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);

}

}