This is a classic problem that I see over and over again. The finalize() method is nice, but you shouldn't use it as your only tear-down method, especially when cleaning up files. Hopefully this posting will turn up when someone is trying to figure this out.
This is reference page for the Java course I taught for PWC. We'll put links and notes here for things that we talk about in the course. You can also leave comments for anything that I miss.
I like that Java can tell you what platform it is running on, but often I forget what strings to expect from the os.name and os.arch System properties. Google revealed a nice list.
If your command line parameters aren't working in Ant, here is a possible fix. Blarg!