* invoke methods, they invoke methods on the {@code ForwardingMultimap}.
 *
 * @author Robert Konigsberg
 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingObject implements Multimap<K, V> {

  /** Constructor for use by subclasses. */
  protected ForwardingMultimap() {}

  @Override

 * invoke methods, they invoke methods on the {@code ForwardingMultimap}.
 *
 * @author Robert Konigsberg
 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingObject implements Multimap<K, V> {

  /** Constructor for use by subclasses. */
  protected ForwardingMultimap() {}

  @Override

 *
 * @author Kurt Alfred Kluever
 * @since 3.0
 */
@GwtCompatible
public abstract class ForwardingSetMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingMultimap<K, V> implements SetMultimap<K, V> {
  /** Constructor for use by subclasses. */
  public ForwardingSetMultimap() {}

  @Override
  protected abstract SetMultimap<K, V> delegate();

  @Override

   * populate a map to be passed to {@link Multimaps#forMap(Map)}. All tests should run against the
   * result of {@link #build()}.
   */
  private static final class PopulatableMapAsMultimap<K, V> extends ForwardingMultimap<K, V> {
    final Map<K, V> map;
    final SetMultimap<K, V> unusableDelegate;

    static <K, V> PopulatableMapAsMultimap<K, V> create() {
      return new PopulatableMapAsMultimap<>();
    }

    return checkNotNull(delegate);
  }

  private static class UnmodifiableMultimap<K extends @Nullable Object, V extends @Nullable Object>
      extends ForwardingMultimap<K, V> implements Serializable {
    final Multimap<K, V> delegate;
    @LazyInit transient @Nullable Collection<Entry<K, V>> entries;
    @LazyInit transient @Nullable Multiset<K> keys;

    return checkNotNull(delegate);
  }

  private static class UnmodifiableMultimap<K extends @Nullable Object, V extends @Nullable Object>
      extends ForwardingMultimap<K, V> implements Serializable {
    final Multimap<K, V> delegate;
    @LazyInit transient @Nullable Collection<Entry<K, V>> entries;
    @LazyInit transient @Nullable Multiset<K> keys;