It might save some heart attacks if, along with the instructions for how to clear a cache, it is pointed out that one may need to restore file ownership with:
sudo openhab-cli reset-ownership
I had cleared my cache, and then karaf / openhab wouldn’t restart, with logs stating “could not launch framework” and couldn’t initialize storage, etc.
After running:
sudo openhab-cli reset-ownership
Everything was working again.
Anyway, Putting this here for someone else who runs into the same surprise.