android - Unable to receive response from the servlet -

i need retrieve control jsp response request fired earlier. problem facing not able response in jsp.

i have gone through few post , tried few suggestion none seems work me. please, point out mistake.

below try:

    protected void doget(httpservletrequest request,             httpservletresponse response) throws servletexception, ioexception {         log.info("in form doget");         request.setcharacterencoding("utf-8");         string selectedclass = request.getparameter("key");         log.info(selectedclass);         string[] section = null;         dbhandler dbhandler = new dbhandler();         dbhandler.makeconnection();         if (true == dbhandler.verifyconnection()) {             section = dbhandler.getsection(selectedclass);         }         (string str : section) {             log.info(str);         }         logger log;         if (null != section) {             request.setattribute(appconstants.section, section);         }         response.setheader("access-control-allow-origin", "*");         response.sendredirect("/reportfetcher/webcontent/firstjsp.jsp"); //      requestdispatcher view = request.getrequestdispatcher("/first.jsp"); //      view.forward(request, response);     } 

and below jsp part:

function funconchange() {     var index = document.detail.class.selectedindex;     var valueselected = document.detail.class.options[index].value;     var xhr = new xmlhttprequest();      xhr.onreadystatechange = function()     {         // check see if state change "request complete", ,         // there no server error (404 not found, 500 server error, etc)         if (xmlhttp.readystate==4 && xmlhttp.status==200)          {             var substring=xmlhttp.responsetext;             alert("alert dialog! gaurav");         }         if (xmlhttp.readystate == 404){             alert("404 error");         }         if (xmlhttp.readystate == 500){             alert("500 error");         }      }     xhr.open('get', 'http://localhost:8080/reportfetcher/formhandler?key='+encodeuricomponent(valueselected), true);     xhr.send(null);     return false; } 

i think doing right , suggested above should need forward request instead of redirecting request.

point going wrong making object of xmlhttprequest , referencing using variable xhr while making request, when taking care of response @ time checking status of variable xmlhttp , need replace variable xmlhttp xhr.

if face problem, feel free ask.