return new NullRemovalListener<>();
  }

  /** Type-inferring factory method for creating a {@link QueuingRemovalListener}. */
  @GwtIncompatible // ConcurrentLinkedQueue
  static <K, V> QueuingRemovalListener<K, V> queuingRemovalListener() {
    return new QueuingRemovalListener<>();
  }

  /** Type-inferring factory method for creating a {@link CountingRemovalListener}. */

    return new NullRemovalListener<>();
  }

  /** Type-inferring factory method for creating a {@link QueuingRemovalListener}. */
  @GwtIncompatible // ConcurrentLinkedQueue
  static <K, V> QueuingRemovalListener<K, V> queuingRemovalListener() {
    return new QueuingRemovalListener<>();
  }

  /** Type-inferring factory method for creating a {@link CountingRemovalListener}. */

            computingSignal.countDown();
            startSignal.await();
            return computedObject;
          }
        };

    QueuingRemovalListener<Object, Object> listener = queuingRemovalListener();
    CacheBuilder<Object, Object> builder =
        createCacheBuilder().concurrencyLevel(1).removalListener(listener);
    LocalCache<Object, Object> map = makeLocalCache(builder);

            computingSignal.countDown();
            startSignal.await();
            return computedObject;
          }
        };

    QueuingRemovalListener<Object, Object> listener = queuingRemovalListener();
    CacheBuilder<Object, Object> builder =
        createCacheBuilder().concurrencyLevel(1).removalListener(listener);
    LocalCache<Object, Object> map = makeLocalCache(builder);

import static com.google.common.cache.TestingRemovalListeners.queuingRemovalListener;
import static com.google.common.truth.Truth.assertThat;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.cache.CacheLoader.InvalidCacheLoadException;
import com.google.common.cache.TestingRemovalListeners.QueuingRemovalListener;

import static com.google.common.cache.TestingRemovalListeners.queuingRemovalListener;
import static com.google.common.truth.Truth.assertThat;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.cache.CacheLoader.InvalidCacheLoadException;
import com.google.common.cache.TestingRemovalListeners.QueuingRemovalListener;

            if (shouldWait.get()) {
              computingLatch.await();
            }
            return key;
          }
        };
    QueuingRemovalListener<String, String> listener = queuingRemovalListener();

    LoadingCache<String, String> cache =
        CacheBuilder.newBuilder()
            .concurrencyLevel(1)
            .removalListener(listener)

    assertThat(keySet).containsExactly(3, 6);
  }

  public void testExpiration_invalidateAll() {
    FakeTicker ticker = new FakeTicker();
    QueuingRemovalListener<Integer, Integer> listener =
        TestingRemovalListeners.queuingRemovalListener();
    Cache<Integer, Integer> cache =
        CacheBuilder.newBuilder()
            .expireAfterAccess(1, MINUTES)
            .removalListener(listener)