byte[][] { { 2, 7 }, { 2, 7 } };
+    message.repeatedNestedMessage = new TestAllTypesNano.NestedMessage[] {
+      message.optionalNestedMessage,
+      message.optionalNestedMessage
+    };
+    message.repeatedNestedEnum = new int[] {
+      TestAllTypesNano.BAR,
+      TestAllTypesNano.BAZ
+    };
+    return message;
+  }
+
+  private TestAllTypesNanoHas createMessageWithHasForHashCodeEqualsTest() {
+    TestAllTypesNanoHas message = new TestAllTypesNanoHas();
+    message.optionalInt32 = 5;
+    message.optionalString = "Hello";
+    message.optionalBytes = new byte[] { 1, 2, 3 };
+    message.optionalNestedMessage = new TestAllTypesNanoHas.NestedMessage();
+    message.optionalNestedMessage.bb = 27;
+    message.optionalNestedEnum = TestAllTypesNano.BAR;
+    message.repeatedInt32 = new int[] { 5, 6, 7, 8 };
+    message.repeatedString = new String[] { "One", "Two" };
+    message.repeatedBytes = new byte[][] { { 2, 7 }, { 2, 7 } };
+    message.repeatedNestedMessage = new TestAllTypesNanoHas.NestedMessage[] {
+      message.optionalNestedMessage,
+      message.optionalNestedMessage
+    };
+    message.repeatedNestedEnum = new int[] {
+      TestAllTypesNano.BAR,
+      TestAllTypesNano.BAZ
+    };
+    return message;
+  }
+
+  private TestNanoAccessors createMessageWithAccessorsForHashCodeEqualsTest() {
+    TestNanoAccessors message = new TestNanoAccessors()
+        .setOptionalInt32(5)
+        .setOptionalString("Hello")
+        .setOptionalBytes(new byte[] {1, 2, 3})
+        .setOptionalNestedEnum(TestNanoAccessors.BAR);
+    message.optionalNestedMessage = new TestNanoAccessors.NestedMessage().setBb(27);
+    message.repeatedInt32 = new int[] { 5, 6, 7, 8 };
+    message.repeatedString = new String[] { "One", "Two" };
+    message.repeatedBytes = new byte[][] { { 2, 7 }, { 2, 7 } };
+    message.repeatedNestedMessage = new TestNanoAccessors.NestedMessage[] {
+      message.optionalNestedMessage,
+      message.optionalNestedMessage
+    };
+    message.repeatedNestedEnum = new int[] {
+      TestAllTypesNano.BAR,
+      TestAllTypesNano.BAZ
+    };
+    return message;
+  }
+
+  private NanoReferenceTypes.TestAllTypesNano createRefTypedMessageForHashCodeEqualsTest() {
+    NanoReferenceTypes.TestAllTypesNano message = new NanoReferenceTypes.TestAllTypesNano();
+    message.optionalInt32 = 5;
+    message.optionalInt64 = 777L;
+    message.optionalFloat = 1.0f;
+    message.optionalDouble = 2.0;
+    message.optionalBool = true;
+    message.optionalString = "Hello";
+    message.optionalBytes = new byte[] { 1, 2, 3 };
+    message.optionalNestedMessage =
+        new NanoReferenceTypes.TestAllTypesNano.NestedMessage();
+    message.optionalNestedMessage.foo = 27;
+    message.optionalNestedEnum = NanoReferenceTypes.TestAllTypesNano.BAR;
+    message.repeatedInt32 = new int[] { 5, 6, 7, 8 };
+    message.repeatedInt64 = new long[] { 27L, 28L, 29L };
+    message.repeatedFloat = new float[] { 5.0f, 6.0f };
+    message.repeatedDouble = new double[] { 99.1, 22.5 };
+    message.repeatedBool = new boolean[] { true, false, true };
+    message.repeatedString = new String[] { "One", "Two" };
+    message.repeatedBytes = new byte[][] { { 2, 7 }, { 2, 7 } };
+    message.repeatedNestedMessage =
+        new NanoReferenceTypes.TestAllTypesNano.NestedMessage[] {
+          message.optionalNestedMessage,
+          message.optionalNestedMessage
+        };
+    message.repeatedNestedEnum = new int[] {
+      NanoReferenceTypes.TestAllTypesNano.BAR,
+      NanoReferenceTypes.TestAllTypesNano.BAZ
+    };
+    return message;
+  }
+
+  public void testEqualsWithSpecialFloatingPointValues() throws Exception {
+    // Checks that the nano implementation complies with Object.equals() when treating
+    // floating point numbers, i.e. NaN == NaN and +0.0 != -0.0.
+    // This test assumes that the generated equals() implementations are symmetric, so
+    // there will only be one direction for each equality check.
+
+    TestAllTypesNano m1 = new TestAllTypesNano();
+    m1.optionalFloat = Float.NaN;
+    m1.optionalDouble = Double.NaN;
+    TestAllTypesNano m2 = new TestAllTypesNano();
+    m2.optionalFloat = Float.NaN;
+    m2.optionalDouble = Double.NaN;
+    assertTrue(m1.equals(m2));
+    assertTrue(m1.equals(
+        MessageNano.mergeFrom(new TestAllTypesNano(), MessageNano.toByteArray(m1))));
+
+    m1.optionalFloat = +0f;
+    m2.optionalFloat = -0f;
+    assertFalse(m1.equals(m2));
+
+    m1.optionalFloat = -0f;
+    m1.optionalDouble = +0d;
+    m2.optionalDouble = -0d;
+    assertFalse(m1.equals(m2));
+
+    m1.optionalDouble = -0d;
+    assertTrue(m1.equals(m2));
+    assertFalse(m1.equals(new TestAllTypesNano())); // -0 does not equals() the default +0
+    assertTrue(m1.equals(
+        MessageNano.mergeFrom(new TestAllTypesNano(), MessageNano.toByteArray(m1))));
+
+    // -------
+
+    TestAllTypesNanoHas m3 = new TestAllTypesNanoHas();
+    m3.optionalFloat = Float.NaN;
+    m3.hasOptionalFloat = true;
+    m3.optionalDouble = Double.NaN;
+    m3.hasOptionalDouble = true;
+    TestAllTypesNanoHas m4 = new TestAllTypesNanoHas();
+    m4.optionalFloat = Float.NaN;
+    m4.hasOptionalFloat = true;
+    m4.optionalDouble = Double.NaN;
+    m4.hasOptionalDouble = true;
+    assertTrue(m3.equals(m4));
+    assertTrue(m3.equals(
+        MessageNano.mergeFrom(new TestAllTypesNanoHas(), MessageNano.toByteArray(m3))));
+
+    m3.optionalFloat = +0f;
+    m4.optionalFloat = -0f;
+    assertFalse(m3.equals(m4));
+
+    m3.optionalFloat = -0f;
+    m3.optionalDouble = +0d;
+    m4.optionalDouble = -0d;
+    assertFalse(m3.equals(m4));
+
+    m3.optionalDouble = -0d;
+    m3.hasOptionalFloat = false;  // -0 does not equals() the default +0,
+    m3.hasOptionalDouble = false; // so these incorrect 'has' flags should be disregarded.
+    assertTrue(m3.equals(m4));    // note: m4 has the 'has' flags set.
