These files are containing the class ant.util.FileUtils

development-time tool for generating additional artifacits

IzPack is an installers generator for the Java platform. It produces lightweight installers that can be run on any operating system where a Java virtual machine is available. Depending on the operating system, it can be launched by a double-click or a simple 'java -jar installer.jar' on a shell. The most common use is to distribute applications for the Java platform, but you can also use it for other kinds of projects. The main benefit of IzPack is that it provides a clean and unique way of distributing a project to users using different operating systems.