diff --git a/java/libphonenumber/src/com/google/i18n/phonenumbers/metadata/DefaultMetadataDependenciesProvider.java b/java/libphonenumber/src/com/google/i18n/phonenumbers/metadata/DefaultMetadataDependenciesProvider.java
index 06fd6ad62..ab818acdc 100644
--- a/java/libphonenumber/src/com/google/i18n/phonenumbers/metadata/DefaultMetadataDependenciesProvider.java
+++ b/java/libphonenumber/src/com/google/i18n/phonenumbers/metadata/DefaultMetadataDependenciesProvider.java
@@ -29,7 +29,7 @@ import com.google.i18n.phonenumbers.metadata.source.RegionMetadataSource;
 import com.google.i18n.phonenumbers.metadata.source.RegionMetadataSourceImpl;
 
 /**
- * Provides metadata init & source dependencies when metadata is stored in multi-file mode and
+ * Provides metadata init and source dependencies when metadata is stored in multi-file mode and
  * loaded as a classpath resource.
  */
 public final class DefaultMetadataDependenciesProvider {
diff --git a/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/GeneratePhonePrefixDataEntryPoint.java b/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/GeneratePhonePrefixDataEntryPoint.java
index efabbca35..f4d8a366d 100644
--- a/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/GeneratePhonePrefixDataEntryPoint.java
+++ b/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/GeneratePhonePrefixDataEntryPoint.java
@@ -25,11 +25,13 @@ import java.util.logging.Logger;
 
 /**
  * Entry point class used to invoke the generation of the binary phone prefix data files.
- *
- * @author Philippe Liard
  */
 public class GeneratePhonePrefixDataEntryPoint extends Command {
+
   private static final Logger logger = Logger.getLogger(GeneratePhonePrefixData.class.getName());
+  private static final String USAGE_DESCRIPTION =
+      "usage: GeneratePhonePrefixData /path/to/input/directory /path/to/output/directory"
+          + " [outputJarName]";
 
   @Override
   public String getCommandName() {
@@ -40,16 +42,20 @@ public class GeneratePhonePrefixDataEntryPoint extends Command {
   public boolean start() {
     String[] args = getArgs();
 
-    if (args.length != 3) {
-      logger.log(Level.SEVERE,
-                 "usage: GeneratePhonePrefixData /path/to/input/directory "
-                 + "/path/to/output/directory");
+    if (args.length < 2 || args.length > 3) {
+      logger.log(Level.SEVERE, USAGE_DESCRIPTION);
       return false;
     }
     try {
-      GeneratePhonePrefixData generatePhonePrefixData =
-          new GeneratePhonePrefixData(new File(args[1]), new PhonePrefixDataIOHandler(new File(args[2])));
-      generatePhonePrefixData.run();
+      File inputPath = new File(args[0]);
+      File outputPath = new File(args[1]);
+      AbstractPhonePrefixDataIOHandler ioHandler =
+          args.length == 2
+              ? new PhonePrefixDataIOHandler(outputPath)
+              : new JarPhonePrefixDataIOHandler(
+                  outputPath, args[2], GeneratePhonePrefixData.class.getPackage());
+      GeneratePhonePrefixData dataGenerator = new GeneratePhonePrefixData(inputPath, ioHandler);
+      dataGenerator.run();
     } catch (IOException e) {
       logger.log(Level.SEVERE, e.getMessage());
       return false;
diff --git a/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/GenerateTimeZonesMapDataEntryPoint.java b/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/GenerateTimeZonesMapDataEntryPoint.java
index 77a7e5ea6..edc7a5d18 100644
--- a/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/GenerateTimeZonesMapDataEntryPoint.java
+++ b/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/GenerateTimeZonesMapDataEntryPoint.java
@@ -31,6 +31,9 @@ import java.util.logging.Logger;
  */
 public class GenerateTimeZonesMapDataEntryPoint extends Command {
   private static final Logger logger = Logger.getLogger(GenerateTimeZonesMapData.class.getName());
+  private static final String USAGE_DESCRIPTION =
+      "usage: GenerateTimeZonesMapData /path/to/input/directory /path/to/output/directory"
+          + " [outputJarName]";
 
   @Override
   public String getCommandName() {
@@ -41,15 +44,19 @@ public class GenerateTimeZonesMapDataEntryPoint extends Command {
   public boolean start() {
     String[] args = getArgs();
 