+    assertFalse(m3.equals(new TestAllTypesNanoHas())); // note: the new message has +0 defaults
+    assertTrue(m3.equals(
+        MessageNano.mergeFrom(new TestAllTypesNanoHas(), MessageNano.toByteArray(m3))));
+                                  // note: the deserialized message has the 'has' flags set.
+
+    // -------
+
+    TestNanoAccessors m5 = new TestNanoAccessors();
+    m5.setOptionalFloat(Float.NaN);
+    m5.setOptionalDouble(Double.NaN);
+    TestNanoAccessors m6 = new TestNanoAccessors();
+    m6.setOptionalFloat(Float.NaN);
+    m6.setOptionalDouble(Double.NaN);
+    assertTrue(m5.equals(m6));
+    assertTrue(m5.equals(
+        MessageNano.mergeFrom(new TestNanoAccessors(), MessageNano.toByteArray(m6))));
+
+    m5.setOptionalFloat(+0f);
+    m6.setOptionalFloat(-0f);
+    assertFalse(m5.equals(m6));
+
+    m5.setOptionalFloat(-0f);
+    m5.setOptionalDouble(+0d);
+    m6.setOptionalDouble(-0d);
+    assertFalse(m5.equals(m6));
+
+    m5.setOptionalDouble(-0d);
+    assertTrue(m5.equals(m6));
+    assertFalse(m5.equals(new TestNanoAccessors()));
+    assertTrue(m5.equals(
+        MessageNano.mergeFrom(new TestNanoAccessors(), MessageNano.toByteArray(m6))));
+
+    // -------
+
+    NanoReferenceTypes.TestAllTypesNano m7 = new NanoReferenceTypes.TestAllTypesNano();
+    m7.optionalFloat = Float.NaN;
+    m7.optionalDouble = Double.NaN;
+    NanoReferenceTypes.TestAllTypesNano m8 = new NanoReferenceTypes.TestAllTypesNano();
+    m8.optionalFloat = Float.NaN;
+    m8.optionalDouble = Double.NaN;
+    assertTrue(m7.equals(m8));
+    assertTrue(m7.equals(MessageNano.mergeFrom(
+        new NanoReferenceTypes.TestAllTypesNano(), MessageNano.toByteArray(m7))));
+
+    m7.optionalFloat = +0f;
+    m8.optionalFloat = -0f;
+    assertFalse(m7.equals(m8));
+
+    m7.optionalFloat = -0f;
+    m7.optionalDouble = +0d;
+    m8.optionalDouble = -0d;
+    assertFalse(m7.equals(m8));
+
+    m7.optionalDouble = -0d;
+    assertTrue(m7.equals(m8));
+    assertFalse(m7.equals(new NanoReferenceTypes.TestAllTypesNano()));
+    assertTrue(m7.equals(MessageNano.mergeFrom(
+        new NanoReferenceTypes.TestAllTypesNano(), MessageNano.toByteArray(m7))));
+  }
+
+  public void testNullRepeatedFields() throws Exception {
+    // Check that serialization after explicitly setting a repeated field
+    // to null doesn't NPE.
+    TestAllTypesNano message = new TestAllTypesNano();
+    message.repeatedInt32 = null;
+    MessageNano.toByteArray(message);  // should not NPE
+    message.toString(); // should not NPE
+
+    message.repeatedNestedEnum = null;
+    MessageNano.toByteArray(message);  // should not NPE
+    message.toString(); // should not NPE
+
+    message.repeatedBytes = null;
+    MessageNano.toByteArray(message); // should not NPE
+    message.toString(); // should not NPE
+
+    message.repeatedNestedMessage = null;
+    MessageNano.toByteArray(message); // should not NPE
+    message.toString(); // should not NPE
+
+    message.repeatedPackedInt32 = null;
+    MessageNano.toByteArray(message); // should not NPE
+    message.toString(); // should not NPE
+
+    message.repeatedPackedNestedEnum = null;
+    MessageNano.toByteArray(message); // should not NPE
+    message.toString(); // should not NPE
+
+    // Create a second message to merge into message.
+    TestAllTypesNano secondMessage = new TestAllTypesNano();
+    secondMessage.repeatedInt32 = new int[] {1, 2, 3};
+    secondMessage.repeatedNestedEnum = new int[] {
+      TestAllTypesNano.FOO, TestAllTypesNano.BAR
+    };
+    secondMessage.repeatedBytes = new byte[][] {{1, 2}, {3, 4}};
+    TestAllTypesNano.NestedMessage nested =
+        new TestAllTypesNano.NestedMessage();
+    nested.bb = 55;
+    secondMessage.repeatedNestedMessage =
+        new TestAllTypesNano.NestedMessage[] {nested};
+    secondMessage.repeatedPackedInt32 = new int[] {1, 2, 3};
+    secondMessage.repeatedPackedNestedEnum = new int[] {
+        TestAllTypesNano.FOO, TestAllTypesNano.BAR
+      };
+
+    // Should not NPE
+    message.mergeFrom(CodedInputByteBufferNano.newInstance(
+        MessageNano.toByteArray(secondMessage)));
+    assertEquals(3, message.repeatedInt32.length);
+    assertEquals(3, message.repeatedInt32[2]);
+    assertEquals(2, message.repeatedNestedEnum.length);
+    assertEquals(TestAllTypesNano.FOO, message.repeatedNestedEnum[0]);
+    assertEquals(2, message.repeatedBytes.length);
+    assertEquals(4, message.repeatedBytes[1][1]);
+    assertEquals(1, message.repeatedNestedMessage.length);
+    assertEquals(55, message.repeatedNestedMessage[0].bb);
+    assertEquals(3, message.repeatedPackedInt32.length);
+    assertEquals(2, message.repeatedPackedInt32[1]);
+    assertEquals(2, message.repeatedPackedNestedEnum.length);
+    assertEquals(TestAllTypesNano.BAR, message.repeatedPackedNestedEnum[1]);
+  }
+
+  public void testNullRepeatedFieldElements() throws Exception {
+    // Check that serialization with null array elements doesn't NPE.
+    String string1 = "1";
+    String string2 = "2";
+    byte[] bytes1 = {3, 4};
+    byte[] bytes2 = {5, 6};
+    TestAllTypesNano.NestedMessage msg1 = new TestAllTypesNano.NestedMessage();
+    msg1.bb = 7;
+    TestAllTypesNano.NestedMessage msg2 = new TestAllTypesNano.NestedMessage();
+    msg2.bb = 8;
+
+    TestAllTypesNano message = new TestAllTypesNano();
+    message.repeatedString = new String[] {null, string1, string2};
+    message.repeatedBytes = new byte[][] {bytes1, null, bytes2};
+    message.repeatedNestedMessage = new TestAllTypesNano.NestedMessage[] {msg1, msg2, null};
+    message.repeatedGroup = new TestAllTypesNano.RepeatedGroup[] {null, null, null};
+
+    byte[] serialized = MessageNano.toByteArray(message); // should not NPE
+    TestAllTypesNano deserialized = MessageNano.mergeFrom(new TestAllTypesNano(), serialized);
+    assertEquals(2, deserialized.repeatedString.length);
+    assertEquals(string1, deserialized.repeatedString[0]);
+    assertEquals(string2, deserialized.repeatedString[1]);
+    assertEquals(2, deserialized.repeatedBytes.length);
+    assertTrue(Arrays.equals(bytes1, deserialized.repeatedBytes[0]));
+    assertTrue(Arrays.equals(bytes2, deserialized.repeatedBytes[1]));
+    assertEquals(2, deserialized.repeatedNestedMessage.length);
+    assertEquals(msg1.bb, deserialized.repeatedNestedMessage[0].bb);
+    assertEquals(msg2.bb, deserialized.repeatedNestedMessage[1].bb);
+    assertEquals(0, deserialized.repeatedGroup.length);
+  }
+
+  public void testRepeatedMerge() throws Exception {
+    // Check that merging repeated fields cause the arrays to expand with
+    // new data.
