public void shutdown() {
        if (this.timer != null) {
            this.timer.stop();
            this.readThread.interrupt();
            try {
                this.readThread.join(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        this.timer = null;
        this.backgroundImage = null;
        this.skin = null;
        this.btnAccPreview.shutdown();
        this.btnLocalePreview.shutdown();
        this.shutdownPreview.shutdown();
        this.brdPreview.shutdown();
        this.secPreview.shutdown();
        this.userlistPreview.shutdown();
        this.usertilePreview.shutdown();
        this.btnAccPreview = null;
        this.btnLocalePreview = null;
        this.shutdownPreview = null;
        this.brdPreview = null;
        this.secPreview = null;
        this.userlistPreview = null;
        this.usertilePreview = null;

        Runtime.getRuntime().gc();
    }