* the map directly affect the cache.
   *
   * <p>Iterators from the returned map are at least <i>weakly consistent</i>: they are safe for
   * concurrent use, but if the cache is modified (including by eviction) after the iterator is
   * created, it is undefined which of the changes (if any) will be reflected in that iterator.
   *

    return new Iterable<T>() {
      @Override
      public Iterator<T> iterator() {
        return new AbstractIterator<T>() {
          private final Iterator<? extends Optional<? extends T>> iterator =
              checkNotNull(optionals.iterator());

          @Override
          @CheckForNull
          protected T computeNext() {
            while (iterator.hasNext()) {

  }

  @Override
  Iterator<Entry<E>> entryIterator() {
    // AbstractIterator makes this fairly clean, but it doesn't support remove(). To support
    // remove(), we create an AbstractIterator, and then use ForwardingIterator to delegate to it.
    Iterator<Entry<E>> readOnlyIterator =
        new AbstractIterator<Entry<E>>() {
          private final Iterator<Map.Entry<E, AtomicInteger>> mapEntries =

    Iterator<String> iterator = skip(list, 2).iterator();
    assertThrows(IllegalStateException.class, () -> iterator.remove());
  }

  public void testSkip_allOfImmutableList_modifiable() {
    List<String> list = ImmutableList.of("a", "b");
    Iterator<String> iterator = skip(list, 2).iterator();
    assertThrows(UnsupportedOperationException.class, () -> iterator.remove());
  }

    return indexBeforeRemove - 1;
  }

  @Override
  public Iterator<E> iterator() {
    Set<E> delegate = delegateOrNull();
    if (delegate != null) {
      return delegate.iterator();
    }
    return new Iterator<E>() {
      int expectedMetadata = metadata;
      int currentIndex = firstEntryIndex();
      int indexToRemove = -1;

      lastEntry = entry;
    }

    @Override
    public void setSuccessorInValueSet(ValueSetLink<K, V> entry) {
      firstEntry = entry;
    }

    @Override
    public Iterator<V> iterator() {
      return new Iterator<V>() {
        ValueSetLink<K, V> nextEntry = firstEntry;
        @CheckForNull ValueEntry<K, V> toRemove;
        int expectedModCount = modCount;

        private void checkForComodification() {

      iterator.remove();
    }
  }

  /** ValueIterator build on top of EntryIterator. */
  final class ValueIterator implements Iterator<V> {
    private EntryIterator iterator;

    ValueIterator() {
      iterator = new EntryIterator();
    }

    @Override
    public boolean hasNext() {
      return iterator.hasNext();
    }

    @Override
    public V next() {

   * of the deque's iterators:
   *
   * <pre>{@code
   * Deque<E> deque = Queues.synchronizedDeque(Queues.<E>newArrayDeque());
   * ...
   * deque.add(element);  // Needn't be in synchronized block
   * ...
   * synchronized (deque) {  // Must synchronize on deque!
   *   Iterator<E> i = deque.iterator(); // Must be in synchronized block
   *   while (i.hasNext()) {

  /** @since 12.0 */
  @GwtIncompatible // NavigableSet
  @Override
  @CheckForNull
  public E lower(E e) {
    return Iterators.<@Nullable E>getNext(headSet(e, false).descendingIterator(), null);
  }

  /** @since 12.0 */
  @Override
  @CheckForNull
  public E floor(E e) {
    return Iterators.<@Nullable E>getNext(headSet(e, true).descendingIterator(), null);
  }

  /** @since 12.0 */
  @Override

   * of the deque's iterators:
   *
   * <pre>{@code
   * Deque<E> deque = Queues.synchronizedDeque(Queues.<E>newArrayDeque());
   * ...
   * deque.add(element);  // Needn't be in synchronized block
   * ...
   * synchronized (deque) {  // Must synchronize on deque!
   *   Iterator<E> i = deque.iterator(); // Must be in synchronized block
   *   while (i.hasNext()) {