* @throws NullPointerException if any key or value in {@code map} is null
   */
  public static <K, V> ImmutableMap<K, V> copyOf(Map<? extends K, ? extends V> map) {
    if ((map instanceof ImmutableMap) && !(map instanceof SortedMap)) {
      @SuppressWarnings("unchecked") // safe since map is not writable
      ImmutableMap<K, V> kvMap = (ImmutableMap<K, V>) map;
      if (!kvMap.isPartialView()) {
        return kvMap;
      }
    }

     * java.util.LinkedHashMap LinkedHashMap} and {@link ImmutableMap#copyOf(Map)} rather than
     * {@code ImmutableMap.Builder}.
     *
     * @since 31.1
     */
    public ImmutableMap<K, V> buildKeepingLast() {
      return build(false);
    }

    @VisibleForTesting // only for testing JDK backed implementation
    ImmutableMap<K, V> buildJdkBacked() {
      checkState(

        ImmutableMap::copyOf);
  }

  @SuppressWarnings("unchecked") // An empty map works for all types.
  public static <K, V> ImmutableMap<K, V> of() {
    return (ImmutableMap<K, V>) RegularImmutableMap.EMPTY;
  }

  public static <K, V> ImmutableMap<K, V> of(K k1, V v1) {
    return ImmutableBiMap.of(k1, v1);
  }

  public static <K, V> ImmutableMap<K, V> of(K k1, V v1, K k2, V v2) {

    };

    // used under GWT, etc., since the override of this method does not exist there
    ImmutableMap<Class<? extends Throwable>, Predicate<Throwable>> exceptions() {
      return ImmutableMap.of();
    }
  }

  private static final ImmutableMap<Class<? extends Throwable>, Predicate<Throwable>> INSTANCE_OF =
      ImmutableMap.<Class<? extends Throwable>, Predicate<Throwable>>builder()

          .put(ImmutableSortedSet.class, ImmutableSortedSet.of())
          .put(NavigableSet.class, Sets.unmodifiableNavigableSet(Sets.newTreeSet()))
          .put(Map.class, ImmutableMap.of())
          .put(ImmutableMap.class, ImmutableMap.of())
          .put(SortedMap.class, ImmutableSortedMap.of())
          .put(ImmutableSortedMap.class, ImmutableSortedMap.of())

import java.util.Map;

/**
 * GWt emulation of {@link RegularImmutableMap}.
 *
 * @author Hayward Chan
 */
final class RegularImmutableMap<K, V> extends ForwardingImmutableMap<K, V> {

  static final ImmutableMap<Object, Object> EMPTY = new RegularImmutableMap<Object, Object>();

  RegularImmutableMap(Map<? extends K, ? extends V> delegate) {
    super(delegate);
  }

 * to avoid code-size bloat.
 *
 * @author Hayward Chan
 */
final class ImmutableEnumMap<K, V> extends ForwardingImmutableMap<K, V> {
  static <K, V> ImmutableMap<K, V> asImmutable(Map<K, V> map) {
    for (Entry<K, V> entry : checkNotNull(map).entrySet()) {
      checkNotNull(entry.getKey());
      checkNotNull(entry.getValue());
    }
    return new ImmutableEnumMap<K, V>(map);

    new EqualsTester()
        .addEqualityGroup(
            ImmutableMap.of(),
            ImmutableMap.builder().buildOrThrow(),
            ImmutableMap.ofEntries(),
            map())
        .addEqualityGroup(
            ImmutableMap.of(1, 1),
            ImmutableMap.builder().put(1, 1).buildOrThrow(),
            ImmutableMap.ofEntries(entry(1, 1)),
            map(1, 1))
        .addEqualityGroup(

    unfiltered.put("four", 4);
    assertEquals(ImmutableMap.of("two", 2, "three", 3, "four", 4), unfiltered);
    assertEquals(ImmutableMap.of("three", 3, "four", 4), filtered);

    unfiltered.remove("three");
    assertEquals(ImmutableMap.of("two", 2, "four", 4), unfiltered);
    assertEquals(ImmutableMap.of("four", 4), filtered);

    unfiltered.clear();
    assertEquals(ImmutableMap.of(), unfiltered);

    assertEquals(ImmutableMap.of(1, 'a', 3, 'c'), row);
    assertEquals(ImmutableMap.of(3, 'c'), subRow);
    table.remove("foo", 3);
    assertEquals(ImmutableMap.of(1, 'a'), row);
    assertEquals(ImmutableMap.of(), subRow);
    table.remove("foo", 1);
    assertEquals(ImmutableMap.of(), row);
    assertEquals(ImmutableMap.of(), subRow);
    table.put("foo", 2, 'b');