If the state of a CheckboxmenuItem is changed programaticly, ie via a call to setState(), no ItemStateChanged event
is generated or broadcast to the listeners.

sample program CI.java:

/* CI.java -
** tests programatic changes to state of a CheckboxMenuItem to see if a
** registered listener is called.
*/

import java.awt.event.*;
import java.awt.*;

public class CI {
    public static void main(String [] args) {
        Point p;
        Frame frame = new Frame();
        frame.setBounds(100,100,500,500);
        CheckboxMenuItem ci = new CheckboxMenuItem("text", false);
        Menu menu = new Menu("MyMenu");
        MenuBar mb = new MenuBar();
        mb.add(menu);
        menu.add(ci);

        frame.setMenuBar(mb);
        frame.setVisible(true);

        frame.addWindowListener ( new WindowAdapter() {
            public void windowClosing( WindowEvent e ) {
                System.exit(0);
            }
        });

        ci.addItemListener(new LLCI());
        System.out.println("changing CheckboxMenuItem state on and off");
        ci.setState(true);
        ci.setState(false);
    }
}

class LLCI implements ItemListener {
    public void itemStateChanged(ItemEvent e) {
        System.out.println("ItemStateChanged event: "+e);
    }
}