@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.)
   *

     * read operations anyway:
     *
     * - All (unsynchronized) read operations must first read the "count" field, and should not
     * look at table entries if it is 0.
     *
     * - All (synchronized) write operations should write to the "count" field after structurally
     * changing any bin. The operations must not take any action that could even momentarily

  private TestSuppressor suppressor;

  @Override
  protected void setUp() throws Exception {
    suppressor = new TestSuppressor();
  }

  @AndroidIncompatible // TODO(cpovirk): Look up Build.VERSION.SDK_INT reflectively.
  public void testCreate() {
    assertThat(Closer.create().suppressor).isInstanceOf(Closer.SuppressingSuppressor.class);
  }

  public void testNoExceptionsThrown() throws IOException {

               * The next combination is
               *
               * {0, 1, ..., bitToFlip - firstSetBit - 2, bitToFlip, ...}
               *
               * This is lexicographically next if you look at the combinations in descending order
               * e.g. {2, 1, 0}, {3, 1, 0}, {3, 2, 0}, {3, 2, 1}, {4, 1, 0}...
               */

              bits.set(0, bitToFlip - firstSetBit - 1);

   */
  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
  // @IgnoreJRERequirement is not necessary because this compiles down to a constant.
  // (which is fortunate because Animal Sniffer doesn't look for @IgnoreJRERequirement on fields)
  static final int SPLITERATOR_CHARACTERISTICS =
      Spliterator.IMMUTABLE | Spliterator.NONNULL | Spliterator.ORDERED;

  ImmutableCollection() {}

                  }
                }
              }));
    }

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

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

   * the computation -- makes sense, and if we don't convert it, the user still has to write a
   * try-catch block.
   *
   * If you think you would use this method, let us know. You might also look into the
   * Fork-Join framework: http://docs.oracle.com/javase/tutorial/essential/concurrency/forkjoin.html
   */

  private TestSuppressor suppressor;

  @Override
  protected void setUp() throws Exception {
    suppressor = new TestSuppressor();
  }

  @AndroidIncompatible // TODO(cpovirk): Look up Build.VERSION.SDK_INT reflectively.
  public void testCreate() {
    assertThat(Closer.create().suppressor).isInstanceOf(Closer.SuppressingSuppressor.class);
  }

  public void testNoExceptionsThrown() throws IOException {

   * GWT SortedMap implementation that we delegate to throws
   * NullPointerException if the comparator does. Since our construction
   * methods ensure that null is never present in the map, it's OK for the
   * comparator to look for it wherever it wants.
   *
   * Note that we do NOT touch the comparator returned by comparator(), which
   * should be identical to the one the user passed in. We touch only the