Problems with applet-servlet communication

[Serethos]

public class HelloServlet extends HttpServlet
{

/* only for test purposes !
     public void doGet(HttpServletRequest request, HttpServletResponse response)
     {
           try
           {
                 FileWriter fw = new FileWriter(new File("test.txt"));
                 fw.write("doGet");
                 fw.close();
           }
           catch (IOException e)
           {
                 
           }
     }
*/

     public void doPost(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, IOException
     {
           try {
                 response.setContentType("application/x-java-serialized-object");

                 InputStream in = request.getInputStream();
                 ObjectInputStream inputFromApplet = new ObjectInputStream(in);
                 String echo = (String) inputFromApplet.readObject();
                 
                 FileWriter fw = new FileWriter(new File("test.txt"));
                 fw.write(echo);

                 fw.close();


           } catch (Exception e) {
                 e.printStackTrace();
           }
     }

}




now the applet, which submits a string:


public class HelloApplet extends Applet
{

     public void init()
     {
           onSendData();
     }

     /**
      * Get a connection to the servlet.
      */
     private URLConnection getServletConnection()
           throws MalformedURLException, IOException {

           // Connection zum Servlet ýffnen
           URL urlServlet = new URL(getCodeBase(), "hello");
           URLConnection con = urlServlet.openConnection();

           // konfigurieren
           con.setDoInput(true);
           con.setDoOutput(true);
           con.setUseCaches(false);
           con.setRequestProperty(
                 "Content-Type",
                 "application/x-java-serialized-object");

           // und zurýckliefern
           return con;
     }

     private void onSendData() {
           try {
                 // get input data for sending
                 String input = "User 1            1:30";

                 // send data to the servlet
                 URLConnection con = getServletConnection();
                 OutputStream outstream = con.getOutputStream();
                 ObjectOutputStream oos = new ObjectOutputStream(outstream);
                 oos.writeObject(input);
                 oos.flush();
                 oos.close();

                 

           } catch (Exception ex) {
                 ex.printStackTrace();
           }
     }
     
}



now i have several problems and questions.
first i get an exception:


java.net.UnknownServiceException: protocol doesn't support output
     at java.net.URLConnection.getOutputStream(Unknown Source)
     at HelloApplet.onSendData(HelloApplet.java:54)
     at HelloApplet.init(HelloApplet.java:19)
     at sun.applet.AppletPanel.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
[code]

[Serethos]

grrrr, very sorry, posted too early, the intro is missing  :-/


my applet needs to write a file onto the server using a servlet

therefore i have written two classes (with a little help of i-net articles) -->


first the server file :