* can be used in the testers.
 *
 * @author Regina O'Dell
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public class MinimalSet<E extends @Nullable Object> extends MinimalCollection<E> implements Set<E> {

  @SuppressWarnings("unchecked") // empty Object[] as E[]
  public static <E extends @Nullable Object> MinimalSet<E> of(E... contents) {

    // "<String>" is required to work around a javac 1.5 bug.
    Collection<String> c = MinimalCollection.<String>of();
    Multiset<String> multiset = ImmutableSortedMultiset.copyOf(c);
    assertTrue(multiset.isEmpty());
  }

  public void testCopyOf_collection_oneElement() {
    Collection<String> c = MinimalCollection.of("a");
    Multiset<String> multiset = ImmutableSortedMultiset.copyOf(c);

      assertFalse(message, getMap().containsValue(null));
    } catch (NullPointerException tolerated) {
      // Tolerated
    }
  }

  @Override
  protected MinimalCollection<Entry<K, V>> createDisjointCollection() {
    return MinimalCollection.of(e3(), e4());
  }

  protected int getNumEntries() {
    return getNumElements();
  }

  protected Collection<Entry<K, V>> getSampleEntries(int howMany) {