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);

}

}