Christian Beikov ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *commented* on HHH-16225 ( https://hibernate.atlassian.net/browse/HHH-16225?atlOrigin=eyJpIjoiMzhhNW... ) Re: Lazy-loading with parallel stream in a separate thread leads to exception with Hibernate 6 ( https://hibernate.atlassian.net/browse/HHH-16225?atlOrigin=eyJpIjoiMzhhNW... ) This couldn’t have reliably worked before either. You are essentially sharing a Session between fork join threads, which is not allowed. Session is not thread-safe. If you want to improve loading performance, you should rather configure a @BatchSize and initialize in the same thread. ( https://hibernate.atlassian.net/browse/HHH-16225#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16225#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- sha1:58f696e )