[Building Sakai] Runaway thread on sakai worker.

[Matthew Buckett]

We recently had a sakai worker develop a runaway thread which appeared
to be repeatedly downloading the single institutional iCal calendar.
>From the log message it looks like it way the cache cleaner:

org.sakaiproject.calendar.impl.BaseExternalCalendarSubscriptionService.SubscriptionCacheMap.run()

Sadly the node get restarted before we noticed this so we didn't
manage to get a heap dump or thread dump. Has anyone else seen this on
2.8.x?

BTW: https://jira.sakaiproject.org/browse/SAK-23162

-- 
  Matthew Buckett, VLE Developer, IT Services, University of Oxford