How to migrate JOSM settings between Macs

I just got a new iMac and want to migrate all my settings to the new system. I copied the josm folder i my library folder, but that doesn’t seem to be all necessary. But when I also copy the josm folder in the preferences folder of my user folder, josm (on the new computer) won’t start at all anymore.
What do I have to do, so my instance of JOSM looks and behaves the same as it does on my old Mac?

I don’t see JOSM stuff in the typical unix fashion at ~/.josm but I do see a whole directory structure at ~/Library/JOSM/ that looks like it contains all the plug-ins in use and other stuff. I can’t say that it is all your JOSM settings but it might be.