Possibility for same group to be created multiple times

We have code creating groups on the fly as users login, we've seen a case where a group can get created multiple times with the same name.
A guess on a fix is that there could be a synchronized block in the createGroup code to make sure there isn't a race condition between get-create from the database there. There should probably be a unique constraint on group name in the database as well.

Klas Lindfors
Stockholm University