Implement hashCode() and equals() behind a generator option.

The option is only called 'generate_equals' because:
- equals() is the main thing; hashCode() is there only to
  complement equals();
- it's shorter;
- toString() should not be included in this option because
  it's more for debugging and it's more likely to stop
  ProGuard from working well.

Also shortened the "has bit" expression; was
((bitField & mask) == mask), now ((bitField & mask) != 0).
Both the Java code and the bytecode are slightly shorter.

Change-Id: Ic309a08a60883bf454eb6612679aa99611620e76

17 files changed, 915 insertions, 65 deletions

diff --git a/java/pom.xml b/java/pom.xml
index dcc1cfa..cfa35a5 100644
--- a/java/pom.xml
+++ b/java/pom.xml
@@ -133,7 +133,7 @@
                 </exec>
 		<!-- java nano -->
                 <exec executable="../src/protoc">
-                  <arg value="--javanano_out=java_package=google/protobuf/unittest_import_nano.proto|com.google.protobuf.nano,java_outer_classname=google/protobuf/unittest_import_nano.proto|UnittestImportNano:target/generated-test-sources" />
+                  <arg value="--javanano_out=java_package=google/protobuf/unittest_import_nano.proto|com.google.protobuf.nano,java_outer_classname=google/protobuf/unittest_import_nano.proto|UnittestImportNano,generate_equals=true:target/generated-test-sources" />
                   <arg value="--proto_path=../src" />
                   <arg value="--proto_path=src/test/java" />
                   <arg value="../src/google/protobuf/unittest_nano.proto" />
@@ -154,13 +154,13 @@
                   <arg value="../src/google/protobuf/unittest_extension_nano.proto" />
                 </exec>
                 <exec executable="../src/protoc">
-                  <arg value="--javanano_out=java_nano_generate_has=true:target/generated-test-sources" />
+                  <arg value="--javanano_out=java_nano_generate_has=true,generate_equals=true:target/generated-test-sources" />
                   <arg value="--proto_path=../src" />
                   <arg value="--proto_path=src/test/java" />
                   <arg value="../src/google/protobuf/unittest_has_nano.proto" />
                 </exec>
                 <exec executable="../src/protoc">
-                  <arg value="--javanano_out=optional_field_style=accessors:target/generated-test-sources" />
+                  <arg value="--javanano_out=optional_field_style=accessors,generate_equals=true:target/generated-test-sources" />
                   <arg value="--proto_path=../src" />
                   <arg value="--proto_path=src/test/java" />
                   <arg value="../src/google/protobuf/unittest_accessors_nano.proto" />
@@ -173,7 +173,7 @@
                   <arg value="../src/google/protobuf/unittest_enum_class_multiple_nano.proto" />
                 </exec>
                 <exec executable="../src/protoc">
-                  <arg value="--javanano_out=optional_field_style=reftypes:target/generated-test-sources" />
+                  <arg value="--javanano_out=optional_field_style=reftypes,generate_equals=true:target/generated-test-sources" />
                   <arg value="--proto_path=../src" />
                   <arg value="--proto_path=src/test/java" />
                   <arg value="../src/google/protobuf/unittest_reference_types_nano.proto" />
diff --git a/java/src/main/java/com/google/protobuf/nano/InternalNano.java b/java/src/main/java/com/google/protobuf/nano/InternalNano.java
index 4930951..ce4a206 100644
--- a/java/src/main/java/com/google/protobuf/nano/InternalNano.java
+++ b/java/src/main/java/com/google/protobuf/nano/InternalNano.java
@@ -31,6 +31,7 @@
 package com.google.protobuf.nano;
 
 import java.io.UnsupportedEncodingException;
+import java.util.Arrays;
 
 /**
  * The classes contained within are used internally by the Protocol Buffer
@@ -40,7 +41,10 @@ import java.io.UnsupportedEncodingException;
  *
  * @author kenton@google.com (Kenton Varda)
  */
-public class InternalNano {
+public final class InternalNano {
+
+  private InternalNano() {}
+
   /**
    * Helper called by generated code to construct default values for string
    * fields.
@@ -69,7 +73,7 @@ public class InternalNano {
    * converts from the generated string to the string we actually want.  The
    * generated code calls this automatically.
    */
-  public static final String stringDefaultValue(String bytes) {
+  public static String stringDefaultValue(String bytes) {
     try {
       return new String(bytes.getBytes("ISO-8859-1"), "UTF-8");
     } catch (UnsupportedEncodingException e) {
@@ -88,7 +92,7 @@ public class InternalNano {
    * 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 final byte[] bytesDefaultValue(String bytes) {
+  public static byte[] bytesDefaultValue(String bytes) {
     try {
       return bytes.getBytes("ISO-8859-1");
     } catch (UnsupportedEncodingException e) {
@@ -103,11 +107,215 @@ public class InternalNano {
    * Helper function to convert a string into UTF-8 while turning the
    * UnsupportedEncodingException to a RuntimeException.
    */
-  public static final byte[] copyFromUtf8(final String text) {
+  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/java/src/main/java/com/google/protobuf/nano/UnknownFieldData.java b/java/src/main/java/com/google/protobuf/nano/UnknownFieldData.java
index 0db2a83..833ed2a 100644
--- a/java/src/main/java/com/google/protobuf/nano/UnknownFieldData.java
+++ b/java/src/main/java/com/google/protobuf/nano/UnknownFieldData.java
@@ -30,6 +30,8 @@
 
 package com.google.protobuf.nano;
 
