How can I figure out which .jar files my report is currently attempting to use?

I am editing a report in iReport that someone else has previously made and I am wondering as to how i could figure out which .jar files they were referencing to compile the report. Is there a way to do this in iReport or am I just going to have to ask? Also- if I can figure it out where do I find a collection of .jar files to download and use?

Thanks for any help!

-Colt