JPanel - Atualizar conteúdo

TaskPaneItem item = new TaskPaneItem("alpineclients.userinterface.JPanelAddClient");
        item.setText("Cadastrar novo cliente");
        item.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent arg0) {
                jPanel.removeAll();
                jPanel.add(((TaskPaneItem)arg0.getSource()).getPanel());
            }
        });