Jacob was developed by Vojko (a good friend of mine who pass away several years ago) and other co-workers. Vojko was also a member of [url=http://colos.org/]CoLoS[/url] group.
The Jacob web page is located at http://www.phy.ntnu.edu.tw/demolab/CoLoS/JaCob/
You will find that Jacob need jacob.jar (from the source of the html page)
So you should be able to download it from http://www.phy.ntnu.edu.tw/demolab/CoLoS/JaCob/jacob.jar