private void setPredecessor(int entry, int pred) {
    long predMask = ~0L << 32;
    setLink(entry, (link(entry) & ~predMask) | ((long) (pred + 1) << 32));
  }

  private void setSucceeds(int pred, int succ) {
    if (pred == ENDPOINT) {
      firstEntry = succ;
    } else {
      setSuccessor(pred, succ);
    }

    if (succ == ENDPOINT) {
      lastEntry = pred;
    } else {

 *
 * <p>The following code:
 *
 * <pre>{@code
 * ListMultimap<String, String> multimap = ArrayListMultimap.create();
 * for (President pres : US_PRESIDENTS_IN_ORDER) {
 *   multimap.put(pres.firstName(), pres.lastName());
 * }
 * for (String firstName : multimap.keySet()) {
 *   List<String> lastNames = multimap.get(firstName);
 *   out.println(firstName + ": " + lastNames);
 * }
 * }</pre>
 *
 * ... produces output such as:
 *

    if (waiters == 0) {
      // unlink guard from activeGuards
      for (Guard p = activeGuards, pred = null; ; pred = p, p = p.next) {
        if (p == guard) {
          if (pred == null) {
            activeGuards = p.next;
          } else {
            pred.next = p.next;
          }
          p.next = null; // help GC
          break;
        }
      }
    }
  }

  }

  private void setPredecessor(int entry, int pred) {
    requirePredecessors()[entry] = pred + 1;
  }

  private void setSucceeds(int pred, int succ) {
    if (pred == ENDPOINT) {
      firstEntry = succ;
    } else {
      setSuccessor(pred, succ);
    }

    if (succ == ENDPOINT) {
      lastEntry = pred;
    } else {
      setPredecessor(succ, pred);
    }
  }

  @Override

    /** Constructor for the header node. */
    AvlNode() {
      this.elem = null;
      this.elemCount = 1;
    }

    // For discussion of pred() and succ(), see the comment on the pred and succ fields.

    private AvlNode<E> pred() {
      return requireNonNull(pred);
    }

    private AvlNode<E> succ() {
      return requireNonNull(succ);
    }

 *
 * <pre>{@code
 * ListenableFuture<Boolean> adminIsLoggedIn =
 *     FluentFuture.from(usersDatabase.getAdminUser())
 *         .transform(User::getId, directExecutor())
 *         .transform(ActivityService::isLoggedIn, threadPool)
 *         .catching(RpcException.class, e -> false, directExecutor());
 * }</pre>
 *
 * <h3>Alternatives</h3>
 *
 * <h4>Frameworks</h4>
 *

   *
   * <pre>
   * for (Foo foo : foos) {
   *   try {
   *     foo.bar();
   *   } catch (BarException | RuntimeException | Error t) {
   *     failure = t;
   *   }
   * }
   * if (failure != null) {
   *   throwIfInstanceOf(failure, BarException.class);
   *   throwIfUnchecked(failure);
   *   throw new AssertionError(failure);
   * }
   * </pre>
   *
   * @since 20.0
   */

   *
   * <pre>
   * for (Foo foo : foos) {
   *   try {
   *     foo.bar();
   *   } catch (BarException | RuntimeException | Error t) {
   *     failure = t;
   *   }
   * }
   * if (failure != null) {
   *   throwIfInstanceOf(failure, BarException.class);
   *   throwIfUnchecked(failure);
   *   throw new AssertionError(failure);
   * }
   * </pre>
   *
   * @since 20.0
   */

 * then Lock B, while another thread acquires Lock B, and then Lock A:
 *
 * <pre>
 * Thread1: acquire(LockA) --X acquire(LockB)
 * Thread2: acquire(LockB) --X acquire(LockA)
 * </pre>
 *
 * <p>Neither thread will progress because each is waiting for the other. In more complex
 * applications, cycles can arise from interactions among more than 2 locks:
 *
 * <pre>
 * Thread1: acquire(LockA) --X acquire(LockB)

 * presented below:
 *
 * <pre>
 * void runManyThings({@literal List<ThingToRun>} thingsToRun) {
 *   for (ThingToRun thingToRun : thingsToRun) {
 *     thingToRun.run(); // say this may throw an exception, but you want to
 *                       // always run all thingsToRun
 *   }
 * }
 * </pre>
 *
 * <p>This is what the code would become:
 *
 * <pre>