Concurrent modification of notifications possible when storing in a users channel

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.2.X EE, 7.0.0 M3
• Fix Version/s: 7.0.0 M3
• Component/s: Collaboration, Collaboration > API > Notifications
• Labels: None
• Story Points: 4
• Fix Priority: 2
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/22824

There is no reentrant lock on the public method ChannelImpl.storeNotificationEvent()

this would allow concurrent modifications to happen to the internal maps for notificationEvents and unconfirmedNotificationEvents