Like most modern graphical user interface systems, the LAF is an event driven program. Most event driven systems have the same general structure, which may be found in one function, as here, or may be hidden in several different functions.
The main program performs initialization, then sits and waits for something interesting to happen. Examples of interesting things are a mouse down, a key press, a disk being inserted, or others. When something interesting happens the system responds to it, then goes back to waiting.
When the user indicates the application is finished, whatever cleaning up is necessary is performed, and the program quits.