+import java.util.Arrays;
+
 /**
  * Stores unknown fields. These might be extensions or fields that the generated API doesn't
  * know about yet.
@@ -37,6 +39,7 @@ package com.google.protobuf.nano;
  * @author bduff@google.com (Brian Duff)
  */
 public final class UnknownFieldData {
+
   final int tag;
   final byte[] bytes;
 
@@ -44,4 +47,25 @@ public final class UnknownFieldData {
     this.tag = tag;
     this.bytes = 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/java/src/test/java/com/google/protobuf/NanoTest.java b/java/src/test/java/com/google/protobuf/NanoTest.java
index 1149c40..b9061e9 100644
--- a/java/src/test/java/com/google/protobuf/NanoTest.java
+++ b/java/src/test/java/com/google/protobuf/NanoTest.java
@@ -60,6 +60,7 @@ import junit.framework.TestCase;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
 
 /**
@@ -2684,6 +2685,224 @@ public class NanoTest extends TestCase {
     assertHasWireData(message, false);
   }
 
+  public void testHashCodeEquals() throws Exception {
+    // Complete equality:
+    TestAllTypesNano a = createMessageForHashCodeEqualsTest();
+    TestAllTypesNano aEquivalent = createMessageForHashCodeEqualsTest();
+
+    // 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();
+    System.out.println("equals: " + f.equals(fEquivalent));
+    System.out.println("hashCode: " + f.hashCode() + " vs " + fEquivalent.hashCode());
+
+    // 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
+    };
+    // We set the _nan fields to something other than nan, because equality
+    // is defined for nan such that Float.NaN != Float.NaN, which makes any
+    // instance of TestAllTypesNano unequal to any other instance unless
+    // these fields are set. This is also the behavior of the regular java
+    // generator when the value of a field is NaN.
+    message.defaultFloatNan = 1.0f;
+    message.defaultDoubleNan = 1.0;
+    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
+    };
+    message.defaultFloatNan = 1.0f;
+    return message;
+  }
+
+  private TestNanoAccessors createMessageWithAccessorsForHashCodeEqualsTest() {
+    TestNanoAccessors message = new TestNanoAccessors()
+        .setOptionalInt32(5)
+        .setOptionalString("Hello")
+        .setOptionalBytes(new byte[] {1, 2, 3})
+        .setOptionalNestedMessage(new TestNanoAccessors.NestedMessage().setBb(27))
+        .setOptionalNestedEnum(TestNanoAccessors.BAR)
+        .setDefaultFloatNan(1.0f);
+    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.getOptionalNestedMessage(),
+      message.getOptionalNestedMessage()
+    };
+    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 testNullRepeatedFields() throws Exception {
     // Check that serialization after explicitly setting a repeated field
     // to null doesn't NPE.
diff --git a/src/google/protobuf/compiler/javanano/javanano_enum_field.cc b/src/google/protobuf/compiler/javanano/javanano_enum_field.cc
index 3c4b978..b9f4fd0 100644
--- a/src/google/protobuf/compiler/javanano/javanano_enum_field.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_enum_field.cc
@@ -159,8 +159,46 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
   }
 }
 
-string EnumFieldGenerator::GetBoxedType() const {
-  return ClassName(params_, descriptor_->enum_type());
+void EnumFieldGenerator::GenerateEqualsCode(io::Printer* printer) const {
+  if (params_.use_reference_types_for_primitives()) {
+    printer->Print(variables_,
+      "if (this.$name$ == null) {\n"
+      "  if (other.$name$ != null) {\n"
+      "    return false;\n"
+      "  }\n"
+      "} else if (!this.$name$.equals(other.$name$)) {\n"
+      "  return false;"
+      "}\n");
+  } else {
+    // We define equality as serialized form equality. If generate_has(),
+    // then if the field value equals the default value in both messages,
+    // but one's 'has' field is set and the other's is not, the serialized
+    // forms are different and we should return false.
+    printer->Print(variables_,
+      "if (this.$name$ != other.$name$");
+    if (params_.generate_has()) {
+      printer->Print(variables_,
+        "\n"
+        "    || (this.$name$ == $default$\n"
+        "        && this.has$capitalized_name$ != other.has$capitalized_name$)");
+    }
+    printer->Print(") {\n"
+      "  return false;\n"
+      "}\n");
+  }
+}
+
+void EnumFieldGenerator::GenerateHashCodeCode(io::Printer* printer) const {
+  printer->Print(
+    "result = 31 * result + ");
+  if (params_.use_reference_types_for_primitives()) {
+    printer->Print(variables_,
+      "(this.$name$ == null ? 0 : this.$name$)");
+  } else {
+    printer->Print(variables_,
+      "this.$name$");
+  }
+  printer->Print(";\n");
 }
 
