}

  /**
   * Saves the state to a stream (that is, serializes it). This merely wraps default serialization
   * within the monitor. The serialization strategy for items is left to underlying Queue. Note that
   * locking is not needed on deserialization, so readObject is not defined, just relying on
   * default.
   */
  private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
    monitor.enter();
    try {

    // way for it to return a false negative would be for the target value to jump around in the map
    // such that none of the subsequent iterations observed it, despite the fact that at every point
    // in time it was present somewhere int the map. This becomes increasingly unlikely as
    // CONTAINS_VALUE_RETRIES increases, though without locking it is theoretically possible.

 *       create a "fake" converter for a unit test. It is unnecessary (and confusing) to <i>mock</i>
 *       the {@code Converter} type using a mocking framework.
 *   <li>Extend this class and implement its {@link #doForward} and {@link #doBackward} methods.
 *   <li><b>Java 8+ users:</b> you may prefer to pass two lambda expressions or method references to

    /*
     * TODO(cpovirk): move ForwardingTestCase somewhere common, and use it to
     * test the forwarded methods
     */
  }

  @AndroidIncompatible // Mocking ExecutorService is forbidden there. TODO(b/218700094): Don't mock.
  public void testListeningDecorator_noWrapExecuteTask() {
    ExecutorService delegate = mock(ExecutorService.class);

   * uncommon to specify {@code concurrencyLevel(1)} in order to achieve more deterministic eviction
   * behavior.
   *
   * <p>Note that future implementations may abandon segment locking in favor of more advanced
   * concurrency controls.
   *
   * @return this {@code CacheBuilder} instance (for chaining)
   * @throws IllegalArgumentException if {@code concurrencyLevel} is nonpositive

    MemoizingSupplier(Supplier<T> delegate) {
      this.delegate = checkNotNull(delegate);
    }

    @Override
    @ParametricNullness
    public T get() {
      // A 2-field variant of Double Checked Locking.
      if (!initialized) {
        synchronized (this) {
          if (!initialized) {
            T t = delegate.get();
            value = t;
            initialized = true;
            return t;

  }

  /**
   * Saves the state to a stream (that is, serializes it). This merely wraps default serialization
   * within the monitor. The serialization strategy for items is left to underlying Queue. Note that
   * locking is not needed on deserialization, so readObject is not defined, just relying on
   * default.
   */
  private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
    monitor.enter();
    try {