has good test coverage, so look at some existing tests if you're unsure
     how to go about it.
  2. All contributions must be licensed Apache 2.0 and all files must have a
     copy of the boilerplate license comment (can be copied from an existing
     file).
  3. Files should be formatted according to Google's [Java style guide][].
  4. Please squash all commits for a change into a single commit (this can be

   *
   * <p>This method is called {@code murmur3_32_fixed} because it fixes a bug in the {@code
   * HashFunction} returned by the original {@code murmur3_32} method.
   *
   * @since 31.0
   */
  public static HashFunction murmur3_32_fixed() {
    return Murmur3_32HashFunction.MURMUR3_32_FIXED;
  }

  /**
   * Returns a hash function implementing the <a

 * @param <K> the type of keys used by the maps under test
 * @param <V> the type of mapped values used the maps under test
 * @author George van den Driessche
 */
// TODO: Descriptive assertion messages, with hints as to probable fixes.
// TODO: Add another constructor parameter indicating whether the class under test is ordered, and
// check the order if so.
// TODO: Refactor to share code with SetTestBuilder etc.
@GwtCompatible

 * @param <K> the type of keys used by the maps under test
 * @param <V> the type of mapped values used the maps under test
 * @author George van den Driessche
 */
// TODO: Descriptive assertion messages, with hints as to probable fixes.
// TODO: Add another constructor parameter indicating whether the class under test is ordered, and
// check the order if so.
// TODO: Refactor to share code with SetTestBuilder etc.
@GwtCompatible

     * including in MapRetrievalCache, so I'm not sure why this one is different. I did at least
     * confirm that my change to MapIteratorCache fixes the TSAN error in the (larger) test it was
     * originally reported in.
     */
    for (Future<?> future : futures.build()) {
      future.get();
    }
    executor.shutdown();
  }

     * including in MapRetrievalCache, so I'm not sure why this one is different. I did at least
     * confirm that my change to MapIteratorCache fixes the TSAN error in the (larger) test it was
     * originally reported in.
     */
    for (Future<?> future : futures.build()) {
      future.get();
    }
    executor.shutdown();
  }

   * can suppress it with {@code FeatureSpecificTestSuiteBuilder.suppressing()} until <a
   * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5045147">Sun bug 5045147</a> is fixed.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection
  public static Method getPutAllNullKeyUnsupportedMethod() {
    return Helpers.getMethod(MapPutAllTester.class, "testPutAll_nullKeyUnsupported");
  }

   * suppress it with {@code FeatureSpecificTestSuiteBuilder.suppressing()} until <a
   * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5045147">Sun bug 5045147</a> is fixed.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection
  public static Method getAddAllNullUnsupportedMethod() {
    return Helpers.getMethod(CollectionAddAllTester.class, "testAddAll_nullUnsupported");
  }

            <tag>
              <name>spec</name>
              <placement>X</placement>
            </tag>
          </tags>

          <!-- TODO(cpovirk): Move this to the parent after making the package-list files available there. -->
          <!-- We add the link ourselves, both so that we can choose Java 9 over the version that -source suggests and so that we can solve the JSR305 problem described below. -->

  }

  @VisibleForTesting
  static class NonSerializableMemoizingSupplier<T extends @Nullable Object> implements Supplier<T> {
    @SuppressWarnings("UnnecessaryLambda") // Must be a fixed singleton object
    private static final Supplier<Void> SUCCESSFULLY_COMPUTED =
        () -> {
          throw new IllegalStateException(); // Should never get called.
        };