Alt key causes NullPointerException

Question

I am getting a NullPointerException in a Swing based GUI application when I use the 'Alt' key with JButtons containings mnemonics.
There was an earlier topic of the same issue traced to either setLookAndFeel() or using a Frame instead of JFrame. I am using a JFrame and not using setLookAndFeel() is not under consideration.
Anybody have any ideas?

Answer 1

Mine too! I'm not using setLookAndFeel(0 and am using JFrame! Here's my codeimport java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Test extends JFrame {
  public Test() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container content = getContentPane();
    JButton jb = new JButton("Hello, McFly!");
    jb.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent ae) {
        if ((ae.getModifiers()&ae.ALT_MASK)!=0) throw new NullPointerException();
    jb.setMnemonic('b');
    content.add(jb, BorderLayout.SOUTH);
    setSize(300, 275);
    setVisible(true);
  public static void main(String args[]) { new Test(); }
}Any ideas?