Calling a dos shell with a servlet

Question

I am using the code below to call a dos shell using a servlet. will you please tell what is wrong with my code. thank you.
public class ResponseServlet extends HttpServlet {
public void doGet (HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException
PrintWriter out = response.getWriter();
// then write the data of the response
String username = request.getParameter("username");
if ( username != null && username.length() > 0 ) {
     Runtime rt = Runtime.getRuntime();
     rt.exec("C:\\WINNT\\system32\\CMD.EXE");
public String getServletInfo() {
return "The Response servlet says hello.";

Answer 1

Response code 503. "Service unavailable". Sounds like a server configuration issue.