Problem with actionperformed callback

I tried to create function, what shows textdialog, when client press the buton, but the problem is that i have defined frame under public static void main and in ActionPerformed callback first parameter "frame" is undefined. How could i fix this?

import java.awt.*;































































import java.awt.event.*;































































import java.applet.Applet;































































import javax.swing.*;

public class Vestlus extends Applet implements ActionListener {































































TextField tf = new TextField("");































































Button nupp = new Button(" Sisesta ");

public Vestlus()































































{































































add(tf);































































add(nupp);































































nupp.addActionListener(this);

}































































public void actionPerformed(ActionEvent e)































































{































































if(e.getSource() == nupp)































































{































































JOptionPane.showMessageDialog(frame,"Hoiatus","Vää rtused ei klapi!", JOptionPane.INFORMATION_MESSAGE);

}































































}































































public static void main(String args[])































































{

JFrame frame = new JFrame("Project LA");































































frame.add(new Vestlus());































































frame.setSize(300,200);































































frame.setVisible(true);































































frame.setDefaultCloseOperation(1);

}

}