Re: Summary of the idéas.
> I'd have thought program-specific jars are by definition, not shared,
> and therefore do not belong on /usr/share?
False. In java there's precious little difference between programs and
binaries; they're often both jar files where the program simply has a
class hiding somewhere with a main() method.
As an example, jython is presented as a single jar (jython.jar). This
contains a class with main() that is called by /usr/bin/jython. However,
the same jar - the same set of classes - can be used as a library by
programs that want to have embedded scripting (if you have
jython-doc installed you can see the API).