 // ===================================================================
@@ -227,8 +265,19 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
     "}\n");
 }
 
-string AccessorEnumFieldGenerator::GetBoxedType() const {
-  return ClassName(params_, descriptor_->enum_type());
+void AccessorEnumFieldGenerator::
+GenerateEqualsCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "if ($different_has$\n"
+    "    || $name$_ != other.$name$_) {\n"
+    "  return false;\n"
+    "}\n");
+}
+
+void AccessorEnumFieldGenerator::
+GenerateHashCodeCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "result = 31 * result + $name$_;\n");
 }
 
 // ===================================================================
@@ -366,8 +415,20 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
   }
 }
 
-string RepeatedEnumFieldGenerator::GetBoxedType() const {
-  return ClassName(params_, descriptor_->enum_type());
+void RepeatedEnumFieldGenerator::
+GenerateEqualsCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "if (!com.google.protobuf.nano.InternalNano.equals(\n"
+    "    this.$name$, other.$name$)) {\n"
+    "  return false;\n"
+    "}\n");
+}
+
+void RepeatedEnumFieldGenerator::
+GenerateHashCodeCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "result = 31 * result\n"
+    "    + com.google.protobuf.nano.InternalNano.hashCode(this.$name$);\n");
 }
 
 }  // namespace javanano
diff --git a/src/google/protobuf/compiler/javanano/javanano_enum_field.h b/src/google/protobuf/compiler/javanano/javanano_enum_field.h
index 934aaaa..af317d8 100644
--- a/src/google/protobuf/compiler/javanano/javanano_enum_field.h
+++ b/src/google/protobuf/compiler/javanano/javanano_enum_field.h
@@ -55,8 +55,8 @@ class EnumFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
-
-  string GetBoxedType() const;
+  void GenerateEqualsCode(io::Printer* printer) const;
+  void GenerateHashCodeCode(io::Printer* printer) const;
 
  private:
   const FieldDescriptor* descriptor_;
@@ -77,8 +77,8 @@ class AccessorEnumFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
-
-  string GetBoxedType() const;
+  void GenerateEqualsCode(io::Printer* printer) const;
+  void GenerateHashCodeCode(io::Printer* printer) const;
 
  private:
   const FieldDescriptor* descriptor_;
@@ -98,8 +98,8 @@ class RepeatedEnumFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
-
-  string GetBoxedType() const;
+  void GenerateEqualsCode(io::Printer* printer) const;
+  void GenerateHashCodeCode(io::Printer* printer) const;
 
  private:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/javanano/javanano_field.h b/src/google/protobuf/compiler/javanano/javanano_field.h
index dad2e7a..150ec19 100644
--- a/src/google/protobuf/compiler/javanano/javanano_field.h
+++ b/src/google/protobuf/compiler/javanano/javanano_field.h
@@ -62,8 +62,8 @@ class FieldGenerator {
   virtual void GenerateMergingCode(io::Printer* printer) const = 0;
   virtual void GenerateSerializationCode(io::Printer* printer) const = 0;
   virtual void GenerateSerializedSizeCode(io::Printer* printer) const = 0;
-
-  virtual string GetBoxedType() const = 0;
+  virtual void GenerateEqualsCode(io::Printer* printer) const = 0;
+  virtual void GenerateHashCodeCode(io::Printer* printer) const = 0;
 
  protected:
   const Params& params_;
diff --git a/src/google/protobuf/compiler/javanano/javanano_generator.cc b/src/google/protobuf/compiler/javanano/javanano_generator.cc
index 48c3a21..5c8bcb6 100644
--- a/src/google/protobuf/compiler/javanano/javanano_generator.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_generator.cc
@@ -125,6 +125,8 @@ bool JavaNanoGenerator::Generate(const FileDescriptor* file,
     } else if (options[i].first == "optional_field_style") {
       params.set_optional_field_accessors(options[i].second == "accessors");
       params.set_use_reference_types_for_primitives(options[i].second == "reftypes");
+    } else if (options[i].first == "generate_equals") {
+      params.set_generate_equals(options[i].second == "true");
     } else {
       *error = "Ignore unknown javanano generator option: " + options[i].first;
     }
diff --git a/src/google/protobuf/compiler/javanano/javanano_helpers.cc b/src/google/protobuf/compiler/javanano/javanano_helpers.cc
index ed6dbd7..95ee670 100644
--- a/src/google/protobuf/compiler/javanano/javanano_helpers.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_helpers.cc
@@ -482,7 +482,7 @@ string GenerateGetBit(int bit_index) {
   int bit_in_var_index = bit_index % 32;
 
   string mask = kBitMasks[bit_in_var_index];
-  string result = "((" + var_name + " & " + mask + ") == " + mask + ")";
+  string result = "((" + var_name + " & " + mask + ") != 0)";
   return result;
 }
 
