private static void save() {
        ObjectOutputStream oos = null;
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(FILE);
            oos = new ObjectOutputStream(fos);
            oos.writeObject(instance);
        } catch (Exception ex) {
            System.err.println("Could not save scores: " + ex);
        } finally {
            if (oos != null) {
                try {
                    oos.close();
                } catch (IOException ex) {}
            }
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException ex) {}
            }
        }
    }