* #iterator} to forward to this implementation.
   *
   * @since 7.0
   */
  protected Iterator<E> standardIterator() {
    return Multisets.iteratorImpl(this);
  }

  /**
   * A sensible, albeit inefficient, definition of {@link #size} in terms of {@link #entrySet}. If
   * you override {@link #entrySet}, you may wish to override {@link #size} to forward to this
   * implementation.
   *

  private static final class InverseSerializedForm<K, V> implements Serializable {
    private final ImmutableBiMap<K, V> forward;

    InverseSerializedForm(ImmutableBiMap<K, V> forward) {
      this.forward = forward;
    }

    Object readResolve() {
      return forward.inverse();
    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 1;
  }

    private final HashBiMap<K, V> forward;

    Inverse(HashBiMap<K, V> forward) {
      this.forward = forward;
    }

    @Override
    public int size() {
      return forward.size;
    }

    @Override
    public boolean containsKey(@Nullable Object key) {
      return forward.containsValue(key);
    }

    @Override

   * forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardFirstEntry() {
    return Iterables.<@Nullable Entry<K, V>>getFirst(entrySet(), null);
  }

  /**
   * A sensible definition of {@link #firstKey} in terms of {@code firstEntry}. If you override
   * {@code firstEntry}, you may wish to override {@code firstKey} to forward to this
   * implementation.
   */

   * forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardFirstEntry() {
    return Iterables.<@Nullable Entry<K, V>>getFirst(entrySet(), null);
  }

  /**
   * A sensible definition of {@link #firstKey} in terms of {@code firstEntry}. If you override
   * {@code firstEntry}, you may wish to override {@code firstKey} to forward to this
   * implementation.
   */

   * forward to this implementation.
   *
   * @since 7.0
   */
  protected int standardHashCode() {
    return Sets.hashCodeImpl(entrySet());
  }

  /**
   * A sensible definition of {@link #toString} in terms of the {@code iterator} method of {@link
   * #entrySet}. If you override {@link #entrySet}, you may wish to override {@link #toString} to
   * forward to this implementation.
   *

            Currency.FRANC, Country.SWITZERLAND);
    EnumBiMap<Currency, Country> bimap = EnumBiMap.create(map);

    // forward map ordered by currency
    assertThat(bimap.keySet())
        .containsExactly(Currency.DOLLAR, Currency.FRANC, Currency.PESO)
        .inOrder();
    // forward map ordered by currency (even for country values)
    assertThat(bimap.values())

            Currency.FRANC, Country.SWITZERLAND);
    EnumBiMap<Currency, Country> bimap = EnumBiMap.create(map);

    // forward map ordered by currency
    assertThat(bimap.keySet())
        .containsExactly(Currency.DOLLAR, Currency.FRANC, Currency.PESO)
        .inOrder();
    // forward map ordered by currency (even for country values)
    assertThat(bimap.values())

 *   <li>Extend this class and implement its {@link #doForward} and {@link #doBackward} methods.
 * </ul>
 *
 * <p>Using a converter:
 *
 * <ul>
 *   <li>Convert one instance in the "forward" direction using {@code converter.convert(a)}.
 *   <li>Convert multiple instances "forward" using {@code converter.convertAll(as)}.

            return new ForwardingRunnable(runnable) {
              @Override
              public void run() {}
            };
          }
        },
        "run()",
        "Failed to forward");
  }

  public void testRedundantForwarding() {
    assertFailure(
        Runnable.class,
        new Function<Runnable, Runnable>() {
          @Override