using J-classes or extend them ?

Hi

As I'm teaching myself the art of GUI using swing , I usually find two manners for using the swing J componnets: I'm new in Java , so I'm not quite realize the differnences between them - can you help me?


1: just use them, make Jframe and JPanel and Jbuttons and add them ext..

2: extend - I saw in some example that instead of create JPanel , a new calss is created by extending the JPAnel class: (for example)

Code:

---

class ButtonPanel extends JPanel

---

3: implement them ( mainly for actionlistener) - for example

Code:

---

class Lnr_3 implements ActionListener {                       
                        Lnr_3 ()
                        {       
                                //constructor                        }
                                       
                        public void actionPerformed(ActionEvent e) {
// the method itself....
                                                        }// end of actionPerf

                }

---

These classes are no different from other classes, and you use them in the way that works best in the situation at hand.

Having said that, I sense that with OOP programming in general, there has been a trend recently to avoid extending by inheritance and instead trying to extend more by composition, and this trend can be seen with Swing code as well.