public class Driver {
    public static void main(String [] args) {
        JFrame myFrame = new JFrame ("Plain window");
        JButton myButton =new JButton("On");
        myFrame.add(myButton);
        myFrame.setBounds(100,100,300,200);
        myFrame.setVisible(true);
       
    }
}

public class MyButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
    }
}