Multiple JOSM installation/profile

It seems like even if users install multiple JOSM into their machine, different JOSM installation would still share same default path that store application and user data. If the user is involved in multiple different projects that can use JOSM for instance if the user is editing OpenHistoricalMap on top of editing OpenStreetMap, it would be desirable to have different profiles so that it would not be needed to switch between different profiles every time the user switch between different project. How to achieve this effect for the JOSM program?

These paths can be set using system properties specified from the command line.
See the JOSM Preferences documentation.