code: public Interceptors add(Interceptor globalActionInterceptor) {
  		if (globalActionInterceptor == null) {
  			throw new IllegalArgumentException("globalActionInterceptor can not be null.");
  		}
  		InterceptorManager.me().addGlobalActionInterceptor(globalActionInterceptor);
  		return this;
  	}
docs: The same as addGlobalActionInterceptor. It is used to compatible with earlier version of jfinal