code: public boolean containsKey(final long key) {
          int index = longHash(key, mask);
          while (null != values[index]) {
              if (key == keys[index]) {
                  return true;
              }
              index = ++index & mask;
          }
          return false;
      }
docs: Overloaded version of {@link Map#containsKey(Object)} that takes a primitive long key.
  
  @param key for indexing the {@link Map}
  @return true if the key is found otherwise false.