Swing/AWT/SWT :: Making GUI Application Design Extensible

I have to create a Swing application for which i haved a set of requirements as,

1. there will be two JPanels ,left and right, on the main JFrame , left frame would contain a JTextField and a submit JButton ,user can enter values 1,2,3 ,in the JTextField and presses the JButton

a. if user enters 1, a JTextField will be shown on right JPanel
b. if user enters 2, a JTextField and a JRadioButton will be shown on right JPanel
c. if user enters 3, a JTextField and a JComboBox will be shown on right JPanel

So I have done that but when my boss sees the code behind this application he told me to make it more extensible i.e. if there is going to be an additional requirement for values 4 or 5 or 6 and so on , then i have to make minimal changes in my code or no change in my code and it should work . how this can be done ? is it possible make such software design ?

public class DesktopApp extends JFrame {
private static final long serialVersionUID = 1L;
private static final Logger logger = Logger.getLogger(DesktopApp.class);
private JPanel jp, jp2, mainPanel;
private JLabel jl, jl1, jl2, jl3, jl4, jl5;
private JTextField jText, jText2, jText3, jText4;

[Code] ....

What wrong am i doing here in this code which in not considered to be an extensible design ?