I have been communicating with the author and the situation is like this; MacOS9 will be the only major OS without Swing (OSX has it). There is an attempt from an Italian university to create an alternative to it, though, but the result lies in the future. So, it's either to get it now or to wait until you move to X, if you want to use this app or any other which needs Swing. (This is the first I've come across, though)