To begin your Swing program, lay out the program using stepwise refinement, draw a picture of your GUI design, and list the components you want to use. You'll then need to create an instance of a window or frame object – the preferable way to do so at this point is to extend JFrame and add elements for your own class. You will also need to include the ability for your program to know when the user clicks the close box on the frame, to end the program. For the present, use the method setDefaultCloseOperation(), inherited from JFrame, with the JFrame final variables:

   class SomeFrame extends JFrame
   {
	 public SomeFrame()
	 {
	      // set the title, size, location, etc.
              // add more stuff here...
              setDefaultCloseOperation( EXIT_ON_CLOSE );
              setVisible(true);
         }
   }

Our suggestion is to start small – begin by only writing the constructor to set the size and location of the frame object, and to make the program end. Then write main, and create an instance of the frame. Compile and run the program, to make sure the frame will show up on screen, and that it will close when the user clicks the close box. Once you've got that structure down, you can go back to the line above that says "add more stuff..." and start to do so. If you add elements one at a time, then compile and check them, you can find/figure out errors much more easily than if you write large blocks of code and don't know where the problem might lie. Get your GUI created and working, remember to add the listener(s) you need for buttons, etc., and afterwards write the methods you need to use to respond to the listener(s) and to process any input or print results.