@Override
  public Character[] createArray(int length) {
    return new Character[length];
  }

  /** Returns the original element list, unchanged. */
  @Override
  public List<Character> order(List<Character> insertionOrder) {
    return insertionOrder;
  }

  @Override
  public UnhashableObject[] createArray(int length) {
    return new UnhashableObject[length];
  }

  @Override
  public Iterable<UnhashableObject> order(List<UnhashableObject> insertionOrder) {
    return insertionOrder;
  }

  @Override
  public Character[] createArray(int length) {
    return new Character[length];
  }

  /** Returns the original element list, unchanged. */
  @Override
  public List<Character> order(List<Character> insertionOrder) {
    return insertionOrder;
  }

  @Override
  public AnEnum[] createArray(int length) {
    return new AnEnum[length];
  }

  /** Sorts the enums according to their natural ordering. */
  @Override
  public List<AnEnum> order(List<AnEnum> insertionOrder) {
    sort(insertionOrder);
    return insertionOrder;
  }

 * average, in the marking phase, not {@code 5.0} as in {@code java.util.HashSet}.
 *
 * <p>If there are no removals, then {@link #iterator iteration} order is the same as insertion
 * order. Any removal invalidates any ordering guarantees.
 *
 * <p>This class should not be assumed to be universally superior to {@code java.util.HashSet}.

 *
 * <p>This class serializes execution of <i>submitted</i> tasks but not any <i>listeners</i> of
 * those tasks.
 *
 * <p>Submitted tasks have a happens-before order as defined in the Java Language Specification.
 * Tasks execute with the same happens-before order that the function calls to {@link #submit} and
 * {@link #submitAsync} that submitted those tasks had.
 *

  }

  /**
   * Returns an immutable map instance containing the given entries. Internally, the returned map
   * will be backed by an {@link EnumMap}.
   *
   * <p>The iteration order of the returned map follows the enum's iteration order, not the order in
   * which the elements appear in the given map.
   *
   * @param map the map to make an immutable copy of
   * @return an immutable map containing those entries
   * @since 14.0

  }

  /**
   * Returns an immutable map instance containing the given entries. Internally, the returned map
   * will be backed by an {@link EnumMap}.
   *
   * <p>The iteration order of the returned map follows the enum's iteration order, not the order in
   * which the elements appear in the given map.
   *
   * @param map the map to make an immutable copy of
   * @return an immutable map containing those entries
   * @since 14.0

   * elements.
   *
   * <p>If the mapped keys contain duplicates (according to the comparator), the values are merged
   * using the specified merging function. Entries will appear in the encounter order of the first
   * occurrence of the key.
   *
   * @since 21.0
   */
  public static <T extends @Nullable Object, K, V>
      Collector<T, ?, ImmutableSortedMap<K, V>> toImmutableSortedMap(

   *     {@code double}) in the proper order.
   */
  private void writeObject(ObjectOutputStream s) throws IOException {
    s.defaultWriteObject();

    // Write out array length
    int length = length();
    s.writeInt(length);

    // Write out all elements in the proper order.
    for (int i = 0; i < length; i++) {
      s.writeDouble(get(i));
    }
  }