for (Integer node : graph.nodes()) {
                    Set<Integer> unused = graph.successors(node);
                  }
                  /*
                   * Also look up an earlier node so that, if the graph is using MapRetrievalCache,
                   * we read one of the fields declared in that class.
                   */
                  Set<Integer> unused = graph.successors(first);

  }

  public void testManualServiceFailureIdempotence() {
    ManualSwitchedService service = new ManualSwitchedService();
    /*
     * Set up a RecordingListener to perform its built-in assertions, even though we won't look at
     * its state history.
     */
    RecordingListener unused = RecordingListener.record(service);
    service.startAsync();
    service.notifyFailed(new Exception("1"));

    @Override
    public String toString() {
      return getKey() + "=" + getValue();
    }
  }

  // TODO(fry): Separate logic for consistency between emul and nonemul implementation.
  // TODO(fry): Look into Maps.KeySet and Maps.Values, which can ideally be reused here but are
  // currently only package visible.
  abstract class AbstractCacheSet<T> extends AbstractSet<T> {
    final ConcurrentMap<?, ?> map;

   * elements directly and null for empty positions, we store indices of the keys in the hash table,
   * and ABSENT for empty positions.  We then look up the keys in alternatingKeysAndValues.
   *
   * (The index actually stored is the index of the key in alternatingKeysAndValues, which is
   * double the index of the entry in entrySet.asList.)
   *

        policy.handlePotentialDeadlock(exception);
        return;
      }
      // Otherwise, it's the first time seeing this lock relationship. Look for
      // a path from the acquiredLock to this.
      Set<LockGraphNode> seen = Sets.newIdentityHashSet();
      ExampleStackTrace path = acquiredLock.findPathTo(this, seen);

      if (path == null) {

  //
  // 1. What about leaving/unlocking? Are you going to do
  //    guard.enter() paired with monitor.leave()? That might get
  //    confusing. It's nice for the finally block to look as close as
  //    possible to the thing right before the try. You could have
  //    guard.leave(), but that's a little odd as well because the
  //    guard doesn't have anything to do with leaving. You can't

   * }</pre>
   */
  private static final SuccessorsFunction<Character> TREE =
      createDirectedGraph("hd", "he", "hg", "da", "db", "dc", "gf");

  /**
   * Two disjoint tree-shaped graphs that look as follows (all edges are directed facing downwards):
   *
   * <pre>{@code
   * a   c
   * |   |
   * |   |
   * b   d
   * }</pre>
   */

              | (1L << (41 - 2))
              | (1L << (43 - 2))
              | (1L << (47 - 2))
              | (1L << (53 - 2))
              | (1L << (59 - 2))
              | (1L << (61 - 2));
      // Look up n within the mask.
      return ((mask >> ((int) n - 2)) & 1) != 0;
    }

    if ((SIEVE_30 & (1 << (n % 30))) != 0) {
      return false;
    }
    if (n % 7 == 0 || n % 11 == 0 || n % 13 == 0) {

                  }
                }
              }));
    }

    @VisibleForTesting
    void addShutdownHook(Thread hook) {
      Runtime.getRuntime().addShutdownHook(hook);
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // TODO
  private static void useDaemonThreadFactory(ThreadPoolExecutor executor) {
    executor.setThreadFactory(

 *
 * <pre>
 * interface Book {...}
 * public class Books {
 *   public static Book hardcover(String title) {...}
 *   public static Book paperback(String title) {...}
 * }
 * </pre>
 *
 * <p>And all the created {@code Book} instances can be tested with:
 *
 * <pre>
 * new ClassSanityTester()
 *     .forAllPublicStaticMethods(Books.class)
 *     .thatReturn(Book.class)