public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
Mode mode = ModeSelector.getMode(req.getParameter("mode"));
Modules modules = null;
try {
modules = new Modules(req, mode);
} catch (ModuleNotFoundException e) {
resp.setContentType("text/plain");
PrintWriter out = resp.getWriter();
out.println(e.getMsg());
return;