}
    },
    FORCE_JDK {
      @Override
      public ImmutableBiMap<Object, Object> create(List<Entry<?, ?>> entries) {
        return ImmutableBiMap.builder().putAll(entries).buildJdkBacked();
      }
    };

    @CanIgnoreReturnValue
    public abstract ImmutableBiMap<Object, Object> create(List<Entry<?, ?>> entries);
  }

      if (map.isEmpty()) {
        return of();
      }
      return new RegularImmutableBiMap<K, V>(super.buildOrThrow());
    }

    @Override
    ImmutableBiMap<K, V> buildJdkBacked() {
      return build();
    }
  }

  public static <K, V> ImmutableBiMap<K, V> copyOf(Map<? extends K, ? extends V> map) {
    if (map instanceof ImmutableBiMap) {

      throw new UnsupportedOperationException("Not supported for bimaps");
    }

    @Override
    @VisibleForTesting
    ImmutableBiMap<K, V> buildJdkBacked() {
      checkState(
          valueComparator == null,
          "buildJdkBacked is for tests only, doesn't support orderEntriesByValue");
      switch (size) {
        case 0:
          return of();
        case 1:

     * Builder}.
     */
    @Override
    public ImmutableMultiset<E> build() {
      return copyOf(contents);
    }

    @VisibleForTesting
    ImmutableMultiset<E> buildJdkBacked() {
      if (contents.isEmpty()) {
        return of();
      }
      return JdkBackedImmutableMultiset.create(contents.entrySet());
    }
  }

                new TestStringMultisetGenerator() {
                  @Override
                  protected Multiset<String> create(String[] elements) {
                    return ImmutableMultiset.<String>builder().add(elements).buildJdkBacked();
                  }
                })
            .named("ImmutableMultiset [JDK backed]")
            .withFeatures(
                CollectionSize.ANY,