Populate dropdown

[joshua_8]

//jsp

 $("#year1").change(function(){
   var dataString = $(this).val();
    $.ajax({
            type: "POST",
            url:"Servlet",
            dataType: "json",
             data: {
              year :JSON.stringify(dataString)
              },
              success: function(result) {
              console.log(result);
         $('#category1').multipleSelect({
            filter: true,
            selectAll: false

        });  
    }
          });
          return false;
        });

//servlet
response.setContentType("text/html;charset=UTF-8");

PrintWriter out = response.getWriter();

String[] year = request.getParameterValues("year1"); //error

//Hi now my code is based on the id year1 dropdown value, the category1 dropdownlist will appear, but i got null pointer at that line.