Thorsten Goetzke ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=6422e66... ) *commented* on HHH-16395 ( https://hibernate.atlassian.net/browse/HHH-16395?atlOrigin=eyJpIjoiZDQ5Zj... ) Re: Initialization of Hibernate Proxies for Abstract Entities can fail ( https://hibernate.atlassian.net/browse/HHH-16395?atlOrigin=eyJpIjoiZDQ5Zj... ) Hello, This issue seems to be caused by a typo in my mapping files. I had an hierary as Tiger extends Cat extends Animal It Should have been: Everything as Joined-Subclass, Animal and Cat using abstract=”true” and Tiger with abstract=”false” . It was: Animal and Tiger had abstract=”true” and Cat had abstract=”false”. Somehow this did not cause any issues in 61.5 and 6.1.6… I guess this is an invalid mapping state which can only be archieved using legacy hibernate mapping files. Best regards, Thorsten ( https://hibernate.atlassian.net/browse/HHH-16395#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16395#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#100219- sha1:6a6077b )