Part of the reason we are having this conversation is that the installer has NOT screwed up on the thirty or so Windows 7 installations I have built and so there has to be another factor involved even if better minds than mine decide that the best place to address this issue is with the Java installer.
As for hijacking the jar extension, there are several archive and compression utilities that do exactly that and the little utility that fixes this problem was written because of that (according to the author's web page as filtered through my memory). So sh*t happens and I happen to think the biggest problem is that someone thought their archive and compression utility needed to work automagically for jar files on Windows.
As I said before, I'd be willing to bet that if that IS the case then it would pretty much have to be 7zip as whenever I've upgraded it, I've always uninstalled previous versions. Seems to me that one of those could possibly have hijacked the extension. Being that it's the only compression utility I use any more, then that would be it. On the other hand, every single time java updates, it also upinstalls the previous version I believe so it could be some sort of conflict between the two of them.
In other words, who the hell knows? Although I DO find this a pretty interesting discussion, I'd still like to day thanks again for all the help you people have done for me.
