Google uses bsdiff and Courgette for patching binary files like the Chrome distribution. Do any similar tools exist for patching jar files?

I am updating jar files remotely over a bandwidth-limited connection and would like to minimize the amount of data sent. I do have some control over the client machine to some extent (i.e. I can run scripts locally) and I am guaranteed that the target application will not be running at the time.

I know that I can patch java applications by putting updated class files in the classpath, but I would prefer a cleaner method for doing updates. It would be good if I could start with the target jar file, apply a binary patch, and then wind up with an updated jar file that is identical (bitwise) to the new jar (from which the patch was created).