can anyone help ? i just want to construct the frame and see the menu but the menu dont show.

Code:
import java.awt.*;
import javax.swing.*;

public class MainFrame extends JFrame {
public MainFrame() {
super("******* !"); // calls constructor method of jframe with title as argument
setSize(900, 500);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);

JMenu mn1 = new JMenu("Game");  //create a jmenu item object

JMenuItem mn1New = new JMenuItem("New Game");
JMenuItem mn1Quit = new JMenuItem("Quit Game");

mn1.add(mn1New);
mn1.add(mn1Quit);

JMenu mn2 = new JMenu("Theme");  //jmenu container holds jMenuItem components 

JRadioButtonMenuItem mn2Girl =new JRadioButtonMenuItem("Girl",true);
JRadioButtonMenuItem mn2Van =new JRadioButtonMenuItem("Van");
JRadioButtonMenuItem mn2Sub =new JRadioButtonMenuItem("Subway");

mn2.add(mn2Girl);
mn2.add(mn2Van);
mn2.add(mn2Sub);

JMenuBar mnb = new JMenuBar();

mnb.add(mn1);
mnb.add(mn2);

setJMenuBar(mnb);
}

public static void main(String[] args) {
MainFrame gameWin = new MainFrame();

}
}