Ronny Bräunlich ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=62f2786... ) *commented* on HHH-16662 ( https://hibernate.atlassian.net/browse/HHH-16662?atlOrigin=eyJpIjoiZmE4MD... ) Re: Postgres Mapping of JSON column to Map<> causes class cast exception ( https://hibernate.atlassian.net/browse/HHH-16662?atlOrigin=eyJpIjoiZmE4MD... ) I didn’t want to create a test using Spring Data JPA, therefore it looks slightly different from the description but it should showcase the problem: hibernate-test-case-templates/JPAUnitTestCase.java at main · rbraeunlich/hibernate-test-case-templates · GitHub ( https://github.com/rbraeunlich/hibernate-test-case-templates/blob/main/or... ) In the test, the DynamicInstantiationResultImpl states that Map and Map aren’t compatible. ( https://hibernate.atlassian.net/browse/HHH-16662#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16662#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#100225- sha1:bbd69a1 )