Python tools to manipulate JARs ?

[Andy Dingley]

I run build processes for a Java shop using Python (and some Ant).

Would anyone care to suggest favoured tools for manipulating the
innards of JARs? Or do I just treat them as plain zipfiles and get
stuck right in there?

Mainly I'm trying to query lists of classes and their embedded
versions and do some library dependency reporting. Performance speed
is starting to be an issue, as there's 1500+ classes in this bucket
and it's an interactive query.

Thanks for any suggestions