@Override
        public boolean removeAll(Collection<?> c) {
          return delegate.keySet().removeAll(c);
        }

        @Override
        public boolean retainAll(Collection<?> c) {
          return delegate.keySet().retainAll(c);
        }
      };
    }

    @Override
    public Collection<V> values() {
      return new ForwardingCollection<V>() {
        @Override

  }

  @Override
  public void testEntrySetRetainAllNullFromEmpty() {
    try {
      super.testEntrySetRetainAllNullFromEmpty();
    } catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().retainAll(null) doesn't throws NPE.
    }
  }

  @Override
  public void testKeySetRemoveAllNullFromEmpty() {
    try {
      super.testKeySetRemoveAllNullFromEmpty();
    } catch (RuntimeException tolerated) {

        @Override
        public boolean removeAll(Collection<?> c) {
          return delegate.keySet().removeAll(c);
        }

        @Override
        public boolean retainAll(Collection<?> c) {
          return delegate.keySet().retainAll(c);
        }
      };
    }

    @Override
    public Collection<V> values() {
      return new ForwardingCollection<V>() {
        @Override

  }

  @Override
  public void testEntrySetRetainAllNullFromEmpty() {
    try {
      super.testEntrySetRetainAllNullFromEmpty();
    } catch (RuntimeException tolerated) {
      // GWT's TreeMap.entrySet().retainAll(null) doesn't throws NPE.
    }
  }

  @Override
  public void testKeySetRemoveAllNullFromEmpty() {
    try {
      super.testKeySetRemoveAllNullFromEmpty();
    } catch (RuntimeException tolerated) {

        }

        @Override
        public boolean removeAll(Collection<?> c) {
          return removeEntriesIf(Maps.<K>keyPredicateOnEntries(in(c)));
        }

        @Override
        public boolean retainAll(Collection<?> c) {
          return removeEntriesIf(Maps.<K>keyPredicateOnEntries(not(in(c))));
        }

        @Override
        public boolean remove(@CheckForNull Object o) {

  }

  /** An implementation of {@link Multiset#retainAll}. */
  static boolean retainAllImpl(Multiset<?> self, Collection<?> elementsToRetain) {
    checkNotNull(elementsToRetain);
    Collection<?> collection =
        (elementsToRetain instanceof Multiset)
            ? ((Multiset<?>) elementsToRetain).elementSet()
            : elementsToRetain;

    return self.elementSet().retainAll(collection);
  }

  }

  public void testRetainAll_collection() {
    List<String> list = newArrayList("a", "b", "c", "d", "e");
    assertTrue(Iterables.retainAll(list, newArrayList("b", "d", "f")));
    assertEquals(newArrayList("b", "d"), list);
    assertFalse(Iterables.retainAll(list, newArrayList("b", "e", "d")));
    assertEquals(newArrayList("b", "d"), list);
  }

  public void testRetainAll_iterable() {

  public static <E extends @Nullable Object> Collection<E> filter(
      Collection<E> unfiltered, Predicate<? super E> predicate) {
    if (unfiltered instanceof FilteredCollection) {
      // Support clear(), removeAll(), and retainAll() when filtering a filtered
      // collection.
      return ((FilteredCollection<E>) unfiltered).createCombined(predicate);
    }

    return new FilteredCollection<>(checkNotNull(unfiltered), checkNotNull(predicate));

    @Override
    public boolean removeAll(Collection<?> c) {
      return removeAllImpl(this, c);
    }

    @Override
    public boolean retainAll(Collection<?> c) {
      return super.retainAll(checkNotNull(c)); // GWT compatibility
    }
  }

  /**
   * Returns an immutable set instance containing the given enum elements. Internally, the returned

                  }

                  @Override
                  public boolean retainAll(Collection<?> c) {
                    return Iterators.retainAll(iterator(), c);
                  }
                };
              }
            })
        .named("ArrayList with Iterators.removeAll and retainAll")
        .withFeatures(