-    if (args.length != 3) {
-      logger.log(Level.SEVERE,
-                 "usage: GenerateTimeZonesMapData /path/to/input/text_file "
-                 + "/path/to/output/directory");
+    if (args.length < 2 || args.length > 3) {
+      logger.log(Level.SEVERE, USAGE_DESCRIPTION);
       return false;
     }
     try {
-      GenerateTimeZonesMapData generateTimeZonesMapData = new GenerateTimeZonesMapData(
-          new File(args[1]), new PhonePrefixDataIOHandler(new File(args[2])));
+      File inputPath = new File(args[0]);
+      File outputPath = new File(args[1]);
+      AbstractPhonePrefixDataIOHandler ioHandler =
+          args.length == 2
+              ? new PhonePrefixDataIOHandler(outputPath)
+              : new JarPhonePrefixDataIOHandler(
+                  outputPath, args[2], GeneratePhonePrefixData.class.getPackage());
+      GenerateTimeZonesMapData generateTimeZonesMapData = new GenerateTimeZonesMapData(inputPath, ioHandler);
       generateTimeZonesMapData.run();
     } catch (IOException e) {
       logger.log(Level.SEVERE, e.getMessage());
diff --git a/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/JarPhonePrefixDataIOHandler.java b/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/JarPhonePrefixDataIOHandler.java
new file mode 100644
index 000000000..8a87a43c3
--- /dev/null
+++ b/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/JarPhonePrefixDataIOHandler.java
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2012 The Libphonenumber Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.i18n.phonenumbers.buildtools;
+
+import java.io.BufferedInputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.jar.Attributes;
+import java.util.jar.JarEntry;
+import java.util.jar.JarOutputStream;
+import java.util.jar.Manifest;
+
+/**
+ * Implementation of the AbstractPhonePrefixDataIOHandler required by the GeneratePhonePrefixData
+ * class used here to create the output files and add them to the resulting JAR.
+ */
+public class JarPhonePrefixDataIOHandler extends AbstractPhonePrefixDataIOHandler {
+
+  // Base name of the output JAR files. It also forms part of the name of the package
+  // containing the generated binary data.
+  private final String jarBase;
+  // The path to the output directory.
+  private final File outputPath;
+  // The JAR output stream used by the JarPhonePrefixDataIOHandler.
+  private final JarOutputStream jarOutputStream;
+  // The package that will be used to create the JAR entry file.
+  private final Package outputPackage;
+
+  public JarPhonePrefixDataIOHandler(File outputPath, String outputName, Package outputPackage)
+      throws IOException {
+    if (outputPath.exists()) {
+      if (!outputPath.isDirectory()) {
+        throw new IOException("Expected directory: " + outputPath.getAbsolutePath());
+      }
+    } else {
+      if (!outputPath.mkdirs()) {
+        throw new IOException("Could not create directory " + outputPath.getAbsolutePath());
+      }
+    }
+    this.outputPath = outputPath;
+    this.jarBase = outputName;
+    this.outputPackage = outputPackage;
+    jarOutputStream = createJar();
+  }
+
+  private JarOutputStream createJar() throws IOException {
+    Manifest manifest = new java.util.jar.Manifest();
+    manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
+    return new JarOutputStream(new FileOutputStream(new File(outputPath, jarBase + ".jar")));
+  }
+
+  /**
+   * Adds the provided file to the created JAR.
+   */
+  @Override
+  public void addFileToOutput(File file) throws IOException {
+    JarEntry entry =
+        new JarEntry(
+            outputPackage.getName().replace('.', '/')
+                + String.format("/%s/", jarBase)
+                + file.getPath());
+    entry.setTime(file.lastModified());
+    jarOutputStream.putNextEntry(entry);
+    BufferedInputStream bufferedInputStream = null;
+
+    try {
+      bufferedInputStream = new BufferedInputStream(new FileInputStream(file));
+      byte[] buffer = new byte[4096];
+
+      for (int read; (read = bufferedInputStream.read(buffer)) > 0; ) {
+        jarOutputStream.write(buffer, 0, read);
+      }
+      if (!file.delete()) {
+        throw new IOException("Could not delete: " + file.getAbsolutePath());
+      }
+    } finally {
+      jarOutputStream.closeEntry();
+      closeFile(bufferedInputStream);
+    }
+  }
+
+  @Override
+  public File createFile(String path) {
+    return new File(path);
+  }
+
+  @Override
+  public void close() {
+    closeFile(jarOutputStream);
+  }
+}
diff --git a/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/PhonePrefixDataIOHandler.java b/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/PhonePrefixDataIOHandler.java
index 72d3a626b..0584a1519 100644
--- a/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/PhonePrefixDataIOHandler.java
+++ b/tools/java/java-build/src/com/google/i18n/phonenumbers/buildtools/PhonePrefixDataIOHandler.java
@@ -20,10 +20,11 @@ import java.io.File;
 import java.io.IOException;
 
