Hi,
I just installed the GPIO binding using the apt-get method.
I edited etc/default/openhab and set following:
USER_AND_GROUP=root:root
JAVA_ARGS=-Djna.boot.library.path=/usr/lib/jni
as the documentation says.
After this, openhab refused to start with the following error :
openhab.sh[20155]: Invalid Configuration LocationThe configuration area at ‘/var/lib/openhab/workspace’ is not writable.
(I use systemctl for starting openhab)
To fix it, I had to edit /usr/lib/systemd/system/openhab.service and set user and group to root.
I am not sure if its correct, if it is, the doc should probably be updated with it.