import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
public class Main {
public static void main(String args[]) {
JButton jbtnA = new JButton("w3cschool.cn");
JFrame jfrm = new JFrame();
jfrm.setSize(300, 300);
jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jfrm.getRootPane().setDefaultButton(jbtnA);
jbtnA.setMnemonic(KeyEvent.VK_A);
jbtnA.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
System.out.println("Alpha pressed. Beta is enabled.");
jbtnA.setEnabled(!jbtnA.isEnabled());
}
});
jfrm.add(jbtnA);
jfrm.setVisible(true);
}
}