return new PriorityQueue<>(c);
    }

    /**
     * {@link Stack}の新しいインスタンスを作成して返します。
     *
     * @param <E>
     *            {@link Stack}の要素型
     * @return {@link Stack}の新しいインスタンス
     * @see Stack#Stack()
     */
    public static <E> Stack<E> newStack() {
        return new Stack<>();
    }

    /**
     * {@link SynchronousQueue}の新しいインスタンスを作成して返します。
     *

      log.get()
          .log(
              Level.SEVERE,
              "SafeAtomicHelper is broken!",
              thrownAtomicReferenceFieldUpdaterFailure);
    }
  }

  /** Waiter links form a Treiber stack, in the {@link #waiters} field. */
  private static final class Waiter {
    static final Waiter TOMBSTONE = new Waiter(false /* ignored param */);

    @CheckForNull volatile Thread thread;

   * exception, every unchecked exception as an unchecked exception, and every error as an error. In
   * addition, the cause of any {@code ExecutionException} is wrapped in order to ensure that the
   * new stack trace matches that of the current thread.
   *
   * <p>Instances of {@code exceptionClass} are created by choosing an arbitrary public constructor

 * which are <i>not the caller's fault</i>. Doing so is <b>not recommended</b> because it is
 * misleading to future readers of the code and of stack traces. See <a
 * href="https://github.com/google/guava/wiki/ConditionalFailuresExplained">Conditional failures
 * explained</a> in the Guava User Guide for more advice. Notably, {@link Verify} offers assertions

 * which are <i>not the caller's fault</i>. Doing so is <b>not recommended</b> because it is
 * misleading to future readers of the code and of stack traces. See <a
 * href="https://github.com/google/guava/wiki/ConditionalFailuresExplained">Conditional failures
 * explained</a> in the Guava User Guide for more advice. Notably, {@link Verify} offers assertions