@@ -504,11 +504,22 @@ string GenerateClearBit(int bit_index) {
   return result;
 }
 
+string GenerateDifferentBit(int bit_index) {
+  string var_name = GetBitFieldNameForBit(bit_index);
+  int bit_in_var_index = bit_index % 32;
+
+  string mask = kBitMasks[bit_in_var_index];
+  string result = "((" + var_name + " & " + mask
+      + ") != (other." + var_name + " & " + mask + "))";
+  return result;
+}
+
 void SetBitOperationVariables(const string name,
     int bitIndex, map<string, string>* variables) {
   (*variables)["get_" + name] = GenerateGetBit(bitIndex);
   (*variables)["set_" + name] = GenerateSetBit(bitIndex);
   (*variables)["clear_" + name] = GenerateClearBit(bitIndex);
+  (*variables)["different_" + name] = GenerateDifferentBit(bitIndex);
 }
 
 }  // namespace javanano
diff --git a/src/google/protobuf/compiler/javanano/javanano_helpers.h b/src/google/protobuf/compiler/javanano/javanano_helpers.h
index cddc077..753a4bd 100644
--- a/src/google/protobuf/compiler/javanano/javanano_helpers.h
+++ b/src/google/protobuf/compiler/javanano/javanano_helpers.h
@@ -141,30 +141,37 @@ string DefaultValue(const Params& params, const FieldDescriptor* field);
 
 // Methods for shared bitfields.
 
-// Gets the name of the shared bitfield for the given index.
+// Gets the name of the shared bitfield for the given field index.
 string GetBitFieldName(int index);
 
 // Gets the name of the shared bitfield for the given bit index.
 // Effectively, GetBitFieldName(bit_index / 32)
 string GetBitFieldNameForBit(int bit_index);
 
-// Generates the java code for the expression that returns the boolean value
-// of the bit of the shared bitfields for the given bit index.
-// Example: "((bitField1_ & 0x04) == 0x04)"
+// Generates the java code for the expression that returns whether the bit at
+// the given bit index is set.
+// Example: "((bitField1_ & 0x04000000) != 0)"
 string GenerateGetBit(int bit_index);
 
-// Generates the java code for the expression that sets the bit of the shared
-// bitfields for the given bit index.
-// Example: "bitField1_ = (bitField1_ | 0x04)"
+// Generates the java code for the expression that sets the bit at the given
+// bit index.
+// Example: "bitField1_ |= 0x04000000"
 string GenerateSetBit(int bit_index);
 
-// Generates the java code for the expression that clears the bit of the shared
-// bitfields for the given bit index.
-// Example: "bitField1_ = (bitField1_ & ~0x04)"
+// Generates the java code for the expression that clears the bit at the given
+// bit index.
+// Example: "bitField1_ = (bitField1_ & ~0x04000000)"
 string GenerateClearBit(int bit_index);
 
-// Sets the 'get_*', 'set_*' and 'clear_*' variables, where * is the given bit
-// field name, to the appropriate Java expressions for the given bit index.
+// Generates the java code for the expression that returns whether the bit at
+// the given bit index contains different values in the current object and
+// another object accessible via the variable 'other'.
+// Example: "((bitField1_ & 0x04000000) != (other.bitField1_ & 0x04000000))"
+string GenerateDifferentBit(int bit_index);
+
+// Sets the 'get_*', 'set_*', 'clear_*' and 'different_*' variables, where * is
+// the given name of the bit, to the appropriate Java expressions for the given
+// bit index.
 void SetBitOperationVariables(const string name,
     int bitIndex, map<string, string>* variables);
 
diff --git a/src/google/protobuf/compiler/javanano/javanano_message.cc b/src/google/protobuf/compiler/javanano/javanano_message.cc
index c55ca55..63f8955 100644
--- a/src/google/protobuf/compiler/javanano/javanano_message.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_message.cc
@@ -198,6 +198,11 @@ void MessageGenerator::Generate(io::Printer* printer) {
 
   GenerateClear(printer);
 
