return copy;
  }

  /**
   * Not supported. Use {@link #eraseAll} instead.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Use {@link #eraseAll}
   */
  @DoNotCall("Always throws UnsupportedOperationException")
  @Override
  @Deprecated
  public void clear() {
    throw new UnsupportedOperationException();
  }

    return copy;
  }

  /**
   * Not supported. Use {@link #eraseAll} instead.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Use {@link #eraseAll}
   */
  @DoNotCall("Always throws UnsupportedOperationException")
  @Override
  @Deprecated
  public void clear() {
    throw new UnsupportedOperationException();
  }