This article outlines a specific known issue that exists within Liferay Portal 6.1 EE GA3 SP3 and provides a link to follow its resolution.
At the time of release, there is one known issue with Liferay Portal 6.1 EE GA3 SP3. In this version of Liferay, a
ConcurrentModificationException may be experienced when deploying plugins to the portal.
This issue is resolved in the liferay-fixpack-development-6-6130 update. This fix is included with the latest set of fixpacks for the portal.