+  if (params_.generate_equals()) {
+    GenerateEquals(printer);
+    GenerateHashCode(printer);
+  }
+
   // If we have an extension range, generate accessors for extensions.
   if (params_.store_unknown_fields()
       && descriptor_->extension_range_count() > 0) {
@@ -326,11 +331,11 @@ void MessageGenerator::GenerateMergeFromMethods(io::Printer* printer) {
   if (params_.store_unknown_fields()) {
     printer->Print(
         "if (unknownFieldData == null) {\n"
-        "  unknownFieldData = \n"
+        "  unknownFieldData =\n"
         "      new java.util.ArrayList<com.google.protobuf.nano.UnknownFieldData>();\n"
         "}\n"
-        "if (!com.google.protobuf.nano.WireFormatNano.storeUnknownField(unknownFieldData, \n"
-        "    input, tag)) {\n"
+        "if (!com.google.protobuf.nano.WireFormatNano.storeUnknownField(\n"
+        "    unknownFieldData, input, tag)) {\n"
         "  return this;\n"
         "}\n");
   } else {
@@ -427,6 +432,79 @@ void MessageGenerator::GenerateClear(io::Printer* printer) {
     "}\n");
 }
 
+void MessageGenerator::GenerateEquals(io::Printer* printer) {
+  // Don't override if there are no fields. We could generate an
+  // equals method that compares types, but often empty messages
+  // are used as namespaces.
+  if (descriptor_->field_count() == 0 && !params_.store_unknown_fields()) {
+    return;
+  }
+
+  printer->Print(
+    "\n"
+    "@Override\n"
+    "public boolean equals(Object o) {\n");
+  printer->Indent();
+  printer->Print(
+    "if (o == this) {\n"
+    "  return true;\n"
+    "}\n"
+    "if (!(o instanceof $classname$)) {\n"
+    "  return false;\n"
+    "}\n"
+    "$classname$ other = ($classname$) o;\n",
+    "classname", descriptor_->name());
+
+  for (int i = 0; i < descriptor_->field_count(); i++) {
+    const FieldDescriptor* field = descriptor_->field(i);
+    field_generators_.get(field).GenerateEqualsCode(printer);
+  }
+
+  if (params_.store_unknown_fields()) {
+    printer->Print(
+      "if (unknownFieldData == null || unknownFieldData.isEmpty()) {\n"
+      "  return other.unknownFieldData == null || other.unknownFieldData.isEmpty();"
+      "} else {\n"
+      "  return unknownFieldData.equals(other.unknownFieldData);\n"
+      "}\n");
+  } else {
+    printer->Print(
+      "return true;\n");
+  }
+
+  printer->Outdent();
+  printer->Print("}\n");
+}
+
+void MessageGenerator::GenerateHashCode(io::Printer* printer) {
+  if (descriptor_->field_count() == 0 && !params_.store_unknown_fields()) {
+    return;
+  }
+
+  printer->Print(
+    "\n"
+    "@Override\n"
+    "public int hashCode() {\n");
+  printer->Indent();
+
+  printer->Print("int result = 17;\n");
+  for (int i = 0; i < descriptor_->field_count(); i++) {
+    const FieldDescriptor* field = descriptor_->field(i);
+    field_generators_.get(field).GenerateHashCodeCode(printer);
+  }
+
+  if (params_.store_unknown_fields()) {
+    printer->Print(
+      "result = 31 * result + (unknownFieldData == null || unknownFieldData.isEmpty()\n"
+      "    ? 0 : unknownFieldData.hashCode());\n");
+  }
+
+  printer->Print("return result;\n");
+
+  printer->Outdent();
+  printer->Print("}\n");
+}
+
 // ===================================================================
 
 }  // namespace javanano
diff --git a/src/google/protobuf/compiler/javanano/javanano_message.h b/src/google/protobuf/compiler/javanano/javanano_message.h
index d59ec9f..f87f84f 100644
--- a/src/google/protobuf/compiler/javanano/javanano_message.h
+++ b/src/google/protobuf/compiler/javanano/javanano_message.h
@@ -36,9 +36,10 @@
 #define GOOGLE_PROTOBUF_COMPILER_JAVA_MESSAGE_H__
 
 #include <string>
-#include <google/protobuf/stubs/common.h>
-#include <google/protobuf/compiler/javanano/javanano_params.h>
+#include <google/protobuf/compiler/javanano/javanano_helpers.h>
 #include <google/protobuf/compiler/javanano/javanano_field.h>
+#include <google/protobuf/compiler/javanano/javanano_params.h>
+#include <google/protobuf/stubs/common.h>
 
 namespace google {
 namespace protobuf {
@@ -76,6 +77,8 @@ class MessageGenerator {
                                  const FieldDescriptor* field);
 
   void GenerateClear(io::Printer* printer);
+  void GenerateEquals(io::Printer* printer);
+  void GenerateHashCode(io::Printer* printer);
 
   const Params& params_;
   const Descriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/javanano/javanano_message_field.cc b/src/google/protobuf/compiler/javanano/javanano_message_field.cc
index 02253f9..9f8298c 100644
--- a/src/google/protobuf/compiler/javanano/javanano_message_field.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_message_field.cc
@@ -126,8 +126,25 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
     "}\n");
 }
 