 /**
- * Implementation of the IOHandler required by the GeneratePhonePrefixData class used here to create
- * the output files.
+ * Implementation of the AbstractPhonePrefixDataIOHandler required by the GeneratePhonePrefixData
+ * class used here to create the output files.
  */
 class PhonePrefixDataIOHandler extends AbstractPhonePrefixDataIOHandler {
+
   // The path to the output directory.
   private final File outputPath;
 
@@ -40,11 +41,14 @@ class PhonePrefixDataIOHandler extends AbstractPhonePrefixDataIOHandler {
     this.outputPath = outputPath;
   }
 
+  /**
+   * This is a <b>no-op</b>.
+   *
+   * <p>This would be the place dealing with the addition of the provided file to the resulting JAR
+   * if the global output was a JAR instead of a directory containing the binary files.
+   */
   @Override
-  public void addFileToOutput(File file) throws IOException {
-    // Do nothing. This would be the place dealing with the addition of the provided file to the
-    // resulting JAR if the global output was a JAR instead of a directory containing the binary
-    // files.
+  public void addFileToOutput(File file) {
   }
 
   @Override
@@ -52,8 +56,10 @@ class PhonePrefixDataIOHandler extends AbstractPhonePrefixDataIOHandler {
     return new File(outputPath, path);
   }
 
+  /**
+   * This is a <b>no-op</b>, as no resource needs to be released.
+   */
   @Override
   public void close() {
-    // Do nothing as no resource needs to be released.
   }
 }
diff --git a/tools/java/java-build/test/com/google/i18n/phonenumbers/buildtools/JarPhonePrefixDataIOHandlerTest.java b/tools/java/java-build/test/com/google/i18n/phonenumbers/buildtools/JarPhonePrefixDataIOHandlerTest.java
new file mode 100644
index 000000000..bcb8cae1e
--- /dev/null
+++ b/tools/java/java-build/test/com/google/i18n/phonenumbers/buildtools/JarPhonePrefixDataIOHandlerTest.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2012 The Libphonenumber Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.i18n.phonenumbers.buildtools;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Enumeration;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import junit.framework.TestCase;
+
+/**
+ * Unittests for JarPhonePrefixDataIOHandler.java
+ */
+public class JarPhonePrefixDataIOHandlerTest extends TestCase {
+
+  private static final String TESTING_JAR_BASE = "testing_data";
+  private static final Logger logger =
+      Logger.getLogger(JarPhonePrefixDataIOHandlerTest.class.getName());
+
+  public void testAddFileToOutput() {
+    File outputFile = null;
+
+    try {
+      // Create the output jar.
+      File outputPath = new File("/tmp/build");
+      Package outputPackage = JarPhonePrefixDataIOHandlerTest.class.getPackage();
+
+      JarPhonePrefixDataIOHandler ioHandler =
+          new JarPhonePrefixDataIOHandler(outputPath, TESTING_JAR_BASE, outputPackage);
+      outputFile = File.createTempFile("outputTestFile", "txt");
+      ioHandler.addFileToOutput(outputFile);
+      ioHandler.close();
+
+      JarFile outputJar = new JarFile(new File(outputPath, TESTING_JAR_BASE + ".jar"));
+      // Test if there is exactly one entry in the jar.
+      Enumeration<JarEntry> entries = outputJar.entries();
+      int entriesCount = 0;
+      while (entries.hasMoreElements()) {
+        entriesCount++;
+        entries.nextElement();
+      }
+      assertEquals(1, entriesCount);
+
+      // Test if the entry file in the jar has the expected path.
+      String jarEntryPath =
+          "com/google/i18n/phonenumbers/buildtools/"
+              + TESTING_JAR_BASE
+              + "/"
+              + outputFile.getPath();
+      JarEntry jarEntry = outputJar.getJarEntry(jarEntryPath);
+      assertNotNull("Output file not found inside the jar.", jarEntry);
+    } catch (IOException e) {
+      logger.log(Level.SEVERE, e.getMessage());
+      fail();
+    } finally {
+      if (outputFile != null && outputFile.exists()) {
+        outputFile.delete();
+      }
+    }
+  }
+}
\ No newline at end of file