Guillaume Toison ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=70121%3... ) *created* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiYzM4NWQxMTQ0... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-16952?atlOrigin=eyJpIjoiYzM4NW... ) HHH-16952 ( https://hibernate.atlassian.net/browse/HHH-16952?atlOrigin=eyJpIjoiYzM4NW... ) Bytecode enhancement now requires embedded component to be @Embeddable ( https://hibernate.atlassian.net/browse/HHH-16952?atlOrigin=eyJpIjoiYzM4NW... ) Issue Type: Bug Affects Versions: 6.2.6 Assignee: Unassigned Components: hibernate-core, hibernate-enhance-maven-plugin Created: 18/Jul/2023 00:04 AM Priority: Minor Reporter: Guillaume Toison ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=70121%3... ) When upgrading an application from Hibernate 5.6 to 6.2 I ran into an issue where the class corresponding to an @Embedded property was not annotated with @Embeddable I am also using the enhance maven plugin: <plugin> <groupId> org.hibernate.orm.tooling </groupId> <artifactId> hibernate-enhance-maven-plugin </artifactId> <version> ${hibernate.version} </version> <executions> <execution> <configuration> <failOnError> true </failOnError> <enableLazyInitialization> false </enableLazyInitialization> <enableDirtyTracking> true </enableDirtyTracking> <enableAssociationManagement> false </enableAssociationManagement> <enableExtendedEnhancement> false </enableExtendedEnhancement> </configuration> <goals> <goal> enhance </goal> </goals> </execution> </executions> </plugin> With Hibernate 6 this fails at runtime when trying to call the property setter: java.lang.ClassCastException: Object of type 'class abc.MyComponent' can't be cast to CompositeTracker at org.hibernate.engine.internal.ManagedTypeHelper.asCompositeTracker(ManagedTypeHelper.java:337) at abc.MyEntity.$$_hibernate_write_myEmbeddedProperty(MyEntity.java) Unless I’m mistaken it is indeed requirred by the JPA spec that the class is annotated with @Embeddable so it is user error and it is fair enough that it fails. However the error message (and the cause of the problem) was not so obvious to me, I found solution from someone who ran into a similar problem: https://github.com/quarkusio/quarkus/issues/34603 Maybe this should fail at build time, when running the bytecode enhancement? Or maybe the error message could mention @Embeddable as a possible cause for the error? I’ve tried making a unit test reproducing the problem but could not, so maybe I misunderstood the issue. ( https://hibernate.atlassian.net/browse/HHH-16952#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16952#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#100232- sha1:4a3b42c )