Remove the directory /usr/openhab2 and re-create it from scratch, as with a completely new concentrator

[Reason] Some file is corrupted and we don't know what

1. Before you delete bbb:/usr/openhab2 , you might first want to save a certain file
   [IP Address of concentrator] 10.8.0.xx  (where XX is the PNPC no)
   pnpcXX.pnpscada.net (where XX in the PNPC no)
   [File to save] /usr/openhab2/MASTER/userdata/uuid
   the uuid in there is something like this: 40f02342-309c-4445-aee9-3c70a19b5ad7
   this is the unique identifier of the concentrator (so we might want to keep note of that)

2. you want to stop java completely
   . Place a # before Java in start.sh
   . then you want to delete and copy across: addons conf runtime userdata (those 4 directories)
   . and then you want to put the uuid of 40f02342-309c-4445-aee9-3c70a19b5ad7 back into /usr/openhab2/MASTER/userdata/uuid
   . and then take out the # in start.sh again