* @throws IndexOutOfBoundsException if either index is negative or is greater than {@code size},
   *     or if {@code end} is less than {@code start}
   * @throws IllegalArgumentException if {@code size} is negative
   */
  public static void checkPositionIndexes(int start, int end, int size) {
    // Carefully optimized for execution by hotspot (explanatory comment above)
    if (start < 0 || end < start || end > size) {

 * Comparator} or {@link Comparable} type whose comparison behavior is <i>inconsistent with
 * equals</i>. That is, {@code a.compareTo(b)} or {@code comparator.compare(a, b)} should equal zero
 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting map will
 * not correctly obey its specification.
 *
 * <p>See the Guava User Guide article on <a href=

                    // Remove last element, if size > 1
                    Set<String> set1 =
                        (size > 1)
                            ? Sets.newHashSet(Arrays.asList(elements).subList(0, size - 1))
                            : Sets.newHashSet(elements);
                    // Remove first element, if size > 0
                    Set<String> set2 =
                        (size > 0)

      public boolean hasNext() {
        checkConcurrentModification();
        return index < elements.size();
      }

      @Override
      public E next() {
        checkConcurrentModification();
        if (!hasNext()) {
          throw new NoSuchElementException();
        }
        canRemove = true;
        return elements.get(index++);
      }

      @Override
      public void remove() {

      Waiter pred = null;
      Waiter curr = waiters;
      if (curr == Waiter.TOMBSTONE) {
        return; // give up if someone is calling complete
      }
      Waiter succ;
      while (curr != null) {
        succ = curr.next;
        if (curr.thread != null) { // we aren't unlinking this node, update pred.
          pred = curr;
        } else if (pred != null) { // We are unlinking this node and it has a predecessor.

 * Comparator} or {@link Comparable} type whose comparison behavior is <i>inconsistent with
 * equals</i>. That is, {@code a.compareTo(b)} or {@code comparator.compare(a, b)} should equal zero
 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting map will
 * not correctly obey its specification.
 *
 * <p>See the Guava User Guide article on <a href=

      Collection<E> collection, @CheckForNull Object mutex) {
    if (collection instanceof SortedSet) {
      return sortedSet((SortedSet<E>) collection, mutex);
    }
    if (collection instanceof Set) {
      return set((Set<E>) collection, mutex);
    }
    if (collection instanceof List) {
      return list((List<E>) collection, mutex);
    }

      if (count != 0) { // read-volatile
        for (E e = getFirst(hash); e != null; e = e.getNext()) {
          if (e.getHash() != hash) {
            continue;
          }

          K entryKey = e.getKey();
          if (entryKey == null) {
            tryDrainReferenceQueues();
            continue;
          }

          if (map.keyEquivalence.equivalent(key, entryKey)) {

  public static <E extends Enum<E>> ImmutableSet<E> immutableEnumSet(Iterable<E> elements) {
    if (elements instanceof ImmutableEnumSet) {
      return (ImmutableEnumSet<E>) elements;
    } else if (elements instanceof Collection) {
      Collection<E> collection = (Collection<E>) elements;
      if (collection.isEmpty()) {
        return ImmutableSet.of();
      } else {

   *     or {@code -1} if no character matches
   * @throws IndexOutOfBoundsException if start is negative or greater than {@code
   *     sequence.length()}
   */
  public int indexIn(CharSequence sequence, int start) {
    int length = sequence.length();
    checkPositionIndex(start, length);
    for (int i = start; i < length; i++) {
      if (matches(sequence.charAt(i))) {
        return i;