Jan Schatteman ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *commented* on HHH-16267 ( https://hibernate.atlassian.net/browse/HHH-16267?atlOrigin=eyJpIjoiMzdmZD... ) Re: ConcurrentModificationException: when initializing lazy one-to-many-collection ( https://hibernate.atlassian.net/browse/HHH-16267?atlOrigin=eyJpIjoiMzdmZD... ) That’s going to be a hard one to debug then … Maybe give us the mapping of the association that caused the problem, and some context around when it happened (what the app was doing) ? Anything that provides more context will help, but again if this is something that even you cannot reproduce, for us it’s even prob. more difficult ( https://hibernate.atlassian.net/browse/HHH-16267#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16267#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100217- sha1:c17c655 )