Java GuardedObject create and save

import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.security.Guard;
import java.security.GuardedObject;
import java.util.PropertyPermission;

public class Main {
   public static void main(String[] args) throws Exception {
      Guard guard = new PropertyPermission("usr.home", "read");
      String pass = new String("123456");
      GuardedObject go = new GuardedObject(pass, guard);
      ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("pass"));
      oos.writeObject(go);// w w w.jav  a2 s . c o m
   }
}