| ((source[offset + 3] & 0xFF) << 24);
  }

  /**
   * Indicates that the loading of Unsafe was successful and the load and store operations will be
   * very efficient. May be useful for calling code to fall back on an alternative implementation
   * that is slower than Unsafe.get/store but faster than the pure-Java mask-and-shift.
   */
  static boolean usingUnsafe() {

        | ((source[offset + 3] & 0xFF) << 24);
  }

  /**
   * Indicates that the loading of Unsafe was successful and the load and store operations will be
   * very efficient. May be useful for calling code to fall back on an alternative implementation
   * that is slower than Unsafe.get/store but faster than the pure-Java mask-and-shift.
   */
  static boolean usingUnsafe() {

            return (result == NULL_PLACEHOLDER) ? null : result;
          },
          Collector.Characteristics.UNORDERED);

  /**
   * A collector that takes a stream containing exactly one element and returns that element. The
   * returned collector throws an {@code IllegalArgumentException} if the stream consists of two or
   * more elements, and a {@code NoSuchElementException} if the stream is empty.
   */

          }
        });
    assertTrue(map.isEmpty());
  }

  // ----------------------------------------------------------------
  // Test that interrupts result in RuntimeException, not InterruptedException.
  // Trickier than it looks, because runFinalization swallows interrupts.
  // ----------------------------------------------------------------

  class Interruptenator extends Thread {

    // First ensure that our classloaders are initializing the correct helper versions
    checkHelperVersion(getClass().getClassLoader(), "UnsafeAtomicHelper");
    checkHelperVersion(NO_UNSAFE, "SafeAtomicHelper");
    checkHelperVersion(NO_ATOMIC_REFERENCE_FIELD_UPDATER, "SynchronizedHelper");

    // Run the corresponding AbstractFutureTest test method in a new classloader that disallows
    // certain core jdk classes.

  /** Create the FRQ in a method that goes out of scope so that we're sure it will be reclaimed. */
  private void weaklyReferenceQueue() {
    frq = new FinalizableReferenceQueue();
    queueReference = new WeakReference<>(frq.queue);

    /*
     * Queue and clear a reference for good measure. We test later on that
     * the finalizer thread stopped, but we should test that it actually
     * started first.
     */

    // First ensure that our classloaders are initializing the correct helper versions
    checkHelperVersion(getClass().getClassLoader(), "UnsafeAtomicHelper");
    checkHelperVersion(NO_UNSAFE, "SafeAtomicHelper");
    checkHelperVersion(NO_ATOMIC_REFERENCE_FIELD_UPDATER, "SynchronizedHelper");

    // Run the corresponding AbstractFutureTest test method in a new classloader that disallows
    // certain core jdk classes.

    return File.createTempFile("test", null, getTempDir());
  }

  /** Returns a byte array of length size that has values 0 .. size - 1. */
  static byte[] newPreFilledByteArray(int size) {
    return newPreFilledByteArray(0, size);
  }

  /** Returns a byte array of length size that has values offset .. offset + size - 1. */
  static byte[] newPreFilledByteArray(int offset, int size) {