Java tutorial
import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.geom.RoundRectangle2D; import javax.swing.JFrame; import javax.swing.JPanel; public class MainClass extends JPanel { public void paint(Graphics g) { Graphics2D g2 = (Graphics2D) g; RoundRectangle2D r = new RoundRectangle2D.Double(10.0, 10.0, 50.0, 50.0, 5.0, 5.0); g2.draw(r); } public static void main(String[] args) { JFrame frame = new JFrame(); frame.getContentPane().add(new MainClass()); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(200, 200); frame.setVisible(true); } }