code: @SuppressWarnings("unchecked")
      public static <T extends Config> T remove(Object key) {
          return (T) CACHE.remove(key);
      }
docs: Removes the cached instance for the given key if it is present.
  
  <p>Returns previous instance associated to the given key in the cache,
  or <code>null</code> if the cache contained no instance for the given key.
  
  <p>The cache will not contain the instance for the specified key once the
  call returns.
  
  @param <T>   type of the interface.
  @param key   key whose instance is to be removed from the cache.
  @return      the previous instance associated with <code>key</code>, or
  <code>null</code> if there was no instance for <code>key</code>.