Hey, Two things come to mind, 1. You have to make sure the jar, with the new name, is on the classpath of the project. In eclipse, go to project properties, buildpath, add the jar. I don't know how to do this in iReports, but I think you can 2. That file jasper_extensions, is in the jar jasper-x-x.jar. You can open the jar and view the file with winRaR, modify, and save to the jar. Happy Printing!