'void' type not allowed here - listener to a parameter

Question

Why you can't add a listener to a object which is a parameter?

panelThird.add(new JTextField( "Write here !" ).addActionListener(
        new ActionListener(){
            public void actionPerformed(ActionEvent e) {
                dlm.addElement(e.getActionCommand());
            }
        }), 
        BorderLayout.SOUTH);

Answer 1

addActionListener has a return type of void - so you can't write:

panelThird.add(new JTextField(...).addActionListener(...));

Instead, you need:

JTextField field = new JTextField(...);
field.addActionListener(...);
panelThird.add(field);