void (String[] args) { @SuppressWarnings("HardCodedStringLiteral") JFrame test = new JFrame("Config test"); test.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); final JPanel comp = new JPanel(new BorderLayout()); comp.add(new ConfigUI(new Config()), BorderLayout.CENTER); test.getContentPane().add(comp); test.setSize(450, 450); test.setVisible(true); }