We are seeing the following errors in our logs
Uncaught Throwable java.util.ConcurrentModificationException and
javax.jcr.RepositoryException: this session has been closed.
One possible cause of this issue is a shared session used by some of the CQ5 libraries. A "shared session" is basically a single JCR session that is used concurrently by multiple threads.
In CQ5.3 there are a few known shared sessions that have been identified and resolved with patches. These patches have been delivered as the following hotfixes and feature packs:
- Hotfix http://localhost:4502/libs/cq/packaging/content/packageshare.html/packageshare/packages/internal/day/cq530/hotfix/cq-5.3.0-hotfix-29516.html
This patch resolves an issue where replication can fail due to shared session usage.
- Hotfix http://localhost:4502/libs/cq/packaging/content/packageshare.html/packageshare/packages/internal/day/cq530/hotfix/cq-5.3.0-hotfix-30008.html
This patch resolves a shared session issue in the CQ5 security libraries.
- Feature Pack http://localhost:4502/libs/cq/packaging/content/packageshare.html/packageshare/packages/internal/day/cq530/feature/cq-5.3.0-featurepack-29433.html
This patch resolves a shared session issue in the CQ5 workflow libraries.