Object writeReplace() {
    return new SerializedForm<V>(map);
  }

  @GwtIncompatible // serialization
  @J2ktIncompatible
  private static class SerializedForm<V> implements Serializable {
    final ImmutableMap<?, V> map;

    SerializedForm(ImmutableMap<?, V> map) {
      this.map = map;
    }

    Object readResolve() {
      return map.values();
    }

    COPY_OF_MAP {
      @Override
      public Map<Object, Object> create(List<?> keys) {
        Map<Object, Object> sourceMap = new LinkedHashMap<>();
        for (Object k : keys) {
          if (sourceMap.put(k, "dummy value") != null) {
            throw new UnsupportedOperationException("duplicate key");
          }
        }
        return ImmutableMap.copyOf(sourceMap);
      }

  }

  @Override
  protected Map<String, Collection<Integer>> makeEmptyMap() {
    Map<String, Integer> map = Maps.newHashMap();
    return Multimaps.forMap(map).asMap();
  }

  @Override
  protected Map<String, Collection<Integer>> makePopulatedMap() {
    Map<String, Integer> map = Maps.newHashMap();
    map.put("foo", 1);
    map.put("bar", 2);
    map.put("cow", 3);
    return Multimaps.forMap(map).asMap();

    @Override
    protected Map<AnEnum, String> create(Entry<AnEnum, String>[] entries) {
      Map<AnEnum, String> map = Maps.newHashMap();
      for (Entry<AnEnum, String> entry : entries) {
        // checkArgument(!map.containsKey(entry.getKey()));
        map.put(entry.getKey(), entry.getValue());
      }
      return Maps.immutableEnumMap(map);
    }
  }

    // Hack around K not being a subtype of Comparable.
    // Unsafe, see ImmutableSortedSetFauxverideShim.
    @SuppressWarnings("unchecked")
    Ordering<K> naturalOrder = (Ordering<K>) NATURAL_ORDER;
    return copyOfInternal(map, naturalOrder);
  }

  /**
   * Returns an immutable map containing the same entries as {@code map}, with keys sorted by the

   * {@code EnumHashBiMap} or an {@link EnumBiMap}, the new bimap has the same key type as the input
   * bimap. Otherwise, the specified map must contain at least one mapping, in order to determine
   * the key type.
   *
   * @param map the map whose mappings are to be placed in this map

      ImmutableMap<K, V> map = super.buildOrThrow();
      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) {

    final ConcurrentMap<?, ?> map;

    AbstractCacheSet(ConcurrentMap<?, ?> map) {
      this.map = map;
    }

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

    @Override
    public boolean isEmpty() {
      return map.isEmpty();
    }

    @Override
    public void clear() {
      map.clear();
    }
  }

  public static <K, V> ImmutableMap<K, V> copyOf(Map<? extends K, ? extends V> map) {
    if ((map instanceof ImmutableMap) && !(map instanceof ImmutableSortedMap)) {
      @SuppressWarnings("unchecked") // safe since map is not writable
      ImmutableMap<K, V> kvMap = (ImmutableMap<K, V>) map;
      return kvMap;
    } else if (map instanceof EnumMap) {
      EnumMap<?, ?> enumMap = (EnumMap<?, ?>) map;

     * map.remove(x)} returns the same value which {@code map.get(x)} did immediately beforehand.
     */
    @Override
    public void testRemove() {
      final Map<String, Map<Integer, Character>> map;
      final String keyToRemove;
      try {
        map = makePopulatedMap();
      } catch (UnsupportedOperationException e) {
        return;
      }
      keyToRemove = map.keySet().iterator().next();