Openfire uses an install4j runtime dependency in its ‘starter’ component.

Openfire includes the binary as part of its source code, and defines the dependency as a system-typed dependency. ~I assume that at the time of the migration from Ant to Maven, this dependency was likely unavailable in a Maven repository, which caused this to be implemented as a work-around.~ The README file in the lib directory describes the rationale for this:

This folder contains an (old) version of the install 4j runtime JAR file. Current ones are available via Maven (see below)
however they do not include some of the classes that are required by org.jivesoftware.openfire.launcher.Uninstaller

The workaround that we have in place now caused the Maven build to generate this warning:

We should update the project and remove the need of keeping a copy of very old libraries.