+    TestAllTypesNano first = new TestAllTypesNano();
+    first.repeatedInt32 = new int[] {1, 2, 3};
+    TestAllTypesNano second = new TestAllTypesNano();
+    second.repeatedInt32 = new int[] {4, 5};
+    MessageNano.mergeFrom(first, MessageNano.toByteArray(second));
+    assertEquals(5, first.repeatedInt32.length);
+    assertEquals(1, first.repeatedInt32[0]);
+    assertEquals(4, first.repeatedInt32[3]);
+
+    first = new TestAllTypesNano();
+    first.repeatedNestedEnum = new int[] {TestAllTypesNano.BAR};
+    second = new TestAllTypesNano();
+    second.repeatedNestedEnum = new int[] {TestAllTypesNano.FOO};
+    MessageNano.mergeFrom(first, MessageNano.toByteArray(second));
+    assertEquals(2, first.repeatedNestedEnum.length);
+    assertEquals(TestAllTypesNano.BAR, first.repeatedNestedEnum[0]);
+    assertEquals(TestAllTypesNano.FOO, first.repeatedNestedEnum[1]);
+
+    first = new TestAllTypesNano();
+    first.repeatedNestedMessage = new TestAllTypesNano.NestedMessage[] {
+      new TestAllTypesNano.NestedMessage()
+    };
+    first.repeatedNestedMessage[0].bb = 3;
+    second = new TestAllTypesNano();
+    second.repeatedNestedMessage = new TestAllTypesNano.NestedMessage[] {
+      new TestAllTypesNano.NestedMessage()
+    };
+    second.repeatedNestedMessage[0].bb = 5;
+    MessageNano.mergeFrom(first, MessageNano.toByteArray(second));
+    assertEquals(2, first.repeatedNestedMessage.length);
+    assertEquals(3, first.repeatedNestedMessage[0].bb);
+    assertEquals(5, first.repeatedNestedMessage[1].bb);
+
+    first = new TestAllTypesNano();
+    first.repeatedPackedSfixed64 = new long[] {-1, -2, -3};
+    second = new TestAllTypesNano();
+    second.repeatedPackedSfixed64 = new long[] {-4, -5};
+    MessageNano.mergeFrom(first, MessageNano.toByteArray(second));
+    assertEquals(5, first.repeatedPackedSfixed64.length);
+    assertEquals(-1, first.repeatedPackedSfixed64[0]);
+    assertEquals(-4, first.repeatedPackedSfixed64[3]);
+
+    first = new TestAllTypesNano();
+    first.repeatedPackedNestedEnum = new int[] {TestAllTypesNano.BAR};
+    second = new TestAllTypesNano();
+    second.repeatedPackedNestedEnum = new int[] {TestAllTypesNano.FOO};
+    MessageNano.mergeFrom(first, MessageNano.toByteArray(second));
+    assertEquals(2, first.repeatedPackedNestedEnum.length);
+    assertEquals(TestAllTypesNano.BAR, first.repeatedPackedNestedEnum[0]);
+    assertEquals(TestAllTypesNano.FOO, first.repeatedPackedNestedEnum[1]);
+
+    // Now test repeated merging in a nested scope
+    TestRepeatedMergeNano firstContainer = new TestRepeatedMergeNano();
+    firstContainer.contained = new TestAllTypesNano();
+    firstContainer.contained.repeatedInt32 = new int[] {10, 20};
+    TestRepeatedMergeNano secondContainer = new TestRepeatedMergeNano();
+    secondContainer.contained = new TestAllTypesNano();
+    secondContainer.contained.repeatedInt32 = new int[] {30};
+    MessageNano.mergeFrom(firstContainer, MessageNano.toByteArray(secondContainer));
+    assertEquals(3, firstContainer.contained.repeatedInt32.length);
+    assertEquals(20, firstContainer.contained.repeatedInt32[1]);
+    assertEquals(30, firstContainer.contained.repeatedInt32[2]);
+  }
+
+  public void testRepeatedPackables() throws Exception {
+    // Check that repeated fields with packable types can accept both packed and unpacked
+    // serialized forms.
+    NanoRepeatedPackables.NonPacked nonPacked = new NanoRepeatedPackables.NonPacked();
+    // Exaggerates the first values of varint-typed arrays. This is to test that the parsing code
+    // of packed fields handles non-packed data correctly. If the code incorrectly thinks it is
+    // reading from a packed tag, it will read the first value as the byte length of the field,
+    // and the large number will cause the input to go out of bounds, thus capturing the error.
+    nonPacked.int32S = new int[] {1000, 2, 3};
+    nonPacked.int64S = new long[] {4000, 5, 6};
+    nonPacked.uint32S = new int[] {7000, 8, 9};
+    nonPacked.uint64S = new long[] {10000, 11, 12};
+    nonPacked.sint32S = new int[] {13000, 14, 15};
+    nonPacked.sint64S = new long[] {16000, 17, 18};
+    nonPacked.fixed32S = new int[] {19, 20, 21};
+    nonPacked.fixed64S = new long[] {22, 23, 24};
+    nonPacked.sfixed32S = new int[] {25, 26, 27};
+    nonPacked.sfixed64S = new long[] {28, 29, 30};
+    nonPacked.floats = new float[] {31, 32, 33};
+    nonPacked.doubles = new double[] {34, 35, 36};
+    nonPacked.bools = new boolean[] {false, true};
+    nonPacked.enums = new int[] {
+      NanoRepeatedPackables.Enum.OPTION_ONE,
+      NanoRepeatedPackables.Enum.OPTION_TWO,
+    };
+    nonPacked.noise = 13579;
+
+    byte[] nonPackedSerialized = MessageNano.toByteArray(nonPacked);
+
+    NanoRepeatedPackables.Packed packed =
+        MessageNano.mergeFrom(new NanoRepeatedPackables.Packed(), nonPackedSerialized);
+    assertRepeatedPackablesEqual(nonPacked, packed);
+
+    byte[] packedSerialized = MessageNano.toByteArray(packed);
+    // Just a cautious check that the two serialized forms are different,
+    // to make sure the remaining of this test is useful:
+    assertFalse(Arrays.equals(nonPackedSerialized, packedSerialized));
+
+    nonPacked = MessageNano.mergeFrom(new NanoRepeatedPackables.NonPacked(), packedSerialized);
+    assertRepeatedPackablesEqual(nonPacked, packed);
+
+    // Test mixed serialized form.
