return false;
  }

  @LazyInit private transient @Nullable Collection<V> valuesView;

  @Override
  public Collection<V> values() {
    return (valuesView == null) ? valuesView = createValues() : valuesView;
  }

  Collection<V> createValues() {
    return new ValuesView();
  }

  @WeakOuter
  private final class ValuesView extends AbstractCollection<V> {
    @Override
    public int size() {