Some time ago I watched the presentation about Thermo. You can read Thermo description or you can jump start to the presentation.
Well, Thermo is a tool not for Java, this is certain, but is built with Java and Eclipse. When you first see you will doubt, but it really is built on Eclipse. Anyway, IBM does a good job of changing Eclipse not-so-attractive appearance in its Lotus Symphony office suite and Lotus Notes app, which, I dare to say, share some good amount of source code.
After watching presentation I think some designer will certainly find Thermo useful ;). I am eagerly waiting for new designer tool from Sun.