Hi all I got this error: ConcurrentModificationException this is my case: i have one button with one ActionListener method (buscaNumero) in this "buscaNumero" method, i have to simulate two events more, i means, i have to do this: ActionEvent evt1 = new ActionEvent(new HtmlCommandLink()); gb.toggleSubGroupAction(evt1); gb is a backing bean object and ActionEvent evt2 = new ActionEvent(new HtmlCommandLink()); u.toggleSubGroupAction(evt2); u is ...