send JSON from Spring MVC to angularjs

I am trying to communicate spring MVC with angular, I send data from angular to spring but not the other way around, I have a login form, which I collect the data and send it to my JAVA project.

This works well, now I intend to return the same data to the index to show it below the form:

Here my JAVA code, the first function saveLogin receives the JSON well, when doing a test with the same data, I send them with Loadlogin_json(user); to the function that supposedly has to return it to the index to show it.

@Controller
public class RespuestaLogin {

    @RequestMapping(value = "/savelogin_json" , method = RequestMethod.POST,
            consumes="application/json",headers = "content-type=application/json")
     public @ResponseBody String saveLogin(HttpServletRequest request) throws IOException{
        BufferedReader reader = request.getReader();
        ObjectMapper mapper = new ObjectMapper();

        User user = mapper.readValue(reader, User.class);      
        Loadlogin_json(user);

        return "success";   
    }


    @RequestMapping(value = "/index", method = RequestMethod.POST)
    @ResponseBody
        public  void Loadlogin_json( User user)throws IOException {
            /*System.out.println("nombre: "+user.getName());


             return new ResponseEntity<User>(user, HttpStatus.OK);*/

        ObjectMapper mapper = new ObjectMapper();
        try {
            File json = new File("index.json");
            mapper.writeValue(json, user);
            System.out.println("Java object converted to JSON String, written to file");
            System.out.println(mapper.writeValueAsString(user));
             new ResponseEntity<ObjectMapper>(mapper, HttpStatus.OK);

        } catch (JsonGenerationException ex) {
            ex.printStackTrace();
        } catch (JsonMappingException ex) {
            ex.printStackTrace();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        }
}

Next I show the code of angular, like the LoginService of above works well, but the RespuestaLoginService no, I attach the code to see if you can give me a hand with why I do not pick up in angular the JSON sent .

var app= angular.module('login.loginService',[]);

app.factory('LoginService', ['$http','$q', function($http, $q){
        var self={
            login: function(datos){
                var dataObj = {
                        name : datos.usuario,
                        pass : datos.pass,
                };  

                var d=$q.defer();
                function genericSuccess (res) {
                      return res.data.data; // yes, really.
                    }
                var res= $http.post('savelogin_json', dataObj).then(function(success) {
                    return genericSuccess(success);
                  });

                return d.promise;
            }   
        };

        return self;
}]);

app.factory('RespuestaLoginService', ['$http','$q', function($http, $q){
    console.log("entra en angular");
    var self={
        respuestalogin: function(datos){

            var d=$q.defer();
            function genericSuccess (res) {
              return res.data.data; // yes, really.
            }

            $http.post("index",datos).then(function(success) {
                return genericSuccess(success);

            });

            console.log("FUE LLAMADO desde el servicio RespuestaLoginService login de angularjs");


            return d.promise;
        }

    };

    return self;


}]);