*
     * @param <E> the element type of {@link PriorityQueue}
     * @return a new instance of {@link PriorityQueue}
     * @see PriorityQueue#PriorityQueue()
     */
    public static <E> PriorityQueue<E> newPriorityQueue() {
        return new PriorityQueue<>();
    }

    /**
     * Creates and returns a new instance of {@link PriorityQueue}.
     *
     * @param <E> the element type of {@link PriorityQueue}

   *     in 15.0)
   */
  @SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
  public static <E extends Comparable> PriorityQueue<E> newPriorityQueue() {
    return new PriorityQueue<>();
  }

  /**
   * Creates a {@code PriorityQueue} containing the given elements.
   *

   *     in 15.0)
   */
  @SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
  public static <E extends Comparable> PriorityQueue<E> newPriorityQueue() {
    return new PriorityQueue<>();
  }

  /**
   * Creates a {@code PriorityQueue} containing the given elements.
   *