@GwtCompatible(serializable = true, emulated = true)
@ElementTypesAreNonnullByDefault
public class ImmutableSetMultimap<K, V> extends ImmutableMultimap<K, V>
    implements SetMultimap<K, V> {
  /**
   * Returns a {@link Collector} that accumulates elements into an {@code ImmutableSetMultimap}
   * whose keys and values are the result of applying the provided mapping functions to the input
   * elements.
   *

        if (existing != null) {
          return existing;
        }
      }
      drainQueue();
      return created;
    }

    // N.B. Draining the queue is only necessary to ensure that we don't accumulate empty references
    // in the array. We could skip this if we decide we don't care about holding on to Reference
    // objects indefinitely.
    private void drainQueue() {
      Reference<? extends L> ref;

@GwtCompatible(serializable = true, emulated = true)
@ElementTypesAreNonnullByDefault
public final class ImmutableSortedMap<K, V> extends ImmutableMap<K, V>
    implements NavigableMap<K, V> {
  /**
   * Returns a {@link Collector} that accumulates elements into an {@code ImmutableSortedMap} whose
   * keys and values are the result of applying the provided mapping functions to the input
   * elements. The generated map is sorted by the specified comparator.
   *

 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Multisets {
  private Multisets() {}

  /**
   * Returns a {@code Collector} that accumulates elements into a multiset created via the specified
   * {@code Supplier}, whose elements are the result of applying {@code elementFunction} to the

 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Multisets {
  private Multisets() {}

  /**
   * Returns a {@code Collector} that accumulates elements into a multiset created via the specified
   * {@code Supplier}, whose elements are the result of applying {@code elementFunction} to the

@GwtCompatible(serializable = true, emulated = true)
@ElementTypesAreNonnullByDefault
public class ImmutableSetMultimap<K, V> extends ImmutableMultimap<K, V>
    implements SetMultimap<K, V> {
  /**
   * Returns a {@link Collector} that accumulates elements into an {@code ImmutableSetMultimap}
   * whose keys and values are the result of applying the provided mapping functions to the input
   * elements.
   *

@GwtCompatible(serializable = true, emulated = true)
@ElementTypesAreNonnullByDefault
public abstract class ImmutableBiMap<K, V> extends ImmutableMap<K, V> implements BiMap<K, V> {

  /**
   * Returns a {@link Collector} that accumulates elements into an {@code ImmutableBiMap} whose keys
   * and values are the result of applying the provided mapping functions to the input elements.
   * Entries appear in the result {@code ImmutableBiMap} in encounter order.
   *

    implements NavigableSet<E>, SortedIterable<E> {
  static final int SPLITERATOR_CHARACTERISTICS =
      ImmutableSet.SPLITERATOR_CHARACTERISTICS | Spliterator.SORTED;

  /**
   * Returns a {@code Collector} that accumulates the input elements into a new {@code
   * ImmutableSortedSet}, ordered by the specified comparator.
   *
   * <p>If the elements contain duplicates (according to the comparator), only the first duplicate

 *   <li>keys automatically wrapped in {@code WeakReference}
 *   <li>values automatically wrapped in {@code WeakReference} or {@code SoftReference}
 *   <li>notification of evicted (or otherwise removed) entries
 *   <li>accumulation of cache access statistics
 * </ul>
 *
 * <p>These features are all optional; caches can be created using all or none of them. By default,

@ElementTypesAreNonnullByDefault
public abstract class ImmutableList<E> extends ImmutableCollection<E>
    implements List<E>, RandomAccess {

  /**
   * Returns a {@code Collector} that accumulates the input elements into a new {@code
   * ImmutableList}, in encounter order.
   *
   * @since 21.0
   */
  public static <E> Collector<E, ?, ImmutableList<E>> toImmutableList() {