private static class UnmodifiableMultimap<K extends @Nullable Object, V extends @Nullable Object>
      extends ForwardingMultimap<K, V> implements Serializable {
    final Multimap<K, V> delegate;
    @LazyInit transient @Nullable Collection<Entry<K, V>> entries;
    @LazyInit transient @Nullable Multiset<K> keys;
    @LazyInit transient @Nullable Set<K> keySet;
    @LazyInit transient @Nullable Collection<V> values;

    return (Collector) TO_OPTIONAL;
  }

  private static final Object NULL_PLACEHOLDER = new Object();

  private static final Collector<@Nullable Object, ?, @Nullable Object> ONLY_ELEMENT =
      Collector.<@Nullable Object, ToOptionalState, @Nullable Object>of(
          ToOptionalState::new,
          (state, o) -> state.add((o == null) ? NULL_PLACEHOLDER : o),
          ToOptionalState::combine,
          state -> {

  public void assertEqualHashCode(
      Predicate<? super @Nullable Integer> expected, Predicate<? super @Nullable Integer> actual) {
    assertEquals(actual + " should hash like " + expected, expected.hashCode(), actual.hashCode());
  }

  public void testHashCodeForBooleanOperations() {
    Predicate<@Nullable Integer> p1 = Predicates.isNull();
    Predicate<@Nullable Integer> p2 = isOdd();

  @Generates
  static <K, V> Map<K, V> generateMap(@Nullable K key, @Nullable V value) {
    return generateHashdMap(key, value);
  }

  @Generates
  static <K, V> HashMap<K, V> generateHashdMap(@Nullable K key, @Nullable V value) {
    return generateLinkedHashMap(key, value);
  }

  @Generates
  static <K, V> LinkedHashMap<K, V> generateLinkedHashMap(@Nullable K key, @Nullable V value) {

    Callable<@Nullable Void> cancelRunnable =
        new Callable<@Nullable Void>() {
          @Override
          public @Nullable Void call() {
            cancellationSuccess.set(currentFuture.get().cancel(true));
            awaitUnchecked(barrier);
            return null;
          }
        };
    Callable<@Nullable Void> setFutureCompleteSuccessfullyRunnable =

     * @param defaultReply the default reply value
     * @return the string entered by the user
     * @throws PrompterException if an exception occurs
     */
    @Nonnull
    String prompt(@Nullable String message, @Nullable List<String> possibleValues, @Nullable String defaultReply)
            throws PrompterException;

    /**
     * Prompts the user for a password.
     *
     * @param message the message to display

   */
  static <T extends @Nullable Object> T[] toArrayImpl(
      @Nullable Object[] src, int offset, int len, T[] dst) {
    checkPositionIndexes(offset, offset + len, src.length);
    if (dst.length < len) {
      dst = newArray(dst, len);
    } else if (dst.length > len) {
      @Nullable Object[] unsoundlyCovariantArray = dst;
      unsoundlyCovariantArray[len] = null;
    }

    public @Nullable K floorKey(K key) {
      return standardFloorKey(key);
    }

    @Override
    public @Nullable Entry<K, V> ceilingEntry(K key) {
      return standardCeilingEntry(key);
    }

    @Override
    public @Nullable K ceilingKey(K key) {
      return standardCeilingKey(key);
    }

    @Override
    public @Nullable Entry<K, V> higherEntry(K key) {
      return standardHigherEntry(key);

   * @throws IllegalArgumentException if {@code size} is nonpositive
   */
  public static <T extends @Nullable Object>
      UnmodifiableIterator<List<@Nullable T>> paddedPartition(Iterator<T> iterator, int size) {
    return partitionImpl(iterator, size, true);
  }

  private static <T extends @Nullable Object> UnmodifiableIterator<List<@Nullable T>> partitionImpl(
      Iterator<T> iterator, int size, boolean pad) {
    checkNotNull(iterator);

  private CacheBuilder<Object, Object> createCacheBuilder(
      @Nullable Integer concurrencyLevel,
      @Nullable Integer initialCapacity,
      @Nullable Integer maximumSize,
      @Nullable DurationSpec expireAfterWrite,
      @Nullable DurationSpec expireAfterAccess,
      @Nullable DurationSpec refresh,
      @Nullable Strength keyStrength,
      @Nullable Strength valueStrength) {