如何在阿贾克斯打电话给杰森市？

Their are many examples on google but they are not helpful, i'm getting this error VM169:1 Uncaught SyntaxError: Unexpected token < in JSON at position 0 at JSON.parse ()

here 0 is GET and POST 1 is Json in jquery file

$("#stateID").change(function(){
            var stateID= $(this).val();
            if(stateID != ""){
                var stateJson=xAjaxCall("ajax/state-city-json/"+stateID,null,0,1);
                if(stateJson != null && !xIsEmptyJSON(stateJson)){
                    xBindJSONtoCombo(stateJson, $("#cityID"));
                }
            }
        }); 

My controller

@ResponseBody          //get State-city-json
    @RequestMapping(value="/ajax/state-city-json/{stateID}",method = RequestMethod.GET)
    public String getStateJson(@PathVariable("stateID") int stateID){
        System.out.println("Ajax call city");
        return JSONObject.toJSONString(userRegistrationCommonService.getCityMap(stateID));
    }