Description
Some best practice.
Use unique and meaningful names for your Keys (like your package-Name) e.g.: "com/mycompany/myapp/myKeyForNumberFormatting"
Or at least your AppName: e.g.: "MyPowerApp/myKeyForTheFormularToSolvingEveryThing"
Applikation specific configurations like third part Server adresses.
Everything who should be differ from Development-, Testing- and Production-System, but changes never (or at least rarely) after deploying.
Webapp-User specific configurations like personal preferences have nothing to do with settings4j !