@ElementTypesAreNonnullByDefault
public abstract class AbstractListeningExecutorService extends AbstractExecutorService
    implements ListeningExecutorService {

  /**
   * @since 19.0 (present with return type {@code ListenableFutureTask} since 14.0)
   */
  @CanIgnoreReturnValue // TODO(kak): consider removing this
  @Override
  protected final <T extends @Nullable Object> RunnableFuture<T> newTaskFor(

/** An ordering that treats {@code null} as less than all other values. */
@GwtCompatible(serializable = true)
@ElementTypesAreNonnullByDefault
final class NullsFirstOrdering<T extends @Nullable Object> extends Ordering<@Nullable T>
    implements Serializable {
  final Ordering<? super T> ordering;

  NullsFirstOrdering(Ordering<? super T> ordering) {
    this.ordering = ordering;
  }

  @Override

   *
   * <p>The type specification is {@code <E extends Comparable>}, instead of the more specific
   * {@code <E extends Comparable<? super E>>}, to support classes defined without generics.
   */
  @SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
  public static <E extends Comparable> TreeMultiset<E> create(Iterable<? extends E> elements) {
    TreeMultiset<E> multiset = create();

     * @since 19.0
     */
    @CanIgnoreReturnValue
    public Builder<K, V> putAll(Iterable<? extends Entry<? extends K, ? extends V>> entries) {
      if (entries instanceof Collection) {
        ensureCapacity(size + ((Collection<?>) entries).size());
      }
      for (Entry<? extends K, ? extends V> entry : entries) {
        put(entry);
      }
      return this;
    }

    /**

   */
  public <E1 extends E> NetworkBuilder<N, E1> edgeOrder(ElementOrder<E1> edgeOrder) {
    NetworkBuilder<N, E1> newBuilder = cast();
    newBuilder.edgeOrder = checkNotNull(edgeOrder);
    return newBuilder;
  }

  /** Returns an empty {@link MutableNetwork} with the properties of this {@link NetworkBuilder}. */
  public <N1 extends N, E1 extends E> MutableNetwork<N1, E1> build() {

    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 = Maps.newHashMap();

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

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@ElementTypesAreNonnullByDefault
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;
  }

  /**

        final V value = parent.remove(key);
        if (value != null) {
            return value;
        }
        return parent.remove(key);
    }

    @Override
    public void putAll(final Map<? extends K, ? extends V> m) {
        parent.putAll(m);
    }

    @Override
    public void clear() {
        parent.clear();
    }

    @Override
    public Set<K> keySet() {

    // used under GWT, etc., since the override of this method does not exist there
    ImmutableMap<Class<? extends Throwable>, Predicate<Throwable>> exceptions() {
      return ImmutableMap.of();
    }
  }

  private static final ImmutableMap<Class<? extends Throwable>, Predicate<Throwable>> INSTANCE_OF =
      ImmutableMap.<Class<? extends Throwable>, Predicate<Throwable>>builder()

  @J2ktIncompatible
  @GwtIncompatible // PriorityBlockingQueue
  public static <E extends Comparable> PriorityBlockingQueue<E> newPriorityBlockingQueue(
      Iterable<? extends E> elements) {
    if (elements instanceof Collection) {
      return new PriorityBlockingQueue<>((Collection<? extends E>) elements);
    }
    PriorityBlockingQueue<E> queue = new PriorityBlockingQueue<>();