* atomic unless otherwise noted.
 *
 * <p>Instances of this class are serializable if the keys are serializable.
 *
 * <p><b>Note:</b> If your values are always positive and less than 2^31, you may wish to use a
 * {@link com.google.common.collect.Multiset} such as {@link
 * com.google.common.collect.ConcurrentHashMultiset} instead.
 *

    public EntryComparator(@Nullable Comparator<? super K> keyComparator) {
      this.keyComparator = keyComparator;
    }

    @Override
    @SuppressWarnings("unchecked") // no less safe than putting it in the map!
    public int compare(Entry<K, V> a, Entry<K, V> b) {
      return (keyComparator == null)
          ? ((Comparable) a.getKey()).compareTo(b.getKey())

    int skipped = advance(iterator, position);
    if (!iterator.hasNext()) {
      throw new IndexOutOfBoundsException(
          "position ("
              + position
              + ") must be less than the number of elements that remained ("
              + skipped
              + ")");
    }
    return iterator.next();
  }

  /**