docs: @Override
  	protected Object getHandler(String serviceName) {
  		Object handler = handlerMap.get(serviceName);
  		if (handler == null) {
  			logger.error("Service '{}' is not registered in this multi-server", serviceName);
  			throw new RuntimeException("Service '" + serviceName + "' does not exist");
  		}
  		return handler;
  	}