-string MessageFieldGenerator::GetBoxedType() const {
-  return ClassName(params_, descriptor_->message_type());
+void MessageFieldGenerator::
+GenerateEqualsCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "if (this.$name$ == null) { \n"
+    "  if (other.$name$ != null) {\n"
+    "    return false;\n"
+    "  }\n"
+    "} else {\n"
+    "  if (!this.$name$.equals(other.$name$)) {\n"
+    "    return false;\n"
+    "  }\n"
+    "}\n");
+}
+
+void MessageFieldGenerator::
+GenerateHashCodeCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "result = 31 * result +\n"
+    "    (this.$name$ == null ? 0 : this.$name$.hashCode());\n");
 }
 
 // ===================================================================
@@ -203,8 +220,22 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
     "}\n");
 }
 
-string AccessorMessageFieldGenerator::GetBoxedType() const {
-  return ClassName(params_, descriptor_->message_type());
+void AccessorMessageFieldGenerator::
+GenerateEqualsCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "if ($name$_ == null) {\n"
+    "  if (other.$name$_ != null) {\n"
+    "    return false;\n"
+    "  }\n"
+    "} else if (!$name$_.equals(other.$name$_)) {\n"
+    "  return false;\n"
+    "}\n");
+}
+
+void AccessorMessageFieldGenerator::
+GenerateHashCodeCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "result = 31 * result + ($name$_ == null ? 0 : $name$_.hashCode());\n");
 }
 
 // ===================================================================
@@ -291,8 +322,20 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
     "}\n");
 }
 
-string RepeatedMessageFieldGenerator::GetBoxedType() const {
-  return ClassName(params_, descriptor_->message_type());
+void RepeatedMessageFieldGenerator::
+GenerateEqualsCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "if (!com.google.protobuf.nano.InternalNano.equals(\n"
+    "    this.$name$, other.$name$)) {\n"
+    "  return false;\n"
+    "}\n");
+}
+
+void RepeatedMessageFieldGenerator::
+GenerateHashCodeCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "result = 31 * result\n"
+    "    + com.google.protobuf.nano.InternalNano.hashCode(this.$name$);\n");
 }
 
 }  // namespace javanano
diff --git a/src/google/protobuf/compiler/javanano/javanano_message_field.h b/src/google/protobuf/compiler/javanano/javanano_message_field.h
index 9807513..b724351 100644
--- a/src/google/protobuf/compiler/javanano/javanano_message_field.h
+++ b/src/google/protobuf/compiler/javanano/javanano_message_field.h
@@ -55,8 +55,8 @@ class MessageFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
-
-  string GetBoxedType() const;
+  void GenerateEqualsCode(io::Printer* printer) const;
+  void GenerateHashCodeCode(io::Printer* printer) const;
 
  private:
   const FieldDescriptor* descriptor_;
@@ -77,8 +77,8 @@ class AccessorMessageFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
-
-  string GetBoxedType() const;
+  void GenerateEqualsCode(io::Printer* printer) const;
+  void GenerateHashCodeCode(io::Printer* printer) const;
 
  private:
   const FieldDescriptor* descriptor_;
@@ -99,8 +99,8 @@ class RepeatedMessageFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
-
-  string GetBoxedType() const;
+  void GenerateEqualsCode(io::Printer* printer) const;
+  void GenerateHashCodeCode(io::Printer* printer) const;
 
  private:
   const FieldDescriptor* descriptor_;
diff --git a/src/google/protobuf/compiler/javanano/javanano_params.h b/src/google/protobuf/compiler/javanano/javanano_params.h
index 6e5379c..24aece3 100644
--- a/src/google/protobuf/compiler/javanano/javanano_params.h
+++ b/src/google/protobuf/compiler/javanano/javanano_params.h
@@ -61,6 +61,7 @@ class Params {
   bool java_enum_style_;
   bool optional_field_accessors_;
   bool use_reference_types_for_primitives_;
+  bool generate_equals_;
 
  public:
   Params(const string & base_name) :
@@ -71,7 +72,8 @@ class Params {
     generate_has_(false),
     java_enum_style_(false),
     optional_field_accessors_(false),
-    use_reference_types_for_primitives_(false) {
+    use_reference_types_for_primitives_(false),
+    generate_equals_(false) {
   }
 
   const string& base_name() const {
@@ -186,6 +188,13 @@ class Params {
   bool use_reference_types_for_primitives() const {
     return use_reference_types_for_primitives_;
   }
+
+  void set_generate_equals(bool value) {
+    generate_equals_ = value;
+  }
+  bool generate_equals() const {
+    return generate_equals_;
+  }
 };
 
 }  // namespace javanano
diff --git a/src/google/protobuf/compiler/javanano/javanano_primitive_field.cc b/src/google/protobuf/compiler/javanano/javanano_primitive_field.cc
index 0f7512a..cc5fd45 100644
--- a/src/google/protobuf/compiler/javanano/javanano_primitive_field.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_primitive_field.cc
@@ -404,8 +404,102 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
   }
 }
 
