public class FeatureListBox extends ListBox
{
    public FeatureListBox()
    {
    }
    public FeatureListBox(boolean isMultipleSelect)
    {
        super(isMultipleSelect);
    }
    public FeatureListBox(Element element)
    {
        super(element);
    }
}

FeatureListBox listBox = new FeatureListBox();
listBox.addChangeHandler(new ChangeHandler()
{
    public void onChange(ChangeEvent event)
    {
        // Do something here...
    }
});