assertEquals(set.comparator(), copy.comparator());
  }

  @GwtIncompatible // SerializableTester
  public void testSingle_serialization() {
    SortedSet<String> set = new SafeTreeSet<>();
    set.add("e");
    SortedSet<String> copy = SerializableTester.reserializeAndAssert(set);
    assertEquals(set.comparator(), copy.comparator());
  }

  @GwtIncompatible // SerializableTester

    return tmp.toArray(new String[0]);
  }

  static <T> Comparator<T> arbitraryNullFriendlyComparator() {
    return new NullFriendlyComparator<>();
  }

  private static final class NullFriendlyComparator<T> implements Comparator<T>, Serializable {
    @Override
    public int compare(T left, T right) {
      return String.valueOf(left).compareTo(String.valueOf(right));
    }
  }

    }

    @Override
    public Iterator<E> iterator() {
      return Multisets.elementIterator(multiset().entrySet().iterator());
    }

    @Override
    public Comparator<? super E> comparator() {
      return multiset().comparator();
    }

    @Override
    public SortedSet<E> subSet(@ParametricNullness E fromElement, @ParametricNullness E toElement) {

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.lifecycle.internal.concurrent;

import javax.inject.Named;

import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.function.Consumer;
import java.util.stream.Collectors;

      implements Supplier<SortedSet<V>>, Serializable {
    private final Comparator<? super V> comparator;

    TreeSetSupplier(Comparator<? super V> comparator) {
      this.comparator = checkNotNull(comparator);
    }

    @Override
    public SortedSet<V> get() {
      return new TreeSet<>(comparator);
    }
  }

  private static final class EnumSetSupplier<V extends Enum<V>>

     * @param comparator the comparator for ordering the elements in the priority queue
     * @return a new instance of {@link PriorityBlockingQueue}
     * @see PriorityBlockingQueue#PriorityBlockingQueue(int, Comparator)
     */
    public static <E> PriorityBlockingQueue<E> newPriorityBlockingQueue(final int initialCapacity, final Comparator<? super E> comparator) {

 * invoke methods, they invoke methods on the {@code ForwardingSortedSet}.
 *
 * <p>Each of the {@code standard} methods, where appropriate, uses the set's comparator (or the
 * natural ordering of the elements, if there is no comparator) to test element equality. As a
 * result, if the comparator is not consistent with equals, some of the standard implementations may
 * violate the {@code Set} contract.
 *

    final E lastInclusive;
    private final Comparator<? super E> comparator;
    private final TestSortedSetGenerator<E> delegate;

    public SortedSetSubsetTestSetGenerator(
        TestSortedSetGenerator<E> delegate, Bound to, Bound from) {
      this.to = to;
      this.from = from;
      this.delegate = delegate;

      SortedSet<E> emptySet = delegate.create();
      this.comparator = emptySet.comparator();

          Comparator<? super E> comparator = spliterator.getComparator();
          if (comparator == null) {
            // A sorted spliterator with no comparator is already using natural order.
            // (We could probably find a way to avoid rawtypes here if we wanted.)
            @SuppressWarnings({"unchecked", "rawtypes"})
            Comparator<? super E> naturalOrder =

          Comparator<? super E> comparator = spliterator.getComparator();
          if (comparator == null) {
            // A sorted spliterator with no comparator is already using natural order.
            // (We could probably find a way to avoid rawtypes here if we wanted.)
            @SuppressWarnings({"unchecked", "rawtypes"})
            Comparator<? super E> naturalOrder =