-string PrimitiveFieldGenerator::GetBoxedType() const {
-  return BoxedPrimitiveTypeName(GetJavaType(descriptor_));
+void PrimitiveFieldGenerator::
+GenerateEqualsCode(io::Printer* printer) const {
+  // We define equality as serialized form equality. If generate_has(),
+  // then if the field value equals the default value in both messages,
+  // but one's 'has' field is set and the other's is not, the serialized
+  // forms are different and we should return false.
+  JavaType java_type = GetJavaType(descriptor_);
+  if (java_type == JAVATYPE_BYTES) {
+    printer->Print(variables_,
+      "if (!java.util.Arrays.equals(this.$name$, other.$name$)");
+    if (params_.generate_has()) {
+      printer->Print(variables_,
+        "\n"
+        "    || (java.util.Arrays.equals(this.$name$, $default$)\n"
+        "        && this.has$capitalized_name$ != other.has$capitalized_name$)");
+    }
+    printer->Print(") {\n"
+      "  return false;\n"
+      "}\n");
+  } else if (java_type == JAVATYPE_STRING
+      || params_.use_reference_types_for_primitives()) {
+    printer->Print(variables_,
+      "if (this.$name$ == null) {\n"
+      "  if (other.$name$ != null) {\n"
+      "    return false;\n"
+      "  }\n"
+      "} else if (!this.$name$.equals(other.$name$)");
+    if (params_.generate_has()) {
+      printer->Print(variables_,
+        "\n"
+        "    || (this.$name$.equals($default$)\n"
+        "        && this.has$capitalized_name$ != other.has$capitalized_name$)");
+    }
+    printer->Print(") {\n"
+      "  return false;\n"
+      "}\n");
+  } else {
+    printer->Print(variables_,
+      "if (this.$name$ != other.$name$");
+    if (params_.generate_has()) {
+      printer->Print(variables_,
+        "\n"
+        "    || (this.$name$ == $default$\n"
+        "        && this.has$capitalized_name$ != other.has$capitalized_name$)");
+    }
+    printer->Print(") {\n"
+      "  return false;\n"
+      "}\n");
+  }
+}
+
+void PrimitiveFieldGenerator::
+GenerateHashCodeCode(io::Printer* printer) const {
+  JavaType java_type = GetJavaType(descriptor_);
+  if (java_type == JAVATYPE_BYTES) {
+    printer->Print(variables_,
+      "result = 31 * result + java.util.Arrays.hashCode(this.$name$);\n");
+  } else if (java_type == JAVATYPE_STRING
+      || params_.use_reference_types_for_primitives()) {
+    printer->Print(variables_,
+      "result = 31 * result\n"
+      "    + (this.$name$ == null ? 0 : this.$name$.hashCode());\n");
+  } else {
+    switch (java_type) {
+      // For all Java primitive types below, the hash codes match the
+      // results of BoxedType.valueOf(primitiveValue).hashCode().
+      case JAVATYPE_INT:
+        printer->Print(variables_,
+          "result = 31 * result + this.$name$;\n");
+        break;
+      case JAVATYPE_LONG:
+        printer->Print(variables_,
+          "result = 31 * result\n"
+          "    + (int) (this.$name$ ^ (this.$name$ >>> 32));\n");
+        break;
+      case JAVATYPE_FLOAT:
+        printer->Print(variables_,
+          "result = 31 * result\n"
+          "    + java.lang.Float.floatToIntBits(this.$name$);\n");
+        break;
+      case JAVATYPE_DOUBLE:
+        printer->Print(variables_,
+          "{\n"
+          "  long v = java.lang.Double.doubleToLongBits(this.$name$);\n"
+          "  result = 31 * result + (int) (v ^ (v >>> 32));\n"
+          "}\n");
+        break;
+      case JAVATYPE_BOOLEAN:
+        printer->Print(variables_,
+          "result = 31 * result + (this.$name$ ? 1231 : 1237);\n");
+        break;
+      default:
+        GOOGLE_LOG(ERROR) << "unknown java type for primitive field";
+        break;
+    }
+  }
 }
 
 // ===================================================================
@@ -483,8 +577,87 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
     "}\n");
 }
 
