For anyone that stumbles across this, the answer was in here:
In Openfire installation, under lib directory, there's a config file named
just modify this and override default one.
If you need a log4j tutorial, check out at: https://www.mkyong.com/logging/log4j-xml-example
In you case you can:
- redirect your own classes in another custom file
- redirect all debug in another file and keep your custom class in default debug log so it will be viable by Openfire webinterface