Lock windows desktop from Java after timeout
javax.swing.Timer tim = new javax.swing.Timer(1000, new ActionListener() {
   public void actionPerformed(ActionEvent e) {
   System.out.println("CARD NOT PRESENT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
   // LOCK SCREEN
   Runtime rt = Runtime.getRuntime();
   Process pr = rt.exec("%windir%/System32/rundll32.exe user32.dll,LockWorkStation");
   }
});

Runtime.getRuntime().exec("C:\Windows\System32\rundll32.exe user32.dll,LockWorkStation");