+    byte[] mixedSerialized = new byte[nonPackedSerialized.length + packedSerialized.length];
+    System.arraycopy(nonPackedSerialized, 0, mixedSerialized, 0, nonPackedSerialized.length);
+    System.arraycopy(packedSerialized, 0,
+        mixedSerialized, nonPackedSerialized.length, packedSerialized.length);
+
+    nonPacked = MessageNano.mergeFrom(new NanoRepeatedPackables.NonPacked(), mixedSerialized);
+    packed = MessageNano.mergeFrom(new NanoRepeatedPackables.Packed(), mixedSerialized);
+    assertRepeatedPackablesEqual(nonPacked, packed);
+    assertTrue(Arrays.equals(new int[] {1000, 2, 3, 1000, 2, 3}, nonPacked.int32S));
+    assertTrue(Arrays.equals(new int[] {13000, 14, 15, 13000, 14, 15}, nonPacked.sint32S));
+    assertTrue(Arrays.equals(new int[] {25, 26, 27, 25, 26, 27}, nonPacked.sfixed32S));
+    assertTrue(Arrays.equals(new boolean[] {false, true, false, true}, nonPacked.bools));
+  }
+
+  private void assertRepeatedPackablesEqual(
+      NanoRepeatedPackables.NonPacked nonPacked, NanoRepeatedPackables.Packed packed) {
+    // Not using MessageNano.equals() -- that belongs to a separate test.
+    assertTrue(Arrays.equals(nonPacked.int32S, packed.int32S));
+    assertTrue(Arrays.equals(nonPacked.int64S, packed.int64S));
+    assertTrue(Arrays.equals(nonPacked.uint32S, packed.uint32S));
+    assertTrue(Arrays.equals(nonPacked.uint64S, packed.uint64S));
+    assertTrue(Arrays.equals(nonPacked.sint32S, packed.sint32S));
+    assertTrue(Arrays.equals(nonPacked.sint64S, packed.sint64S));
+    assertTrue(Arrays.equals(nonPacked.fixed32S, packed.fixed32S));
+    assertTrue(Arrays.equals(nonPacked.fixed64S, packed.fixed64S));
+    assertTrue(Arrays.equals(nonPacked.sfixed32S, packed.sfixed32S));
+    assertTrue(Arrays.equals(nonPacked.sfixed64S, packed.sfixed64S));
+    assertTrue(Arrays.equals(nonPacked.floats, packed.floats));
+    assertTrue(Arrays.equals(nonPacked.doubles, packed.doubles));
+    assertTrue(Arrays.equals(nonPacked.bools, packed.bools));
+    assertTrue(Arrays.equals(nonPacked.enums, packed.enums));
+  }
+
+  private void assertHasWireData(MessageNano message, boolean expected) {
+    byte[] bytes = MessageNano.toByteArray(message);
+    int wireLength = bytes.length;
+    if (expected) {
+      assertFalse(wireLength == 0);
+    } else {
+      if (wireLength != 0) {
+        fail("Expected no wire data for message \n" + message
+            + "\nBut got:\n"
+            + hexDump(bytes));
+      }
+    }
+  }
+
+  private static String hexDump(byte[] bytes) {
+    StringBuilder sb = new StringBuilder();
+    for (byte b : bytes) {
+      sb.append(String.format("%02x ", b));
+    }
+    return sb.toString();
+  }
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_accessors_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_accessors_nano.proto
new file mode 100644
index 00000000..f1d4d343
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_accessors_nano.proto
@@ -0,0 +1,118 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: maxtroy@google.com (Max Cai)
+
+package protobuf_unittest;
+
+option java_package = "com.google.protobuf.nano";
+option java_outer_classname = "NanoAccessorsOuterClass";
+
+message TestNanoAccessors {
+
+  message NestedMessage {
+    optional int32 bb = 1;
+  }
+
+  enum NestedEnum {
+    FOO = 1;
+    BAR = 2;
+    BAZ = 3;
+  }
+
+  // Singular
+  optional int32  optional_int32    =  1;
+  optional float  optional_float    = 11;
+  optional double optional_double   = 12;
+  optional string optional_string   = 14;
+  optional bytes  optional_bytes    = 15;
+
+  optional NestedMessage optional_nested_message = 18;
+
+  optional NestedEnum optional_nested_enum = 21;
+
+  // Repeated
+  repeated int32  repeated_int32    = 31;
+  repeated string repeated_string   = 44;
+  repeated bytes  repeated_bytes    = 45;
+
+  repeated NestedMessage repeated_nested_message  = 48;
+
+  repeated NestedEnum repeated_nested_enum  = 51;
+
+  // Singular with defaults
+  optional int32  default_int32    = 61 [default =  41    ];
+  optional string default_string   = 74 [default = "hello"];
+  optional bytes  default_bytes    = 75 [default = "world"];
+
+  optional float default_float_nan = 99  [default =  nan];
+
+  optional NestedEnum default_nested_enum = 81 [default = BAR];
+
+  // Required
+  required int32 id = 86;
+
+  // Add enough optional fields to make 2 bit fields in total
+  optional int32 filler100 = 100;
+  optional int32 filler101 = 101;
+  optional int32 filler102 = 102;
+  optional int32 filler103 = 103;
+  optional int32 filler104 = 104;
+  optional int32 filler105 = 105;
+  optional int32 filler106 = 106;
+  optional int32 filler107 = 107;
+  optional int32 filler108 = 108;
+  optional int32 filler109 = 109;
+  optional int32 filler110 = 110;
+  optional int32 filler111 = 111;
+  optional int32 filler112 = 112;
+  optional int32 filler113 = 113;
+  optional int32 filler114 = 114;
+  optional int32 filler115 = 115;
+  optional int32 filler116 = 116;
+  optional int32 filler117 = 117;
+  optional int32 filler118 = 118;
+  optional int32 filler119 = 119;
+  optional int32 filler120 = 120;
+  optional int32 filler121 = 121;
+  optional int32 filler122 = 122;
+  optional int32 filler123 = 123;
+  optional int32 filler124 = 124;
+  optional int32 filler125 = 125;
+  optional int32 filler126 = 126;
+  optional int32 filler127 = 127;
+  optional int32 filler128 = 128;
+  optional int32 filler129 = 129;
+  optional int32 filler130 = 130;
+
+  optional int32 before_bit_field_check = 139;
+  optional int32 bit_field_check = 140;
+  optional int32 after_bit_field_check = 141;
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_enum_class_multiple_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_enum_class_multiple_nano.proto
new file mode 100644
index 00000000..8adb7560
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_enum_class_multiple_nano.proto
@@ -0,0 +1,48 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: maxtroy@google.com (Max Cai)
+
+package protobuf_unittest;
+
+option java_package = "com.google.protobuf.nano";
+option java_multiple_files = true;
+
+enum FileScopeEnumMultiple {
+  THREE = 3;
+}
+
+message EnumClassNanoMultiple {
+  enum MessageScopeEnumMultiple {
+    FOUR = 4;
+  }
+  optional FileScopeEnumMultiple three = 3 [ default = THREE ];
