ESEMPIO 3
class Applet3Listener implements ActionListener {
JTextArea area; JTextField riga;
Applet3Listener(JTextArea ta, JTextField tf){
public void actionPerformed(ActionEvent e){
String azione = e.getActionCommand();
if (azione.equals("Elimina")) testoDaInserire = "";
else testoDaInserire = riga.getText();
int start = area.getSelectionStart();
int end = area.getSelectionEnd();
area.replaceRange(testoDaInserire,start,end);
area.select(start,start);