@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@NullMarked
public abstract class AbstractMultimapTester<
        K extends @Nullable Object, V extends @Nullable Object, M extends Multimap<K, V>>
    extends AbstractContainerTester<M, Entry<K, V>> {

  private M multimap;

  protected M multimap() {
    return multimap;
  }

  /**

public class FeatureSpecificTestSuiteBuilderTest extends TestCase {
  private static final class MyTestSuiteBuilder
      extends FeatureSpecificTestSuiteBuilder<MyTestSuiteBuilder, String> {
    @SuppressWarnings("rawtypes") // class literals
    @Override
    protected List<Class<? extends AbstractTester>> getTesters() {
      return Collections.<Class<? extends AbstractTester>>singletonList(MyTester.class);
    }
  }

 * A skeleton implementation of a descending multiset. Only needs {@code forwardMultiset()} and
 * {@code entryIterator()}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class DescendingMultiset<E extends @Nullable Object> extends ForwardingMultiset<E>
    implements SortedMultiset<E> {
  abstract SortedMultiset<E> forwardMultiset();

  @LazyInit private transient @Nullable Comparator<? super E> comparator;

  @Override

  }

  private static <K, V> Map<K, V> newHashMap(
      Collection<? extends Entry<? extends K, ? extends V>> entries) {
    HashMap<K, V> map = new HashMap<>();
    for (Entry<? extends K, ? extends V> entry : entries) {
      map.put(entry.getKey(), entry.getValue());
    }
    return map;
  }

  // public named classes with a public default constructor.

  public static final class DoublesAsListGenerator extends TestDoubleListGenerator {
    @Override
    protected List<Double> create(Double[] elements) {
      return asList(elements);
    }
  }

  public static final class DoublesAsListHeadSubListGenerator extends TestDoubleListGenerator {
    @Override
    protected List<Double> create(Double[] elements) {

/**
 * An Iterator implementation which draws elements from a queue, removing them from the queue as it
 * iterates. This class is not thread safe.
 */
@GwtCompatible
final class ConsumingQueueIterator<T extends @Nullable Object> extends AbstractIterator<T> {
  private final Queue<T> queue;

  ConsumingQueueIterator(Queue<T> queue) {
    this.queue = checkNotNull(queue);
  }

  @Override
  protected @Nullable T computeNext() {

    result.usingGenerator(generator);
    return result;
  }

  @SuppressWarnings("rawtypes") // class literals
  @Override
  protected List<Class<? extends AbstractTester>> getTesters() {
    List<Class<? extends AbstractTester>> testers = copyToList(super.getTesters());
    testers.add(SetMultimapAsMapTester.class);
    testers.add(SetMultimapEqualsTester.class);
    testers.add(SetMultimapPutTester.class);

    return new CacheLoader<K, V>() {
      @Override
      public V load(K key) throws Exception {
        return loader.load(key);
      }

      @Override
      public Map<K, V> loadAll(Iterable<? extends K> keys) throws Exception {
        Map<K, V> result = new HashMap<>(); // allow nulls
        for (K key : keys) {
          result.put(key, load(key));
        }
        return result;
      }
    };
  }

 * "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

 * #elementSet()}. Override those methods for better performance.
 *
 * @author Kevin Bourrillion
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class AbstractMultiset<E extends @Nullable Object> extends AbstractCollection<E>
    implements Multiset<E> {
  // Query Operations

  @Override
  public boolean isEmpty() {
    return entrySet().isEmpty();
  }

  @Override