assertFalse(keys.remove(null));
      assertFalse(keys.remove(6));
      assertFalse(keys.remove(-6));
      assertFalse(keys.removeAll(asList(null, 0, 15, 1500)));
      assertFalse(keys.retainAll(asList(null, 0, 15, 1500)));
      checkEmpty(keys);
      checkEmpty(cache);
    }
  }

  public void testKeySet_remove() {
    for (LoadingCache<Object, Object> cache : caches()) {

    }
  }

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

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

    }
  }

  @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) {

import java.lang.reflect.Method;
import java.util.List;
import org.junit.Ignore;

/**
 * Tests for {@code Multiset#remove}, {@code Multiset.removeAll}, and {@code Multiset.retainAll} not
 * already covered by the corresponding Collection testers.
 *
 * @author Jared Levy
 */
@GwtCompatible(emulated = true)

  }

  @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(final Collection<?> c) {
            return parent.retainAll(c);
        }

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

        @Override
        public void clear() {
            parent.clear();
        }

        @Override

  }

  @CollectionSize.Require(ONE)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testEntrySet_retainAllPresent() {
    assertFalse(
        "multiset.entrySet.retainAll(presentEntry) returned false",
        getMultiset().entrySet().retainAll(singleton(Multisets.immutableEntry(e0(), 1))));
    assertTrue(
        "multiset doesn't contains element after retaining its entry",
        getMultiset().contains(e0()));
  }

      assertTrue(Thread.holdsLock(mutex));
      return delegate.addAll(collection);
    }

    @Override
    public boolean retainAll(Collection<?> collection) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.retainAll(collection);
    }

    @Override
    public void clear() {
      assertTrue(Thread.holdsLock(mutex));
      delegate.clear();
    }

      boolean didRemove = entrySet.retainAll(entriesToRetain);
      assertEquals(shouldRemove, didRemove);
      assertEquals(entriesToRetain.size(), map.size());
      for (Entry<K, V> entry : entriesToRetain) {
        assertTrue(entrySet.contains(entry));
      }
    } else {
      assertThrows(UnsupportedOperationException.class, () -> entrySet.retainAll(entriesToRetain));
    }
    assertInvariants(map);

        }

        @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) {