Hello,

Following my observations from link I open this ticket as instructed on same topic.

Basically I have 2 Hibernate persistent entities Company, Manager ("has a" relationship).
Manager.resume is annotated with (@Basic(fetch = FetchType.LAZY)). Both entity classes are compile time instrumented by org.hibernate.orm.tooling:hibernate-enhance-maven-plugin.

At runtime during the transactional/Hibernate session scope:

• create new instance Company/Manager
• assemble them (they are still transient)
• try to call session.merge(company). Following this I get the error below.
  The use case can be reproduced with the attached test case.

java.lang.ClassCastException: org.hibernate.bytecode.enhance.spi.LazyPropertyInitializer$1 cannot be cast to [B
at org.hibernate.type.descriptor.java.PrimitiveByteArrayTypeDescriptor.areEqual(PrimitiveByteArrayTypeDescriptor.java:26)
at org.hibernate.type.AbstractStandardBasicType.isEqual(AbstractStandardBasicType.java:195)
at org.hibernate.type.AbstractStandardBasicType.getReplacement(AbstractStandardBasicType.java:75)
at org.hibernate.type.AbstractStandardBasicType.replace(AbstractStandardBasicType.java:361)
at org.hibernate.type.TypeHelper.replace(TypeHelper.java:211)
at org.hibernate.event.internal.DefaultMergeEventListener.copyValues(DefaultMergeEventListener.java:430)
at org.hibernate.event.internal.DefaultMergeEventListener.entityIsTransient(DefaultMergeEventListener.java:232)
at org.hibernate.event.internal.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:172)
at org.hibernate.internal.SessionImpl.fireMerge(SessionImpl.java:881)
at org.hibernate.internal.SessionImpl.merge(SessionImpl.java:848)
at org.hibernate.engine.spi.CascadingActions$6.cascade(CascadingActions.java:261)
at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:391)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:316)
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:155)
at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:104)
at org.hibernate.event.internal.AbstractSaveEventListener.cascadeAfterSave(AbstractSaveEventListener.java:445)
at org.hibernate.event.internal.DefaultMergeEventListener.entityIsTransient(DefaultMergeEventListener.java:238)
at org.hibernate.event.internal.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:172)
at org.hibernate.event.internal.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:68)
at org.hibernate.internal.SessionImpl.fireMerge(SessionImpl.java:857)
at org.hibernate.internal.SessionImpl.merge(SessionImpl.java:838)
at org.hibernate.internal.SessionImpl.merge(SessionImpl.java:843)
at org.hibernate.bugs.ORMUnitTestCase.hhh123Test(ORMUnitTestCase.java:88)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.hibernate.testing.junit4.ExtendedFrameworkMethod.invokeExplosively(ExtendedFrameworkMethod.java:45)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.internal.runners.statements.FailOnTimeout$StatementThread.run(FailOnTimeout.java:74)

As I said in the post, by debugging and checking your github fixes for hibernate 4.x on same error:
Maybe a solution would be to modify the following method ? org.hibernate.type.TypeHelper.replace(Object[], Object[], Type[], SharedSessionContractImplementor, Object, Map, ForeignKeyDirection))

by adding a condition like you did when fixing the other

Code:
else if ( target[i] == LazyPropertyInitializer.UNFETCHED_PROPERTY ) {
if ( types[i].isMutable() )

else

}

just as you did with the other one: org.hibernate.type.TypeHelper.replace(Object[], Object[], Type[], SharedSessionContractImplementor, Object, Map) in pull 891 https://github.com/hibernate/hibernate-orm/pull/891/files

I think this method is called for MyEntity properties (org.hibernate.type.TypeHelper.replace(Object[], Object[], Type[], SharedSessionContractImplementor, Object, Map, ForeignKeyDirection))) because I am persisting MyEntity indirectly through a parent entity MyContainerEntity (one-to-one relation, MyEntity being the owning side).

So the particularity of this case is that that a child entity fails to get merged through a parent entity. The child entity is compile time instrumented and has a LAZY Basic attribute/property.

Thanks in advance for looking