title: empty response in ajax call
body: <pre><code>function callQueAjax()
                              {
                              var str = $("#addNewQues").serialize();
                              $.ajax({
                                              type : "POST",
                                              data : JSON.stringify(str),
                                              url : "postNewQues",
                                              dataType: "json",
                                              contentType: "application/json",
                                              success : function(res) {
                                              //alert("yay");
                                              alert("res&gt;&gt;&gt;&gt;&gt;"+res);
  
                                              },
                                              error : function(e) {
                                                  alert("error" + e);
  
                                              }
                                              });
                              }
  </code></pre>
  
  <p>when i am sending the form data it is passing correctly to my controller, but in the response all the fields are null,plz help to get the correct data in the response.And if i remove <code>contentType: "application/json",</code> i am getting  400 Bad request as error.
  Controller code:</p>
  
  <pre><code>@RequestMapping(value = "/postNewQues", method = RequestMethod.POST)
      public @ResponseBody
      String submitNewQue(@ModelAttribute("EEAQBean") EEAQueBean eEAQBean) {
          // System.out.println("Obj.getReqTitle()&gt;&gt;&gt;&gt;&gt;&gt;"+Obj.getReqTitle());
          // Obj.getReqTitle();
          logger.info("IN Controller EEAss");
          logger.info("eEAQBean &gt;&gt;&gt; "+eEAQBean.getReqId()+" &gt;&gt;&gt;&gt;&gt; "+eEAQBean.getQueOrder());
  
          HashMap&lt;String, Object&gt; data = new HashMap&lt;String, Object&gt;();
          List&lt;EEAQueBean&gt; addNewQueList = new ArrayList&lt;EEAQueBean&gt;();
  
          // Long addNewReqId =0L;
          String addNewQueVal = "";
          String addNewQueCode = "";
  
          try {
  
              addNewQueCode = eeaServiceImpl.insertAddNewQueData(eEAQBean);
  
              eEAQBean.setAddNewQueCode(addNewQueCode);
              addNewQueList.add(eEAQBean);
              data.put("addNewQueList", addNewQueList);
              ObjectMapper mapper = new ObjectMapper();
              addNewQueVal = mapper.writeValueAsString(data);
              logger.info("addNewQueVal &gt;&gt;&gt;&gt;&gt; " + addNewQueVal);
          } catch (Exception e) {
              e.printStackTrace();
          } finally {
  
          }
          return addNewQueVal;
      }
  </code></pre>