* "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap}</a>.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible
public interface BiMap<K extends @Nullable Object, V extends @Nullable Object> extends Map<K, V> {
  // Modification Operations

  /**
   * {@inheritDoc}
   *
   * @throws IllegalArgumentException if the given value is already bound to a different key in this

import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import java.util.Comparator;
import org.jspecify.annotations.Nullable;

/** An ordering for a pre-existing comparator. */
@GwtCompatible
final class ComparatorOrdering<T extends @Nullable Object> extends Ordering<T>
    implements Serializable {
  final Comparator<T> comparator;

  ComparatorOrdering(Comparator<T> comparator) {

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import java.util.Collection;
import org.jspecify.annotations.Nullable;

/**
 * A GWT-only class only used by GWT emulations. It is used to consolidate the definitions of method
 * delegation to save code size.
 *
 * @author Hayward Chan
 */

  }

  /**
   * Class for testing all permutations of nullable/non-nullable two-argument methods using
   * testMethod().
   *
   * <ul>
   *   <li>normalNormal: two params, neither is Nullable
   *   <li>nullableNormal: only first param is Nullable
   *   <li>normalNullable: only second param is Nullable
   *   <li>nullableNullable: both params are Nullable
   * </ul>
   */
  public static class TwoArg {

  @VisibleForTesting
  static final class ValueEntry<K extends @Nullable Object, V extends @Nullable Object>
      extends SimpleImmutableEntry<K, V> {
    final int smearedValueHash;

    @Nullable ValueEntry<K, V> nextInValueBucket;

    private @Nullable ValueEntry<K, V> predecessorInValueSet;
    private @Nullable ValueEntry<K, V> successorInValueSet;

    private @Nullable ValueEntry<K, V> predecessorInMultimap;

@GwtIncompatible
public abstract class ForwardingNavigableMap<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingSortedMap<K, V> implements NavigableMap<K, V> {

  /** Constructor for use by subclasses. */
  protected ForwardingNavigableMap() {}

  @Override
  protected abstract NavigableMap<K, V> delegate();

  @Override
  public @Nullable Entry<K, V> lowerEntry(@ParametricNullness K key) {

@GwtIncompatible
public abstract class ForwardingNavigableMap<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingSortedMap<K, V> implements NavigableMap<K, V> {

  /** Constructor for use by subclasses. */
  protected ForwardingNavigableMap() {}

  @Override
  protected abstract NavigableMap<K, V> delegate();

  @Override
  public @Nullable Entry<K, V> lowerEntry(@ParametricNullness K key) {

    }
  }

  private static <E extends @Nullable Object> E getElementOrThrow(@Nullable Entry<E> entry) {
    if (entry == null) {
      throw new NoSuchElementException();
    }
    return entry.getElement();
  }

  private static <E extends @Nullable Object> @Nullable E getElementOrNull(
      @Nullable Entry<E> entry) {
    return (entry == null) ? null : entry.getElement();
  }

 *
 * @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() {

      // 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)