Servlet+ajax+javascript обновление формы из базы

public class Servlet_goskom_cat extends HttpServlet {
 
    public Statement stmt = null;
    public Connection con = null;
    public ResultSet rs = null;
    public URLConnection  fromGosMet = null;
    
       public void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException, ClassNotFoundException, SQLException, InstantiationException, IllegalAccessException {
 
    }
       
        public Servlet_goskom_cat() throws ClassNotFoundException, SQLException, MalformedURLException, IOException
    {
        Class.forName("org.postgresql.Driver");
        con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/postgres","postgres", "postgres");
        stmt = con.createStatement();
        
 
    }
      
    @Override
    public void init() throws ServletException {
        super.init(); //To change body of generated methods, choose Tools | Templates.
    }
    
 
       @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try {
            processRequest(request, response);
        } catch (ClassNotFoundException | SQLException | InstantiationException | IllegalAccessException ex) {
            Logger.getLogger(Servlet_goskom_cat.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
 
    
    protected JSONObject getNameUgms() throws SQLException, ClassNotFoundException, IOException
    {
       
               
                JSONObject resultJson = new JSONObject();
                JSONArray ar = new JSONArray();
                rs = stmt.executeQuery("select Ugms from Ugms");
                while(rs.next())              
                   {
                       ar.add(rs.getString(1));
                   }
               
               resultJson.put("dataFin", ar);
               
               System.out.println(resultJson);
               
               //
               
               
               
               return resultJson;
        
    }
    
 
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try {
            processRequest(request, response);
        } catch (ClassNotFoundException | SQLException | InstantiationException | IllegalAccessException ex) {
            Logger.getLogger(Servlet_goskom_cat.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
 
   
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>