static final int SPLITERATOR_CHARACTERISTICS =
      Spliterator.IMMUTABLE | Spliterator.NONNULL | Spliterator.ORDERED;

  ImmutableCollection() {}

  public abstract UnmodifiableIterator<E> iterator();

  public boolean contains(@Nullable Object object) {
    return object != null && super.contains(object);
  }

  public final boolean add(E e) {
    throw new UnsupportedOperationException();

  ImmutableCollection() {}

  /** Returns an unmodifiable iterator across the elements in this collection. */
  @Override
  public abstract UnmodifiableIterator<E> iterator();

  @Override
  public Spliterator<E> spliterator() {
    return Spliterators.spliterator(this, SPLITERATOR_CHARACTERISTICS);
  }

  private static final Object[] EMPTY_ARRAY = {};

  ImmutableCollection() {}

  /** Returns an unmodifiable iterator across the elements in this collection. */
  @Override
  public abstract UnmodifiableIterator<E> iterator();

  @Override
  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
  @IgnoreJRERequirement // used only from APIs with Java 8 types in them