public ImmutableMultiset<K> keys() {
    return (ImmutableMultiset<K>) super.keys();
  }

  @Override
  ImmutableMultiset<K> createKeys() {
    return new Keys();
  }

  @SuppressWarnings("serial") // Uses writeReplace, not default serialization
  @WeakOuter
  private final class Keys extends ImmutableMultiset<K> {
    @Override
    public boolean contains(@Nullable Object object) {

px;--breakpoint-lg:992px;--breakpoint-xl:1200px;--font-family-sans-serif:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,"Noto Sans","Liberation Sans",sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji";--font-family-monospace:SFMono-Regular,Menlo,Monaco,Consolas,"Liberation Mono","Courier New",monospace}*,::after,::before{box-sizing:border-box}html{font-family:sans-serif;line-height:1.15;-webkit-text-size-adjust:100%;-webkit-tap-highlig...

/**
 * A {@link Set} whose contents will never change, with many other important properties detailed at
 * {@link ImmutableCollection}.
 *
 * @since 2.0
 */
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
public abstract class ImmutableSet<E> extends ImmutableCollection<E> implements Set<E> {
  static final int SPLITERATOR_CHARACTERISTICS =

          @Override
          public Iterator<Integer> iterator() {
            return asList(0, 1).iterator();
          }
        };
    assertEquals(2, Iterables.size(iterable));
  }

  @SuppressWarnings("serial")
  public void testSize_collection_doesntIterate() {
    List<Integer> nums = asList(1, 2, 3, 4, 5);
    List<Integer> collection =
        new ArrayList<Integer>(nums) {
          @Override

   * @since 7.0
   */
  public static List<Character> charactersOf(CharSequence sequence) {
    return new CharSequenceAsList(checkNotNull(sequence));
  }

  @SuppressWarnings("serial") // serialized using ImmutableList serialization
  private static final class StringAsImmutableList extends ImmutableList<Character> {

    private final String string;

    StringAsImmutableList(String string) {

 * @author Louis Wasserman
 * @since 2.0 (implements {@code NavigableSet} since 12.0)
 */
// TODO(benyu): benchmark and optimize all creation paths, which are a mess now
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
public abstract class ImmutableSortedSet<E> extends ImmutableSet<E>
    implements NavigableSet<E>, SortedIterable<E> {
  /**

          @Override
          public Iterator<Integer> iterator() {
            return asList(0, 1).iterator();
          }
        };
    assertEquals(2, Iterables.size(iterable));
  }

  @SuppressWarnings("serial")
  public void testSize_collection_doesntIterate() {
    List<Integer> nums = asList(1, 2, 3, 4, 5);
    List<Integer> collection =
        new ArrayList<Integer>(nums) {
          @Override

 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 * @since 2.0
 */
@DoNotMock("Use ImmutableMap.of or another implementation")
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
public abstract class ImmutableMap<K, V> implements Map<K, V>, Serializable {

  /**
   * Returns a {@link Collector} that accumulates elements into an {@code ImmutableMap} whose keys

  }

  /**
   * Returns a synchronized (thread-safe) navigable set backed by the specified navigable set. In
   * order to guarantee serial access, it is critical that <b>all</b> access to the backing
   * navigable set is accomplished through the returned navigable set (or its views).
   *

 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 * @since 2.0
 */
@DoNotMock("Use ImmutableMap.of or another implementation")
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
public abstract class ImmutableMap<K, V> implements Map<K, V>, Serializable {

  /**
   * Returns a {@link Collector} that accumulates elements into an {@code ImmutableMap} whose keys