* #elementSet()}. Override those methods for better performance.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class AbstractSortedMultiset<E extends @Nullable Object> extends AbstractMultiset<E>
    implements SortedMultiset<E> {
  private final Comparator<? super E> comparator;

  // needed for serialization
  @SuppressWarnings("unchecked")
  AbstractSortedMultiset() {

    multiset.add("a");
    assertThrows(UnsupportedOperationException.class, () -> multiset.remove("a"));
    assertTrue(multiset.contains("a"));
  }

  private static class NoRemoveMultiset<E extends @Nullable Object> extends AbstractMultiset<E>
      implements Serializable {
    final Map<E, Integer> backingMap = new HashMap<>();

    @Override
    public int size() {
      return Multisets.linearTimeSizeImpl(this);

 * methods that they depend on are thread-safe.
 *
 * @author Mike Bostock
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingMapEntry<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingObject implements Map.Entry<K, V> {
  // TODO(lowasser): identify places where thread safety is actually lost

  /** Constructor for use by subclasses. */

@GwtCompatible
@NullMarked
public abstract class IteratorTester<E extends @Nullable Object>
    extends AbstractIteratorTester<E, Iterator<E>> {
  /**
   * Creates an IteratorTester.
   *
   * @param steps how many operations to test for each tested pair of iterators
   * @param features the features supported by the iterator
   */
  protected IteratorTester(
      int steps,
      Iterable<? extends IteratorFeature> features,

 * not its subclasses) can be reused when copied from one ImmutableMap to another.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible // unnecessary
class ImmutableMapEntry<K, V> extends SimpleImmutableEntry<K, V> {
  /**
   * Creates an {@code ImmutableMapEntry} array to hold parameterized entries. The result must never
   * be upcast back to ImmutableMapEntry[] (or Object[], etc.), or allowed to escape the class.

import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.cli.Options;

/**
 * Defines the options specific to Maven operations.
 * This interface extends the general {@link Options} interface, adding Maven-specific configuration options.
 *
 * <p>These options represent the various flags and settings available through the Maven CLI,

    }

    interface PhasePointer extends Pointer {
        /**
         * Returns the type of pointer, which is always PROJECT for a PhasePointer.
         *
         * @return the PROJECT pointer type
         */
        @Override
        default Type type() {
            return Type.PROJECT;
        }
    }

    interface DependenciesPointer extends Pointer {
        /**

 *
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class AbstractSortedKeySortedSetMultimap<
        K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractSortedSetMultimap<K, V> {

  AbstractSortedKeySortedSetMultimap(SortedMap<K, Collection<V>> map) {
    super(map);
  }

  @Override
  public SortedMap<K, Collection<V>> asMap() {

 */
@GwtCompatible
final class AllEqualOrdering extends Ordering<@Nullable Object> implements Serializable {
  static final AllEqualOrdering INSTANCE = new AllEqualOrdering();

  @Override
  @SuppressWarnings("UnusedVariable") // intentionally weird Comparator
  public int compare(@Nullable Object left, @Nullable Object right) {
    return 0;
  }

  @Override
  public <E extends @Nullable Object> List<E> sortedCopy(Iterable<E> iterable) {

      // There is no StackOverflowError under GWT/J2CL.
      throw (Error) t;
    }
  }

  static <V extends @Nullable Object> V get(AbstractFuture<V> future)
      throws InterruptedException, ExecutionException {
    return future.getFromAlreadyDoneTrustedFuture();
  }

  static <V extends @Nullable Object> V get(AbstractFuture<V> future, long timeout, TimeUnit unit)