[Java]JPanel pas de sorti

package hacktrack.picturedisplay;

import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Panneau extends JPanel {

	public Panneau() {
		super();
		setPreferredSize(new Dimension(200, 200));
	}

	@Override
	public void paintComponent(Graphics g) {
		System.out.println("Je suis exécutée!!!");
		g.fillOval(20, 20, 75, 75);
	}

	public static void main(String[] args) {
		Panneau pan = new Panneau();
		JFrame frame = new JFrame("Test panneau");
		frame.getContentPane().add(pan);
		frame.pack();
		frame.setVisible(true);
	}
}