for (int i = 0; i < 8; i++) {
      limiter.acquire(); // #1
    }
    stopwatch.sleepMillis(500); // #2: to repay for the last acquire
    stopwatch.sleepMillis(4000); // #3: becomes cold again
    for (int i = 0; i < 8; i++) {
      limiter.acquire(); // // #4
    }
    stopwatch.sleepMillis(500); // #5: to repay for the last acquire

      }
      // The future may complete during or before the call to getPendingToString, so we use null
      // as a signal that we should try checking if the future is done again.
      if (!isNullOrEmpty(pendingDescription)) {
        builder.append("PENDING, info=[").append(pendingDescription).append("]");
      } else if (isDone()) {
        addDoneString(builder);
      } else {

   * expanded mask.  We do not try to detect or remove such cells,
   * under the assumption that for long-running instances, observed
   * contention levels will recur, so the cells will eventually be
   * needed again; and for short-lived ones, it does not matter.
   */

  /**
   * Padded variant of AtomicLong supporting only raw accesses plus CAS. The value field is placed
   * between pads, hoping that the JVM doesn't reorder them.

        // empty instance already generated
        if (emptyInstanceGenerated.get(type.getType()).intValue() == freshness.get()) {
          // same freshness, generate again.
          return invokeGeneratorMethod(emptyGenerate);
        } else {
          // Cannot use empty generator. Proceed with other generators.
        }
      } else {

    // moving the hole down. In most cases this reduces the number of
    // comparisons with toTrickle, but in some cases we will need to bubble it
    // all the way up again.
    int vacated = heap.fillHoleAt(index);
    // Try to see if toTrickle can be bubbled up min levels.
    int bubbledTo = heap.bubbleUpAlternatingLevels(vacated, toTrickle);
    if (bubbledTo == vacated) {

    // always point to "a".
    for (String string : cycle) {
      assertEquals("a", string);
      break;
    }

    assertEquals("[a, b] (cycled)", cycle.toString());
  }

  // Again, the exhaustive tests are in IteratorsTest
  public void testConcatIterable() {
    List<Integer> list1 = newArrayList(1);
    List<Integer> list2 = newArrayList(4);

        transform(errorInput, newOneTimeErrorThrower(), directExecutor());
    errorInput.set(0);

    runGetIdempotencyTest(errorComposedFuture, MyError.class);

    /*
     * Try again when the input's value is already filled in, since the flow is
     * slightly different in that case.
     */
    exceptionComposedFuture =
        transform(exceptionInput, newOneTimeExceptionThrower(), directExecutor());

   * concurrency than full synchronization. Defaults to 4.
   *
   * <p><b>Note:</b> Prior to Guava release 9.0, the default was 16. It is possible the default will
   * change again in the future. If you care about this value, you should always choose it
   * explicitly.
   *
   * @throws IllegalArgumentException if {@code concurrencyLevel} is nonpositive

      while (true) {
        /*
         * requireNonNull is safe because visitedNodes isn't cleared until this method calls
         * endOfData() (after which this method is never called again).
         */
        requireNonNull(visitedNodes);
        while (successorIterator.hasNext()) {
          N otherNode = successorIterator.next();
          if (!visitedNodes.contains(otherNode)) {

 * test methods in these degenerate classloaders.
 */

public class AbstractFutureFallbackAtomicHelperTest extends TestCase {

  // stash these in static fields to avoid loading them over and over again (speeds up test
  // execution significantly)

  /**
   * This classloader disallows {@link sun.misc.Unsafe}, which will prevent us from selecting our
   * preferred strategy {@code UnsafeAtomicHelper}.
   */