simple menu program in java

import java.awt.*;
import java.awt.event.*;
public class menu_ extends Frame implements ActionListener
{
MenuBar mb;
Menu m;
MenuItem m1,m2,m3,m4;
public menu_()
{
mb=new MenuBar();
setMenuBar(mb);
m=new Menu("file");
mb.add(m);
m1= new MenuItem("1");
m2=new MenuItem("2");
m3=new MenuItem("3");
m4=new MenuItem("4");
m.add(m1);
m.add(m2);
m.add(m3);
m.add(m4);
m1.addActionListener(this);
m2.addActionListener(this);
m3.addActionListener(this);
m4.addActionListener(this);
addWindowListener(new c());
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==m1)
System.out.println("m1 is clicked");
else if(e.getSource()==m2)
System.out.println("m2 is clicked");
else if(e.getSource()==m3)
System.out.println("m3 is clicked");
else if(e.getSource()==m4)
System.out.println("m4 is clicked");
}
public static void main(String[] s)
{
menu_ me=new menu_();
me.setVisible(true);
me.setSize(400,400);
}
}
class c extends WindowAdapter
{


    public void windowClosing(WindowEvent e)
    {
        System.exit(0);
    }
   
}