/** Support for {@link Iterator#remove()}. */
  SUPPORTS_REMOVE,
  /**
   * Support for {@link ListIterator#add(Object)}; ignored for plain {@link Iterator}
   * implementations.
   */
  SUPPORTS_ADD,
  /**
   * Support for {@link ListIterator#set(Object)}; ignored for plain {@link Iterator}
   * implementations.
   */
  SUPPORTS_SET;

  /**

  /** Support for {@link Iterator#remove()}. */
  SUPPORTS_REMOVE,
  /**
   * Support for {@link ListIterator#add(Object)}; ignored for plain {@link Iterator}
   * implementations.
   */
  SUPPORTS_ADD,
  /**
   * Support for {@link ListIterator#set(Object)}; ignored for plain {@link Iterator}
   * implementations.
   */
  SUPPORTS_SET;

  /**

      return oldValue;
    }
  }

  Iterator<Entry<K, V>> entrySetIterator() {
    final Iterator<Entry<K, V>> iterator = delegate.entrySet().iterator();
    return new Iterator<Entry<K, V>>() {
      @CheckForNull Entry<K, V> entry;

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

      @Override
      public Entry<K, V> next() {

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Iterator;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An iterator which forwards all its method calls to another iterator. Subclasses should override
 * one or more methods to modify the behavior of the backing iterator as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

        this.list = list;
        this.mapper = mapper;
    }

    @Override
    public Iterator<U> iterator() {
        Iterator<V> it = list.iterator();
        return new Iterator<U>() {
            @Override
            public boolean hasNext() {
                return it.hasNext();
            }

            @Override
            public U next() {

  }

  public static <E extends Enum<E>> EnumMultiset<E> create(Iterable<E> elements) {
    Iterator<E> iterator = elements.iterator();
    checkArgument(iterator.hasNext(), "EnumMultiset constructor passed empty Iterable");
    EnumMap<E, Count> map = new EnumMap<>(getDeclaringClassOrObjectForJ2cl(iterator.next()));
    EnumMultiset<E> multiset = new EnumMultiset<>(map);
    Iterables.addAll(multiset, elements);

    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      StringBuilder sb = new StringBuilder();
      Iterator<String> iterator = components.iterator();
      if (iterator.hasNext()) {
        sb.append(iterator.next().toString());
        while (iterator.hasNext()) {
          sb.append(DELIMITER_STRING);
          sb.append(iterator.next());
        }
      }
      dummy ^= sb.toString().length();
    }
    return dummy;
  }

  public void testFreesNextReference() {
    Iterator<Object> itr =
        new AbstractIterator<Object>() {
          @Override
          public Object computeNext() {
            return new Object();
          }
        };
    WeakReference<Object> ref = new WeakReference<>(itr.next());
    GcFinalization.awaitClear(ref);
  }

  public void testReentrantHasNext() {
    Iterator<Integer> iter =

  public void testFreesNextReference() {
    Iterator<Object> itr =
        new AbstractIterator<Object>() {
          @Override
          public Object computeNext() {
            return new Object();
          }
        };
    WeakReference<Object> ref = new WeakReference<>(itr.next());
    GcFinalization.awaitClear(ref);
  }

  public void testReentrantHasNext() {
    Iterator<Integer> iter =

  @CollectionSize.Require(SEVERAL)
  public void testClearConcurrentWithIteration() {
    try {
      Iterator<E> iterator = collection.iterator();
      collection.clear();
      iterator.next();
      /*
       * We prefer for iterators to fail immediately on hasNext, but ArrayList
       * and LinkedList will notably return true on hasNext here!
       */