code: public static <T> Maybe<List<T>> values(String key, Class<T> vClazz) {
          return values(CacheService.CACHE_CONFIG_BEAN, key, vClazz);
      }
docs: retrieval all the values in the cache map
  
  @param key    the key of the cached map
  @param vClazz the value's class
  @param <T>    the value's generic type
  @return the whole list if exists or null if the key does not exist.return