@GwtIncompatible // ConcurrentLinkedQueue
  static class QueuingRemovalListener<K, V> extends ConcurrentLinkedQueue<RemovalNotification<K, V>>
      implements RemovalListener<K, V> {

    @Override
    public void onRemoval(RemovalNotification<K, V> notification) {
      add(notification);
    }
  }

  /**
   * {@link RemovalListener} that counts each {@link RemovalNotification} it receives, and provides

    Cache<Integer, Integer> cache =
        CacheBuilder.newBuilder()
            .removalListener(
                new RemovalListener<Integer, Integer>() {
                  @Override
                  public void onRemoval(RemovalNotification<Integer, Integer> notification) {
                    notifications.add(notification);
                  }
                })
            .build();
    cache.put(1, 2);

      RemovalListener<K, V> listener, Executor executor) {
    checkNotNull(listener);
    checkNotNull(executor);
    return (RemovalNotification<K, V> notification) ->
        executor.execute(() -> listener.onRemoval(notification));
  }

   * already been re-added.
   */
  // Technically should accept RemovalNotification<? extends K, ? extends V>, but because
  // RemovalNotification is guaranteed covariant, let's make users' lives simpler.
  void onRemoval(RemovalNotification<K, V> notification);

   * already been re-added.
   */
  // Technically should accept RemovalNotification<? extends K, ? extends V>, but because
  // RemovalNotification is guaranteed covariant, let's make users' lives simpler.
  void onRemoval(RemovalNotification<K, V> notification);

  private long currentTimeNanos() {
    return ticker.read();
  }

  private void alertListenerIfPresent(K key, V value, RemovalCause cause) {
    if (removalListener != null) {
      removalListener.onRemoval(RemovalNotification.create(key, value, cause));
    }
  }

  @SuppressWarnings("GoodTime") // timestamps as numeric primitives
  private V load(K key) throws ExecutionException {
    long startTime = ticker.read();

    int[] stats = new int[4];

    RemovalListener<Integer, Integer> countingListener =
        new RemovalListener<Integer, Integer>() {
          @Override
          public void onRemoval(RemovalNotification<Integer, Integer> notification) {
            switch (notification.getCause()) {
              case EXPIRED:
                stats[0]++;
                break;
              case EXPLICIT:

    AtomicInteger totalSum = new AtomicInteger();

    RemovalListener<Integer, AtomicInteger> removalListener =
        new RemovalListener<Integer, AtomicInteger>() {
          @Override
          public void onRemoval(RemovalNotification<Integer, AtomicInteger> notification) {
            if (notification.wasEvicted()) {
              evictionCount.incrementAndGet();
              totalSum.addAndGet(notification.getValue().get());

    RuntimeException e = new RuntimeException();
    RemovalListener<Object, Object> listener =
        new RemovalListener<Object, Object>() {
          @Override
          public void onRemoval(RemovalNotification<Object, Object> notification) {
            throw e;
          }
        };

    CacheBuilder<Object, Object> builder = createCacheBuilder().removalListener(listener);

          return new SimpleStatsCounter();
        }
      };

  enum NullListener implements RemovalListener<Object, Object> {
    INSTANCE;

    @Override
    public void onRemoval(RemovalNotification<Object, Object> notification) {}
  }

  enum OneWeigher implements Weigher<Object, Object> {
    INSTANCE;

    @Override
    public int weigh(Object key, Object value) {