I can't offer anything when it comes to Java, but I just wanted to encourage you to keep going on this project. It overjoys me to see that someone is --FINALLY-- working on a full-featured editor that isn't tied down to a single platform (usually Windows) like Noggit and such is.
As said, I can't offer anything in the ways of Java (the most I know as far as programming is HTML, CSS, and some Objective-C), but if you like I can provide graphics (icons, UI elements, etc.) or work on the interface of the app since I happen to be a designer.
Good luck!