Build jar files that contain other jar files

[Peter DePasquale]

Since I can't find this on my own, I thought I'd ask.  I need to include two
3rd part jar files in my app's jar file.  I am 99% sure I can't just add the
required supporting jars to my release jar (correct?).  Thus, I need to
unjar my 3rd party jars, and fold their contents into my release jar.  Is
there an ant task for something like this?  Surely this is a common type of
operation....  Thanks.