code: public static MockMethodDispatcher get(String identifier, Object instance) {
          if (instance == INSTANCE) {
              // Avoid endless loop if ConcurrentHashMap was redefined to check for being a mock.
              return null;
          } else {
              return INSTANCE.get(identifier);
          }
      }
docs: Get the dispatcher for a identifier.
  
  @param identifier identifier of the dispatcher
  @param instance instance that might be mocked
  
  @return dispatcher for the identifier