Java tutorial
import java.awt.Graphics; import javax.swing.JComponent; import javax.swing.JFrame; class MyCanvas extends JComponent { public void paint(Graphics g) { g.drawOval(10, 10, 200, 200); } } public class DrawOval { public static void main(String[] a) { JFrame window = new JFrame(); window.setBounds(30, 30, 300, 300); window.getContentPane().add(new MyCanvas()); window.setVisible(true); } }