public static void main(String[] args) { Canvas canvas = new Canvas(); canvas.setTitle("canvas sample"); canvas.setSize(600, 200); canvas.setLocationRelativeTo(null); canvas.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); CanvasData dd = new CanvasData(300); NewPanel p = new NewPanel(dd); canvas.add(p); canvas.setVisible(true); }