Indeed, the way Swing is applied in Netbeans and the Netbeans platform is quite impressive. Its the one Java application I know that “just works” GUI-wise on all popular platforms (and as a result apps built with the Netbeans platform share the same sensation). And it probably required plenty of blood, sweat, tears and many hacks to get it to that point I’ll bet Heck, it spawned a whole new LayoutManager in Java 6.
Not exactly lightweight material though, the initialization phase of a simple hello world thing can already take seconds. Such things are exactly the kind of cannon fodder (War! Never been so much fun!) that Java haters abuse Power features such as the fact that you can hot-swap GUI changes directly into a running instance (god I love Java) is conveniently overlooked.