Hi Friend,

It seems that you haven't use ItemSelectable class. You can use addActionListener() on Combo Box in the following way:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Example1 {

public static void main(final String args[]) {
final String st[] = { "A", "B", "C"};
JFrame frame = new JFrame();
JComboBox combo = new JComboBox(st);
frame.add(combo);
ActionListener actionListener = new ActionListener() {
public void actionPerformed(ActionEvent e) {
ItemSelectable is = (ItemSelectable)e.getSource();
System.out.println("You have selected: " + selectedString(is));
}
};
combo.addActionListener(actionListener);
frame.pack();
frame.setVisible(true);

}
static private String selectedString(ItemSelectable is) {
Object selected[] = is.getSelectedObjects();
return ((selected.length == 0) ? "null" : (String)selected[0]);
}
}

Thanks