I've tried two versions of JBidwatcher: version 2.0.1 which is stated to be stable and 2.1pre4 which is a prereleased development version, both are unusable!!
Version 2.0.1 is broken because the ebay site has been redesigned.
Version 2.1pre4 is able to fetch some information from the ebay site but not all and it's not reliable - sometimes it works sometimes not. Furthermore this version is very buggy, you may for example delete a tab and content which trows an IndexOutOfBoundsException. The search thread can not be interrupted it goes on and on spilling items into the given tab or the current tab afterwards you will find no way to delete them only one by one.
One of the most disappointing things about JBidwatcher is that you won't find any source code on the net. The only archive I found was jbidwatcher-2.0.1.tar.bz2 which does not contain a single line of code. Furthermore Morgan Schweers seems to be the only contributer to this software.
My conclusion is that it is better to stay away from JBidwatcher because a software for online trading should be very mature, reviewed and tested by a team of several developers, testers and users. At the moment it's not impossible that it does any false biddings or it contains any spyware, backdoor or other things considered harmful.