private static final Collection<Integer> EMPTY_COLLECTION = Arrays.<Integer>asList();

  private static final Collection<Integer> SOME_COLLECTION = Arrays.asList(0, 1, 1);

  private static final Iterable<Integer> SOME_ITERABLE =
      new Iterable<Integer>() {
        @Override
        public Iterator<Integer> iterator() {
          return SOME_COLLECTION.iterator();
        }
      };

  }

  private static <E extends @Nullable Object> Collection<E> typePreservingCollection(
      Collection<E> collection, @CheckForNull Object mutex) {
    if (collection instanceof SortedSet) {
      return sortedSet((SortedSet<E>) collection, mutex);
    }
    if (collection instanceof Set) {
      return set((Set<E>) collection, mutex);
    }
    if (collection instanceof List) {

    checkNotNull(collection);
    return (collection instanceof EnumSet)
        ? EnumSet.complementOf((EnumSet<E>) collection)
        : makeComplementByHand(collection, type);
  }

  @J2ktIncompatible
  @GwtIncompatible
  private static <E extends Enum<E>> EnumSet<E> makeComplementByHand(
      Collection<E> collection, Class<E> type) {
    EnumSet<E> result = EnumSet.allOf(type);

      Collection<V> collection) {
    if (collection instanceof SortedSet) {
      return Collections.unmodifiableSortedSet((SortedSet<V>) collection);
    } else if (collection instanceof Set) {
      return Collections.unmodifiableSet((Set<V>) collection);
    } else if (collection instanceof List) {
      return Collections.unmodifiableList((List<V>) collection);
    }

import java.util.function.Function;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link NavigableMap} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * <p><b>Warning:</b> as with any sorted collection, you are strongly advised not to use a {@link

                  }

                  @Override
                  public boolean removeAll(Collection<?> c) {
                    return Iterators.removeAll(iterator(), c);
                  }

                  @Override
                  public boolean retainAll(Collection<?> c) {
                    return Iterators.retainAll(iterator(), c);
                  }
                };

   * IllegalArgumentException} is thrown when the collection operation is performed. (This differs
   * from the {@code Collector} returned by {@link Collectors#toMap(Function, Function)}, which
   * throws an {@code IllegalStateException}.)
   *
   * @since 21.0
   */
  public static <T extends @Nullable Object, K, V>
      Collector<T, ?, ImmutableSortedMap<K, V>> toImmutableSortedMap(
          Comparator<? super K> comparator,

  /**
   * Adds all elements in {@code iterator} to {@code collection}. The iterator will be left
   * exhausted: its {@code hasNext()} method will return {@code false}.
   *
   * @return {@code true} if {@code collection} was modified as a result of this operation
   */
  @CanIgnoreReturnValue
  public static <T extends @Nullable Object> boolean addAll(
      Collection<T> addTo, Iterator<? extends T> iterator) {
    checkNotNull(addTo);

      Iterable<? extends ListenableFuture<? extends T>> futures) {
    final Collection<ListenableFuture<? extends T>> collection;
    if (futures instanceof Collection) {
      collection = (Collection<ListenableFuture<? extends T>>) futures;
    } else {
      collection = ImmutableList.copyOf(futures);
    }
    return (ListenableFuture<? extends T>[]) collection.toArray(new ListenableFuture<?>[0]);
  }

  @Override
  public Set<K> keySet() {
    Set<K> ks = keySet;
    return (ks != null) ? ks : (keySet = new KeySet());
  }

  @LazyInit @CheckForNull transient Collection<V> values;

  @Override
  public Collection<V> values() {
    Collection<V> vs = values;
    return (vs != null) ? vs : (values = new Values());
  }

  @LazyInit @CheckForNull transient Set<Entry<K, V>> entrySet;

  @Override