ArrayList<Record> highScoreList;
highScoreList = new ArrayList<>();
highScoreReading(highScoreList);
window.setOnCloseRequest(e -> {
            e.consume();
            highScoreSaving(highScoreList);
            window.close();
});

private void highScoreReading(ArrayList<Record> highScoreList){
        try{
            ObjectInputStream ois=new ObjectInputStream(new FileInputStream("highscore"));
            while(highScoreList.add((Record)ois.readObject())){/*semmi*/        }
        } catch (IOException io){
        } catch (ClassNotFoundException cnfe){
        }
    }

    private static void highScoreSaving(ArrayList<Record> highScoreList){
        //először rendezünk
        Collections.sort(highScoreList, new ScoreComparator());
        Collections.reverse(highScoreList);
        try {
            ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("highscore"));
            Iterator<Record> it = highScoreList.iterator();
            while(it.hasNext()){
                oos.writeObject(it.next());
            }
        } catch (IOException io){
            //vmi amivel lekezelem
        }
    }