if (ref != null) {
        ref.clear();
      }
    }
  }

  /**
   * Poke into the Cache internals to simulate garbage collection of the given key. This assumes
   * that the given entry is a weak or soft reference, and throws an IllegalStateException if that
   * assumption does not hold.
   */
  static <K, V> void simulateKeyReclamation(Cache<K, V> cache, K key) {
    ReferenceEntry<K, V> entry = getReferenceEntry(cache, key);

      if (ref != null) {
        ref.clear();
      }
    }
  }

  /**
   * Poke into the Cache internals to simulate garbage collection of the given key. This assumes
   * that the given entry is a weak or soft reference, and throws an IllegalStateException if that
   * assumption does not hold.
   */
  static <K, V> void simulateKeyReclamation(Cache<K, V> cache, K key) {
    ReferenceEntry<K, V> entry = getReferenceEntry(cache, key);