+  optional MessageScopeEnumMultiple four = 4 [ default = FOUR ];
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_enum_class_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_enum_class_nano.proto
new file mode 100644
index 00000000..3727d68d
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_enum_class_nano.proto
@@ -0,0 +1,48 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: maxtroy@google.com (Max Cai)
+
+package protobuf_unittest;
+
+option java_package = "com.google.protobuf.nano";
+option java_outer_classname = "EnumClassNanos";
+
+enum FileScopeEnum {
+  ONE = 1;
+}
+
+message EnumClassNano {
+  enum MessageScopeEnum {
+    TWO = 2;
+  }
+  optional FileScopeEnum one = 1 [ default = ONE ];
+  optional MessageScopeEnum two = 2 [ default = TWO ];
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_enum_validity_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_enum_validity_nano.proto
new file mode 100644
index 00000000..f7f57427
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_enum_validity_nano.proto
@@ -0,0 +1,28 @@
+package protobuf_unittest;
+
+option java_package = "com.google.protobuf.nano";
+option java_outer_classname = "EnumValidity";
+
+enum E {
+  default = 1; // test java keyword renaming
+  FOO = 2;
+  BAR = 3;
+  BAZ = 4;
+}
+
+message M {
+  optional E optional_e = 1;
+  optional E default_e = 2 [ default = BAZ ];
+  repeated E repeated_e = 3;
+  repeated E packed_e = 4 [ packed = true ];
+  repeated E repeated_e2 = 5;
+  repeated E packed_e2 = 6 [ packed = true ];
+  repeated E repeated_e3 = 7;
+  repeated E packed_e3 = 8 [ packed = true ];
+}
+
+message Alt {
+  optional E repeated_e2_as_optional = 5;
+  repeated E packed_e2_as_non_packed = 6;
+  repeated E non_packed_e3_as_packed = 7 [ packed = true ];
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_nano.proto
new file mode 100644
index 00000000..2a678a80
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_nano.proto
@@ -0,0 +1,33 @@
+syntax = "proto2";
+
+option java_outer_classname = "Extensions";
+option java_package = "com.google.protobuf.nano.testext";
+
+message ExtendableMessage {
+  optional int32 field = 1;
+  extensions 10 to max;
+}
+
+enum AnEnum {
+  FIRST_VALUE = 1;
+  SECOND_VALUE = 2;
+}
+
+message AnotherMessage {
+  optional string string = 1;
+  optional bool value = 2;
+}
+
+message ContainerMessage {
+  extend ExtendableMessage {
+    optional bool another_thing = 100;
+  }
+}
+
+// For testNanoOptionalGroupWithUnknownFieldsEnabled;
+// not part of the extensions tests.
+message MessageWithGroup {
+  optional group Group = 1 {
+    optional int32 a = 2;
+  }
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_packed_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_packed_nano.proto
new file mode 100644
index 00000000..7d47682d
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_packed_nano.proto
@@ -0,0 +1,29 @@
+syntax = "proto2";
+
+option java_multiple_files = true;
+option java_package = "com.google.protobuf.nano";
+
+import "google/protobuf/nano/unittest_extension_nano.proto";
+
+// Must be compiled separately due to extension number reuse.
+// The reuse is deliberate, for testing wire compatibility.
+
+message PackedExtensions {
+  extend ExtendableMessage {
+    repeated int32    packed_int32    = 10 [ packed = true ];
+    repeated uint32   packed_uint32   = 11 [ packed = true ];
+    repeated sint32   packed_sint32   = 12 [ packed = true ];
+    repeated int64    packed_int64    = 13 [ packed = true ];
+    repeated uint64   packed_uint64   = 14 [ packed = true ];
+    repeated sint64   packed_sint64   = 15 [ packed = true ];
+    repeated fixed32  packed_fixed32  = 16 [ packed = true ];
+    repeated sfixed32 packed_sfixed32 = 17 [ packed = true ];
+    repeated fixed64  packed_fixed64  = 18 [ packed = true ];
+    repeated sfixed64 packed_sfixed64 = 19 [ packed = true ];
+    repeated bool     packed_bool     = 20 [ packed = true ];
+    repeated float    packed_float    = 21 [ packed = true ];
+    repeated double   packed_double   = 22 [ packed = true ];
+    repeated AnEnum   packed_enum     = 23 [ packed = true ];
+    // Non-packable types omitted.
+  }
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_repeated_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_repeated_nano.proto
new file mode 100644
index 00000000..6d4b5dfb
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_repeated_nano.proto
@@ -0,0 +1,34 @@
+syntax = "proto2";
+
+option java_multiple_files = true;
+option java_package = "com.google.protobuf.nano";
+
+import "google/protobuf/nano/unittest_extension_nano.proto";
+
+// Must be compiled separately due to extension number reuse.
+// The reuse is deliberate, for testing wire compatibility.
+
+message RepeatedExtensions {
+  extend ExtendableMessage {
+    repeated int32          repeated_int32    = 10;
+    repeated uint32         repeated_uint32   = 11;
+    repeated sint32         repeated_sint32   = 12;
+    repeated int64          repeated_int64    = 13;
+    repeated uint64         repeated_uint64   = 14;
+    repeated sint64         repeated_sint64   = 15;
+    repeated fixed32        repeated_fixed32  = 16;
+    repeated sfixed32       repeated_sfixed32 = 17;
+    repeated fixed64        repeated_fixed64  = 18;
+    repeated sfixed64       repeated_sfixed64 = 19;
+    repeated bool           repeated_bool     = 20;
+    repeated float          repeated_float    = 21;
+    repeated double         repeated_double   = 22;
+    repeated AnEnum         repeated_enum     = 23;
+    repeated string         repeated_string   = 24;
+    repeated bytes          repeated_bytes    = 25;
+    repeated AnotherMessage repeated_message  = 26;
+    repeated group          RepeatedGroup     = 27 {
+      optional int32 a = 1;
+    }
+  }
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_singular_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_singular_nano.proto
new file mode 100644
index 00000000..589754e7
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_singular_nano.proto
@@ -0,0 +1,34 @@
+syntax = "proto2";
+
+option java_multiple_files = true;
+option java_package = "com.google.protobuf.nano";
+
+import "google/protobuf/nano/unittest_extension_nano.proto";
+
+// Must be compiled separately due to extension number reuse.
+// The reuse is deliberate, for testing wire compatibility.
