android/guava/src/com/google/common/graph/MapIteratorCache.java
protected V getIfCached(@NullableDecl Object key) {
    Entry<K, V> entry = entrySetCache; // store local reference for thread-safety

    // Check cache. We use == on purpose because it's cheaper and a cache miss is ok.
    if (entry != null && entry.getKey() == key) {
      return entry.getValue();
    }
    return null;
  }
protected V getIfCached(@NullableDecl Object key) {
    Entry<K, V> entry = entrySetCache; // store local reference for thread-safety

    // Check cache. We use == on purpose because it's cheaper and a cache miss is ok.
    if (entry != null && entry.getKey() == key) {
      return entry.getValue();
    }
    return null;
  }
Internal methods ('protected' is still package-visible, but treat as only subclass-visible)