String deskey = "aaa";
        
        ByteArrayOutputStream key_file_out = new ByteArrayOutputStream (); 
        ObjectOutputStream key_object_out = new ObjectOutputStream(key_file_out);
        key_object_out.writeObject(deskey);
        
        byte[] a =(key_file_out.toByteArray());
        
        ByteArrayInputStream input = new ByteArrayInputStream(a);
        ObjectInputStream obj = new ObjectInputStream(input);
        String s =(String) obj.readObject();
        System.out.println(s);