This looked interesting and I tried to download it and play with it, just to see what it does. Unfortunately, the download totally messed up my computer - and I had to uninstall and reinstall the TWS, java, and a couple of other things. The problem has not been resolved yet. Maybe it's my software setup, or the fact that this free software is not properly developed and/or maintained. However, I now have enough evidence to say to other prospective users "be careful."
??? I would love to hear more details on the difficulties you experienced. But IBTrader is unlikely to be the culprit for your problems. Downloading and running a jar file certainly would not harm your Java and TWS and other installs. At this stage IBTrader does not even persists information on your local disk ...
After communicating with a couple of helpful people and studying the many relevant posts on IB's bulletin board, I decided to delete all java and TWS material from my computer (took a while) and do a clean re-install of those two platforms. It worked. I can't say that something's wrong with IBTrader, but the IB/Java/videocards/key-add-ons combination is so sensitive and temperamental that I've learned from experience (this one is the latest) to leave my trading computer alone and experiment with new stuff in my development computer. Oh well, live and learn.