access denied (java.util.PropertyPermission user.home read)

java.security.AccessControlException: access denied (java.util.PropertyPermission user.home read)

    at java.security.AccessControlContext.checkPermission(Unknown Source)

    at java.security.AccessController.checkPermission(Unknown Source)

    at java.lang.SecurityManager.checkPermission(Unknown Source)

    at java.lang.SecurityManager.checkPropertyAccess(Unknown Source)

    at java.lang.System.getProperty(Unknown Source)

    at KeyReader.init(keyreader.java:14)

    at sun.applet.AppletPanel.run(Unknown Source)

    at java.lang.Thread.run(Unknown Source)

Jeg får denne fejl nå jeg kører min signed applet.

Hvad skal jeg gøre for at den ikke gør det mere?

Kode:

import java.awt.*;
import javax.swing.*;
import java.io.*;
import java.net.*;

public class KeyReader extends JApplet {
String s;
    public void init() {
       
        try {
            String separator = System.getProperty("file.separator");
            String serfil = getParameter("serfil");

        FileReader fil = new FileReader(System.getProperty("user.home") + File.separator + serfil);
            System.out.println(System.getProperty("user.home") + File.separator + serfil);
            s = "";


            BufferedReader ind = new BufferedReader(fil);

        String linje = ind.readLine();
            while (linje != null)
              {
              s = s + linje;
              linje = ind.readLine();
              }


    try {
            String hyperlink = getParameter("hyperlink");           
            URL url = new URL(hyperlink + "?key=" + s);
            HttpURLConnection con = (HttpURLConnection) url.openConnection();
            con.setRequestMethod("POST");
            String info = "key=" + s;
            con.setDoOutput(true);
            con.getOutputStream().write(info.getBytes());
            con.connect();
            getAppletContext().showDocument(url);
            if (con.getResponseCode() != HttpURLConnection.HTTP_OK) {
                System.err.println("POST failed");
            }
            con.disconnect();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
           
                   
           
        }
        catch (IOException e) {
            if (e.getMessage() != null)
                System.out.println("e=" + e);
        }


    }

}