+
+message SingularExtensions {
+  extend ExtendableMessage {
+    optional int32          some_int32    = 10;
+    optional uint32         some_uint32   = 11;
+    optional sint32         some_sint32   = 12;
+    optional int64          some_int64    = 13;
+    optional uint64         some_uint64   = 14;
+    optional sint64         some_sint64   = 15;
+    optional fixed32        some_fixed32  = 16;
+    optional sfixed32       some_sfixed32 = 17;
+    optional fixed64        some_fixed64  = 18;
+    optional sfixed64       some_sfixed64 = 19;
+    optional bool           some_bool     = 20;
+    optional float          some_float    = 21;
+    optional double         some_double   = 22;
+    optional AnEnum         some_enum     = 23;
+    optional string         some_string   = 24;
+    optional bytes          some_bytes    = 25;
+    optional AnotherMessage some_message  = 26;
+    optional group          SomeGroup     = 27 {
+      optional int32 a = 1;
+    }
+  }
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_has_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_has_nano.proto
new file mode 100644
index 00000000..289d08ae
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_has_nano.proto
@@ -0,0 +1,82 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: ulas@google.com (Ulas Kirazci)
+
+package protobuf_unittest;
+
+option java_package = "com.google.protobuf.nano";
+option java_outer_classname = "NanoHasOuterClass";
+
+message TestAllTypesNanoHas {
+
+  message NestedMessage {
+    optional int32 bb = 1;
+  }
+
+  enum NestedEnum {
+    FOO = 1;
+    BAR = 2;
+    BAZ = 3;
+  }
+
+  // Singular
+  optional int32  optional_int32    =  1;
+  optional float  optional_float    = 11;
+  optional double optional_double   = 12;
+  optional string optional_string   = 14;
+  optional bytes  optional_bytes    = 15;
+
+  optional NestedMessage optional_nested_message = 18;
+
+  optional NestedEnum optional_nested_enum = 21;
+
+  // Repeated
+  repeated int32  repeated_int32    = 31;
+  repeated string repeated_string   = 44;
+  repeated bytes  repeated_bytes    = 45;
+
+  repeated NestedMessage repeated_nested_message  = 48;
+
+  repeated NestedEnum repeated_nested_enum  = 51;
+
+  // Singular with defaults
+  optional int32  default_int32    = 61 [default =  41    ];
+  optional string default_string   = 74 [default = "hello"];
+  optional bytes  default_bytes    = 75 [default = "world"];
+
+  optional float default_float_nan = 99  [default =  nan];
+
+  optional NestedEnum default_nested_enum = 81 [default = BAR];
+
+  required int32 id = 86;
+  required NestedEnum required_enum = 87;
+
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_import_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_import_nano.proto
new file mode 100644
index 00000000..bcd4db7b
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_import_nano.proto
@@ -0,0 +1,48 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: kenton@google.com (Kenton Varda)
+//
+// This is like unittest_import.proto but with optimize_for = NANO_RUNTIME.
+
+package protobuf_unittest_import;
+
+option java_package = "com.google.protobuf.nano.testimport";
+option java_outer_classname = "UnittestImportNano";
+
+message ImportMessageNano {
+  optional int32 d = 1;
+}
+
+enum ImportEnumNano {
+  IMPORT_NANO_FOO = 7;
+  IMPORT_NANO_BAR = 8;
+  IMPORT_NANO_BAZ = 9;
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_multiple_nameclash_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_multiple_nameclash_nano.proto
new file mode 100644
index 00000000..f2f62c4e
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_multiple_nameclash_nano.proto
@@ -0,0 +1,41 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: maxtroy@google.com (Max Cai)
+
+package protobuf_unittest_import;
+
+option java_package = "com.google.protobuf.nano";
+option java_outer_classname = "MultipleNameClashNano";
+option java_multiple_files = true;
+
+message MultipleNameClashNano {
+  optional int32 field = 1;
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_multiple_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_multiple_nano.proto
new file mode 100644
index 00000000..be84cad1
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_multiple_nano.proto
@@ -0,0 +1,63 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: maxtroy@google.com (Max Cai)
+
+package protobuf_unittest_import;
+
+import "google/protobuf/nano/unittest_import_nano.proto";
+
+option java_package = "com.google.protobuf.nano";
+option java_multiple_files = true;
+
+enum FileScopeEnum {
+  ONE = 1;
+  TWO = 2;
+}
+
+message FileScopeEnumRefNano {
+  optional FileScopeEnum enum_field = 1;
+}
+
+message MessageScopeEnumRefNano {
+  enum MessageScopeEnum {
+    ONE = 1;
+    TWO = 2;
+  }
+  optional MessageScopeEnum enum_field = 1;
+}
+
+message MultipleImportingNonMultipleNano1 {
+  optional ImportMessageNano field = 1;
+}
+
+message MultipleImportingNonMultipleNano2 {
+  optional MultipleImportingNonMultipleNano1 nano1 = 1;
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_nano.proto
new file mode 100644
index 00000000..cba52c02
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_nano.proto
@@ -0,0 +1,186 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: wink@google.com (Wink Saville)
+
+package protobuf_unittest;
+
+import "google/protobuf/nano/unittest_import_nano.proto";
+
+option java_package = "com.google.protobuf.nano";
+option java_outer_classname = "NanoOuterClass";
+
+// Same as TestAllTypes but with the nano runtime.
+message TestAllTypesNano {
+
+  message NestedMessage {
+    optional int32 bb = 1;
+  }
+
+  enum NestedEnum {
+    FOO = 1;
+    BAR = 2;
+    BAZ = 3;
+  }
+
+  // Singular
+  optional    int32 optional_int32    =  1;
+  optional    int64 optional_int64    =  2;
+  optional   uint32 optional_uint32   =  3;
+  optional   uint64 optional_uint64   =  4;
+  optional   sint32 optional_sint32   =  5;
+  optional   sint64 optional_sint64   =  6;
+  optional  fixed32 optional_fixed32  =  7;
+  optional  fixed64 optional_fixed64  =  8;
+  optional sfixed32 optional_sfixed32 =  9;
+  optional sfixed64 optional_sfixed64 = 10;
+  optional    float optional_float    = 11;
+  optional   double optional_double   = 12;
+  optional     bool optional_bool     = 13;
+  optional   string optional_string   = 14;
+  optional    bytes optional_bytes    = 15;
+
+  optional group OptionalGroup = 16 {
+    optional int32 a = 17;
+  }
+
+  optional NestedMessage      optional_nested_message  = 18;
+  optional ForeignMessageNano optional_foreign_message = 19;
+  optional protobuf_unittest_import.ImportMessageNano
+    optional_import_message = 20;
+
+  optional NestedEnum      optional_nested_enum     = 21;
+  optional ForeignEnumNano optional_foreign_enum    = 22;
+  optional protobuf_unittest_import.ImportEnumNano optional_import_enum = 23;
+
+  optional string optional_string_piece = 24 [ctype=STRING_PIECE];
+  optional string optional_cord = 25 [ctype=CORD];
+
+  // Repeated
+  repeated    int32 repeated_int32    = 31;
+  repeated    int64 repeated_int64    = 32;
+  repeated   uint32 repeated_uint32   = 33;
+  repeated   uint64 repeated_uint64   = 34;
+  repeated   sint32 repeated_sint32   = 35;
