@SuppressWarnings("unchecked") // TODO(cpovirk): Consider storing Entry<?, ?>[] instead.
  static final RegularImmutableBiMap<Object, Object> EMPTY =
      new RegularImmutableBiMap<>(
          null, null, (Entry<Object, Object>[]) ImmutableMap.EMPTY_ENTRY_ARRAY, 0, 0);

  static final double MAX_LOAD_FACTOR = 1.2;

  private final transient @Nullable ImmutableMapEntry<K, V> @Nullable [] keyTable;

   * @param sig The method signature
   */
  @GwtIncompatible // ArbitraryInstances
  @J2ktIncompatible
  private Object[] getParametersForSignature(
      @Nullable Object firstParam, ImmutableList<Class<?>> sig) {
    Object[] params = new Object[sig.size()];
    params[0] = firstParam;
    if (params.length > 1) {
      params[1] = "";
      if (params.length > 2) {

   * @param sig The method signature
   */
  @GwtIncompatible // ArbitraryInstances
  @J2ktIncompatible
  private Object[] getParametersForSignature(
      @Nullable Object firstParam, ImmutableList<Class<?>> sig) {
    Object[] params = new Object[sig.size()];
    params[0] = firstParam;
    if (params.length > 1) {
      params[1] = "";
      if (params.length > 2) {

    @Override
    public boolean containsKey(Object key) {
      return standardContainsKey(key);
    }

    @Override
    public boolean containsValue(Object value) {
      return standardContainsValue(value);
    }

    @Override
    public void putAll(Map<? extends K, ? extends V> map) {
      standardPutAll(map);
    }

    @Override
    public @Nullable V remove(Object object) {
      return standardRemove(object);

    @Override
    public Collection<V> create(Object... elements) {
      K k =
          ((TestMultimapGenerator<K, V, M>) multimapGenerator.getInnerGenerator())
              .sampleKeys()
              .e0();
      Object[] entries = new Object[elements.length];
      for (int i = 0; i < elements.length; i++) {
        @SuppressWarnings("unchecked") // These come from Entry<K, V> objects somewhere.
        V value = (V) elements[i];

    if (comparator != null) {
      return comparator;
    }
    return NATURAL_ORDER;
  }

  @Override
  public boolean contains(Object object) {
    return delegate.contains(checkValid(object));
  }

  @Override
  public boolean containsAll(Collection<?> c) {
    return delegate.containsAll(c);
  }

  @Override
  public Iterator<E> descendingIterator() {

  private enum NullEntry implements ReferenceEntry<Object, Object> {
    INSTANCE;

    @Override
    public @Nullable ValueReference<Object, Object> getValueReference() {
      return null;
    }

    @Override
    public void setValueReference(ValueReference<Object, Object> valueReference) {}

    @Override
    public @Nullable ReferenceEntry<Object, Object> getNext() {
      return null;
    }

  }

  /** Returns a {@link ValueGraphBuilder} for building directed graphs. */
  public static ValueGraphBuilder<Object, Object> directed() {
    return new ValueGraphBuilder<>(true);
  }

  /** Returns a {@link ValueGraphBuilder} for building undirected graphs. */
  public static ValueGraphBuilder<Object, Object> undirected() {
    return new ValueGraphBuilder<>(false);
  }

  /**

  }

  public void testConstant() {
    Function<@Nullable Object, Object> f = Functions.<Object>constant("correct");
    assertEquals("correct", f.apply(new Object()));
    assertEquals("correct", f.apply(null));

    Function<@Nullable Object, @Nullable String> g = Functions.constant(null);
    assertThat(g.apply(2)).isNull();
    assertThat(g.apply(null)).isNull();

    // exercise some classes from the parallel ClassLoader.
    AtomicReference<Object> sepFrqA =
        new AtomicReference<Object>(sepFrqC.getDeclaredConstructor().newInstance());
    Class<?> sepFwrC = sepLoader.loadClass(MyFinalizableWeakReference.class.getName());
    Constructor<?> sepFwrCons = sepFwrC.getConstructor(Object.class, sepFrqC);