public static void shutdown() {
        Settings.saveProperties(Constants.SETTINGS_PATH);

        if (model != null) {
            model.shutdown();
            model = null;
        }

        if (exct != null) {
            exct.shutdown();
            exct = null;
        }

        if (chooser != null) {
            chooser.dispose();
            chooser = null;
        }

        if (editor != null) {
            editor.dispose();
            editor = null;
        }

        SystemInformation.releaseJVMLock();
    }