+  repeated   sint64 repeated_sint64   = 36;
+  repeated  fixed32 repeated_fixed32  = 37;
+  repeated  fixed64 repeated_fixed64  = 38;
+  repeated sfixed32 repeated_sfixed32 = 39;
+  repeated sfixed64 repeated_sfixed64 = 40;
+  repeated    float repeated_float    = 41;
+  repeated   double repeated_double   = 42;
+  repeated     bool repeated_bool     = 43;
+  repeated   string repeated_string   = 44;
+  repeated    bytes repeated_bytes    = 45;
+
+  repeated group RepeatedGroup = 46 {
+    optional int32 a = 47;
+  }
+
+  repeated NestedMessage      repeated_nested_message  = 48;
+  repeated ForeignMessageNano repeated_foreign_message = 49;
+  repeated protobuf_unittest_import.ImportMessageNano
+    repeated_import_message = 50;
+
+  repeated NestedEnum      repeated_nested_enum  = 51;
+  repeated ForeignEnumNano repeated_foreign_enum = 52;
+  repeated protobuf_unittest_import.ImportEnumNano repeated_import_enum = 53;
+
+  repeated string repeated_string_piece = 54 [ctype=STRING_PIECE];
+  repeated string repeated_cord = 55 [ctype=CORD];
+
+  // Repeated packed
+  repeated    int32 repeated_packed_int32    = 87 [packed=true];
+  repeated sfixed64 repeated_packed_sfixed64 = 88 [packed=true];
+
+  repeated NestedEnum repeated_packed_nested_enum  = 89 [packed=true];
+
+  // Singular with defaults
+  optional    int32 default_int32    = 61 [default =  41    ];
+  optional    int64 default_int64    = 62 [default =  42    ];
+  optional   uint32 default_uint32   = 63 [default =  43    ];
+  optional   uint64 default_uint64   = 64 [default =  44    ];
+  optional   sint32 default_sint32   = 65 [default = -45    ];
+  optional   sint64 default_sint64   = 66 [default =  46    ];
+  optional  fixed32 default_fixed32  = 67 [default =  47    ];
+  optional  fixed64 default_fixed64  = 68 [default =  48    ];
+  optional sfixed32 default_sfixed32 = 69 [default =  49    ];
+  optional sfixed64 default_sfixed64 = 70 [default = -50    ];
+  optional    float default_float    = 71 [default =  51.5  ];
+  optional   double default_double   = 72 [default =  52e3  ];
+  optional     bool default_bool     = 73 [default = true   ];
+  optional   string default_string   = 74 [default = "hello"];
+  optional    bytes default_bytes    = 75 [default = "world"];
+
+  optional string default_string_nonascii = 76 [default = "dünya"];
+  optional  bytes default_bytes_nonascii  = 77 [default = "dünyab"];
+
+  optional  float default_float_inf      = 97  [default =  inf];
+  optional  float default_float_neg_inf  = 98  [default = -inf];
+  optional  float default_float_nan      = 99  [default =  nan];
+  optional double default_double_inf     = 100 [default =  inf];
+  optional double default_double_neg_inf = 101 [default = -inf];
+  optional double default_double_nan     = 102 [default =  nan];
+
+  optional NestedEnum default_nested_enum = 81 [default = BAR];
+  optional ForeignEnumNano default_foreign_enum = 82
+      [default = FOREIGN_NANO_BAR];
+  optional protobuf_unittest_import.ImportEnumNano
+      default_import_enum = 83 [default = IMPORT_NANO_BAR];
+
+  optional string default_string_piece = 84 [ctype=STRING_PIECE,default="abc"];
+  optional string default_cord = 85 [ctype=CORD,default="123"];
+
+  required int32 id = 86;
+
+  // Try to cause conflicts.
+  optional int32 tag = 93;
+  optional int32 get_serialized_size = 94;
+  optional int32 write_to = 95;
+
+  // Try to fail with java reserved keywords
+  optional int32 synchronized = 96;
+}
+
+message ForeignMessageNano {
+  optional int32 c = 1;
+}
+
+enum ForeignEnumNano {
+  FOREIGN_NANO_FOO = 4;
+  FOREIGN_NANO_BAR = 5;
+  FOREIGN_NANO_BAZ = 6;
+}
+
+// Test that deprecated fields work.  We only verify that they compile (at one
+// point this failed).
+message TestDeprecatedNano {
+  optional int32 deprecated_field = 1 [deprecated = true];
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_recursive_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_recursive_nano.proto
new file mode 100644
index 00000000..3d3a6aa4
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_recursive_nano.proto
@@ -0,0 +1,49 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: wink@google.com (Wink Saville)
+//
+
+package protobuf_unittest_import;
+
+option java_package = "com.google.protobuf.nano";
+// Explicit outer classname to suppress legacy info.
+option java_outer_classname = "UnittestRecursiveNano";
+
+message RecursiveMessageNano {
+  message NestedMessage {
+    optional RecursiveMessageNano a = 1;
+  }
+
+  required int32 id = 1;
+  optional NestedMessage nested_message = 2;
+  optional RecursiveMessageNano optional_recursive_message_nano = 3;
+  repeated RecursiveMessageNano repeated_recursive_message_nano = 4;
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_reference_types_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_reference_types_nano.proto
new file mode 100644
index 00000000..2b246150
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_reference_types_nano.proto
@@ -0,0 +1,116 @@
+package protobuf_unittest;
+
+option java_package = "com.google.protobuf.nano";
+option java_outer_classname = "NanoReferenceTypes";
+
+message TestAllTypesNano {
+
+  enum NestedEnum {
+    FOO = 1;
+    BAR = 2;
+    BAZ = 3;
+  }
+
+  message NestedMessage {
+    optional int32 foo = 1;
+  }
+
+  // Singular
+  optional    int32 optional_int32    =  1;
+  optional    int64 optional_int64    =  2;
+  optional   uint32 optional_uint32   =  3;
+  optional   uint64 optional_uint64   =  4;
+  optional   sint32 optional_sint32   =  5;
+  optional   sint64 optional_sint64   =  6;
+  optional  fixed32 optional_fixed32  =  7;
+  optional  fixed64 optional_fixed64  =  8;
+  optional sfixed32 optional_sfixed32 =  9;
+  optional sfixed64 optional_sfixed64 = 10;
+  optional    float optional_float    = 11;
+  optional   double optional_double   = 12;
+  optional     bool optional_bool     = 13;
+  optional   string optional_string   = 14;
+  optional    bytes optional_bytes    = 15;
+
+  optional group OptionalGroup = 16 {
+    optional int32 a = 17;
+  }
+
+  optional NestedMessage      optional_nested_message  = 18;
+
+  optional NestedEnum      optional_nested_enum     = 21;
+
+  optional string optional_string_piece = 24 [ctype=STRING_PIECE];
+  optional string optional_cord = 25 [ctype=CORD];
+
+  // Repeated
+  repeated    int32 repeated_int32    = 31;
+  repeated    int64 repeated_int64    = 32;
+  repeated   uint32 repeated_uint32   = 33;
+  repeated   uint64 repeated_uint64   = 34;
+  repeated   sint32 repeated_sint32   = 35;
+  repeated   sint64 repeated_sint64   = 36;
+  repeated  fixed32 repeated_fixed32  = 37;
+  repeated  fixed64 repeated_fixed64  = 38;
+  repeated sfixed32 repeated_sfixed32 = 39;
+  repeated sfixed64 repeated_sfixed64 = 40;
+  repeated    float repeated_float    = 41;
+  repeated   double repeated_double   = 42;
+  repeated     bool repeated_bool     = 43;
+  repeated   string repeated_string   = 44;
+  repeated    bytes repeated_bytes    = 45;
+
+  repeated group RepeatedGroup = 46 {
+    optional int32 a = 47;
+  }
+
+  repeated NestedMessage      repeated_nested_message  = 48;
+
+  repeated NestedEnum      repeated_nested_enum  = 51;
+
