When you run the applet, it is displayed in the applet viewer:
And, you can even embed the matissefied applet in a web application and then deploy it and display it in a browser (but I've only got this to work in FireFox):
Not bad, huh. But I wonder if this is useful? Wouldn't this kind of application more commonly be implemented within a JSP page (or servlet)? Still, it's odd that nobody seems to have mentioned this possibility.
If you want to give it a go yourself, take a look at the new and updated NetBeans IDE 5.0 Applet Tutorial.