The user interface library Qt is licensed under LGPL

There's great news: Qt will be free starting in March 2009, finally. Qt is a cross platform GUI development library. It's a library for GUI development using C++ and Java (which I was not aware of until now). The Java integration is done via JNI. Check this out, there are some Webstart based demos available. I could not get it running on my Mac OS X, unfortunately. But it's tested on Windows and Linux only, anyway.