Is there are way to patch jar files?

Question

Suppose I sent a large jar or war file to someone. Could I later just change one small section and send that to him? Suppose I just changed one class file. I recompiled t

Answer 1

If you have your old and new jar file, you can create an xdelta of both and send only the delta file to your client, which should be much smaller than the whole jar file, if you changed only one class of many. This should work for signed jars, too, but requires that both sender and receiver have the xdelta program (or be able to install it).

And of course, you have to create the new jar first (but this can be done by the methods already mentioned by the other answers).