Do you have to extend JApplet in your main class?
I'm just wondering if the class that extends JApplet has to be your main class.
No, it doesn't have to ... in either case.
An application that is designed to run as an applet does not need a static void main(String[])
method. You can include one if it makes sense for your application, and if you do, the method does not need to be a method of your JApplet
subclass. But it may be, if you want.
So what you are proposing to do (with two classes) can be made to work, and (IMO) seems like a good approach.