+  repeated string repeated_string_piece = 54 [ctype=STRING_PIECE];
+  repeated string repeated_cord = 55 [ctype=CORD];
+
+  // Repeated packed
+  repeated    int32 repeated_packed_int32    = 87 [packed=true];
+  repeated sfixed64 repeated_packed_sfixed64 = 88 [packed=true];
+
+  repeated NestedEnum repeated_packed_nested_enum  = 89 [packed=true];
+
+  // Singular with defaults
+  optional    int32 default_int32    = 61 [default =  41    ];
+  optional    int64 default_int64    = 62 [default =  42    ];
+  optional   uint32 default_uint32   = 63 [default =  43    ];
+  optional   uint64 default_uint64   = 64 [default =  44    ];
+  optional   sint32 default_sint32   = 65 [default = -45    ];
+  optional   sint64 default_sint64   = 66 [default =  46    ];
+  optional  fixed32 default_fixed32  = 67 [default =  47    ];
+  optional  fixed64 default_fixed64  = 68 [default =  48    ];
+  optional sfixed32 default_sfixed32 = 69 [default =  49    ];
+  optional sfixed64 default_sfixed64 = 70 [default = -50    ];
+  optional    float default_float    = 71 [default =  51.5  ];
+  optional   double default_double   = 72 [default =  52e3  ];
+  optional     bool default_bool     = 73 [default = true   ];
+  optional   string default_string   = 74 [default = "hello"];
+  optional    bytes default_bytes    = 75 [default = "world"];
+
+
+  optional  float default_float_inf      = 97  [default =  inf];
+  optional  float default_float_neg_inf  = 98  [default = -inf];
+  optional  float default_float_nan      = 99  [default =  nan];
+  optional double default_double_inf     = 100 [default =  inf];
+  optional double default_double_neg_inf = 101 [default = -inf];
+  optional double default_double_nan     = 102 [default =  nan];
+
+}
+
+message ForeignMessageNano {
+  optional int32 c = 1;
+}
+
+enum ForeignEnumNano {
+  FOREIGN_NANO_FOO = 4;
+  FOREIGN_NANO_BAR = 5;
+  FOREIGN_NANO_BAZ = 6;
+}
+
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_repeated_merge_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_repeated_merge_nano.proto
new file mode 100644
index 00000000..aea48ef7
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_repeated_merge_nano.proto
@@ -0,0 +1,47 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: maxtroy@google.com (Max Cai)
+
+package protobuf_unittest;
+
+import "google/protobuf/nano/unittest_nano.proto";
+
+option java_package = "com.google.protobuf.nano";
+option java_multiple_files = true;
+
+// A container message for testing the merging of repeated fields at a
+// nested level. Other tests will be done using the repeated fields in
+// TestAllTypesNano.
+message TestRepeatedMergeNano {
+
+  optional TestAllTypesNano contained = 1;
+
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_repeated_packables_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_repeated_packables_nano.proto
new file mode 100644
index 00000000..1c78918f
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_repeated_packables_nano.proto
@@ -0,0 +1,95 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: maxtroy@google.com (Max Cai)
+
+package protobuf_unittest;
+
+option java_package = "com.google.protobuf.nano";
+option java_outer_classname = "NanoRepeatedPackables";
+
+enum Enum {
+  OPTION_ONE = 1;
+  OPTION_TWO = 2;
+}
+
+// Two almost identical messages with all packable repeated field types.
+// One with none marked as packed and the other all packed. For
+// compatibility, they should be able to parse each other's serialized
+// forms.
+
+message NonPacked {
+
+  // All packable types, none marked as packed.
+
+  repeated    int32 int32s    = 1;
+  repeated    int64 int64s    = 2;
+  repeated   uint32 uint32s   = 3;
+  repeated   uint64 uint64s   = 4;
+  repeated   sint32 sint32s   = 5;
+  repeated   sint64 sint64s   = 6;
+  repeated  fixed32 fixed32s  = 7;
+  repeated  fixed64 fixed64s  = 8;
+  repeated sfixed32 sfixed32s = 9;
+  repeated sfixed64 sfixed64s = 10;
+  repeated    float floats    = 11;
+  repeated   double doubles   = 12;
+  repeated     bool bools     = 13;
+  repeated     Enum enums     = 14;
+
+  // Noise for testing merged deserialization.
+  optional int32 noise = 15;
+
+}
+
+message Packed {
+
+  // All packable types, all matching the field numbers in NonPacked,
+  // all marked as packed.
+
+  repeated    int32 int32s    = 1  [ packed = true ];
+  repeated    int64 int64s    = 2  [ packed = true ];
+  repeated   uint32 uint32s   = 3  [ packed = true ];
+  repeated   uint64 uint64s   = 4  [ packed = true ];
+  repeated   sint32 sint32s   = 5  [ packed = true ];
+  repeated   sint64 sint64s   = 6  [ packed = true ];
+  repeated  fixed32 fixed32s  = 7  [ packed = true ];
+  repeated  fixed64 fixed64s  = 8  [ packed = true ];
+  repeated sfixed32 sfixed32s = 9  [ packed = true ];
+  repeated sfixed64 sfixed64s = 10 [ packed = true ];
+  repeated    float floats    = 11 [ packed = true ];
+  repeated   double doubles   = 12 [ packed = true ];
+  repeated     bool bools     = 13 [ packed = true ];
+  repeated     Enum enums     = 14 [ packed = true ];
+
+  // Noise for testing merged deserialization.
+  optional int32 noise = 15;
+
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_simple_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_simple_nano.proto
new file mode 100644
index 00000000..0c780c72
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_simple_nano.proto
@@ -0,0 +1,54 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: wink@google.com (Wink Saville)
+//
+
+package protobuf_unittest_import;
+
+option java_package = "com.google.protobuf.nano";
+// Explicit outer classname to suppress legacy info.
+option java_outer_classname = "UnittestSimpleNano";
+
+message SimpleMessageNano {
+  message NestedMessage {
+    optional int32 bb = 1;
+  }
+
+  enum NestedEnum {
+    FOO = 1;
+    BAR = 2;
+    BAZ = 3;
+  }
+
+  optional int32 d = 1 [default = 123];
+  optional NestedMessage nested_msg = 2;
+  optional NestedEnum default_nested_enum = 3 [default = BAZ];
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_single_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_single_nano.proto
new file mode 100644
index 00000000..fcb1539d
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_single_nano.proto
@@ -0,0 +1,38 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: maxtroy@google.com (Max Cai)
+
+package protobuf_unittest_import;
+
+option java_package = "com.google.protobuf.nano";
+
+message SingleMessageNano {
+}
diff --git a/javanano/src/test/java/com/google/protobuf/nano/unittest_stringutf8_nano.proto b/javanano/src/test/java/com/google/protobuf/nano/unittest_stringutf8_nano.proto
new file mode 100644
index 00000000..2bbf2b7b
--- /dev/null
+++ b/javanano/src/test/java/com/google/protobuf/nano/unittest_stringutf8_nano.proto
@@ -0,0 +1,43 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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.
+
+// Author: wink@google.com (Wink Saville)
+//
+
+package protobuf_unittest_import;
+
+option java_package = "com.google.protobuf.nano";
+// Explicit outer classname to suppress legacy info.
+option java_outer_classname = "UnittestStringutf8Nano";
+
+message StringUtf8 {
+  optional string id = 1;
+  repeated string rs = 2;
+}