unable to access variables

[jinnejeevansai]

I was creating a swing applet if i make a seperate class of action listener i was unable to access extended class variables.Can someone explain my mistake and modify the code without merging two classes.

import javax.swing.*;
import java.awt.*;
public class Clock extends JApplet{
JFrame frame;
JPanel panel;
JButton button;
public void init(){
frame = new JFrame();
frame.setSize(700,600);
panel = new JPanel();
button = new JButton();
button.addActionListener(new listener());     //if i use seperate class listener instead of writing code here itself and try to access the variables of this class null pointer exception occurs
button.setText("aaaaaaa");
panel.add(button);
frame.add(panel);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}

import java.awt.event.*;
class listener extends Clock implements ActionListener {
public void actionPerformed(ActionEvent e){
button.setText("bbbbbbbbbbb");
}
}

[rajujrk]

Hi jinnejeevansai,

Make that variable as protected, default Access Modifier is "default" and it will be accessed within the package. When you extending the class and trying to access the class variable, use protected as always.

Thanks
Rajkumar