-string AccessorPrimitiveFieldGenerator::GetBoxedType() const {
-  return BoxedPrimitiveTypeName(GetJavaType(descriptor_));
+void AccessorPrimitiveFieldGenerator::
+GenerateEqualsCode(io::Printer* printer) const {
+  switch (GetJavaType(descriptor_)) {
+    // For all Java primitive types below, the hash codes match the
+    // results of BoxedType.valueOf(primitiveValue).hashCode().
+    case JAVATYPE_INT:
+    case JAVATYPE_LONG:
+    case JAVATYPE_FLOAT:
+    case JAVATYPE_DOUBLE:
+    case JAVATYPE_BOOLEAN:
+      printer->Print(variables_,
+        "if ($different_has$\n"
+        "    || $name$_ != other.$name$_) {\n"
+        "  return false;\n"
+        "}\n");
+      break;
+    case JAVATYPE_STRING:
+      // Accessor style would guarantee $name$_ non-null
+      printer->Print(variables_,
+        "if ($different_has$\n"
+        "    || !$name$_.equals(other.$name$_)) {\n"
+        "  return false;\n"
+        "}\n");
+      break;
+    case JAVATYPE_BYTES:
+      // Accessor style would guarantee $name$_ non-null
+      printer->Print(variables_,
+        "if ($different_has$\n"
+        "    || !java.util.Arrays.equals($name$_, other.$name$_)) {\n"
+        "  return false;\n"
+        "}\n");
+      break;
+    default:
+      GOOGLE_LOG(ERROR) << "unknown java type for primitive field";
+      break;
+  }
+}
+
+void AccessorPrimitiveFieldGenerator::
+GenerateHashCodeCode(io::Printer* printer) const {
+  switch (GetJavaType(descriptor_)) {
+    // For all Java primitive types below, the hash codes match the
+    // results of BoxedType.valueOf(primitiveValue).hashCode().
+    case JAVATYPE_INT:
+      printer->Print(variables_,
+        "result = 31 * result + $name$_;\n");
+      break;
+    case JAVATYPE_LONG:
+      printer->Print(variables_,
+        "result = 31 * result + (int) ($name$_ ^ ($name$_ >>> 32));\n");
+      break;
+    case JAVATYPE_FLOAT:
+      printer->Print(variables_,
+        "result = 31 * result +\n"
+        "    java.lang.Float.floatToIntBits($name$_);\n");
+      break;
+    case JAVATYPE_DOUBLE:
+      printer->Print(variables_,
+        "{\n"
+        "  long v = java.lang.Double.doubleToLongBits($name$_);\n"
+        "  result = 31 * result + (int) (v ^ (v >>> 32));\n"
+        "}\n");
+      break;
+    case JAVATYPE_BOOLEAN:
+      printer->Print(variables_,
+        "result = 31 * result + ($name$_ ? 1231 : 1237);\n");
+      break;
+    case JAVATYPE_STRING:
+      // Accessor style would guarantee $name$_ non-null
+      printer->Print(variables_,
+        "result = 31 * result + $name$_.hashCode();\n");
+      break;
+    case JAVATYPE_BYTES:
+      // Accessor style would guarantee $name$_ non-null
+      printer->Print(variables_,
+        "result = 31 * result + java.util.Arrays.hashCode($name$_);\n");
+      break;
+    default:
+      GOOGLE_LOG(ERROR) << "unknown java type for primitive field";
+      break;
+  }
 }
 
 // ===================================================================
@@ -629,8 +802,20 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
     "}\n");
 }
 
-string RepeatedPrimitiveFieldGenerator::GetBoxedType() const {
-  return BoxedPrimitiveTypeName(GetJavaType(descriptor_));
+void RepeatedPrimitiveFieldGenerator::
+GenerateEqualsCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "if (!com.google.protobuf.nano.InternalNano.equals(\n"
+    "    this.$name$, other.$name$)) {\n"
+    "  return false;\n"
+    "}\n");
+}
+
+void RepeatedPrimitiveFieldGenerator::
+GenerateHashCodeCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "result = 31 * result\n"
+    "    + com.google.protobuf.nano.InternalNano.hashCode(this.$name$);\n");
 }
 
 }  // namespace javanano
diff --git a/src/google/protobuf/compiler/javanano/javanano_primitive_field.h b/src/google/protobuf/compiler/javanano/javanano_primitive_field.h
index b42e2f3..2d2b268 100644
--- a/src/google/protobuf/compiler/javanano/javanano_primitive_field.h
+++ b/src/google/protobuf/compiler/javanano/javanano_primitive_field.h
@@ -55,8 +55,8 @@ class PrimitiveFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
-
-  string GetBoxedType() const;
+  void GenerateEqualsCode(io::Printer* printer) const;
+  void GenerateHashCodeCode(io::Printer* printer) const;
 
  private:
   void GenerateSerializationConditional(io::Printer* printer) const;
@@ -79,8 +79,8 @@ class AccessorPrimitiveFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
-
-  string GetBoxedType() const;
+  void GenerateEqualsCode(io::Printer* printer) const;
+  void GenerateHashCodeCode(io::Printer* printer) const;
 
  private:
   const FieldDescriptor* descriptor_;
@@ -100,8 +100,8 @@ class RepeatedPrimitiveFieldGenerator : public FieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
-
-  string GetBoxedType() const;
+  void GenerateEqualsCode(io::Printer* printer) const;
+  void GenerateHashCodeCode(io::Printer* printer) const;
 
  private:
   void GenerateRepeatedDataSizeCode(io::Printer* printer) const;