# Error while persisting an object in Hibernate 6
**URL:** https://discourse.hibernate.org/t/error-while-persisting-an-object-in-hibernate-6/10077
**Category:** Hibernate ORM
**Created:** [August 6, 2024, 6:10am UTC](https://discourse.hibernate.org/t/error-while-persisting-an-object-in-hibernate-6/10077 "2024-08-06T06:10:04Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Kaushik\_LV](https://discourse.hibernate.org/u/Kaushik_LV)
#### Post date: [August 6, 2024, 6:10am UTC](https://discourse.hibernate.org/t/error-while-persisting-an-object-in-hibernate-6/10077/1 "2024-08-06T06:10:04Z")
Hi,
We are trying to migrate to Hibernate 6.5 and as part of this we have changed the implementation from using Sessions to EntityManagers.
Previously while inserting a record we were using the Session class’ save method as follows -
```auto
session.save(entityName, object);
```
Where object was an implementation of HibernateProxy. It was working fine.
Now, in Hibernate 6 we are using EntityManager’s persist method to accomplish the same task as follows -
```auto
entityManager.persist(object);
```
And here as well the type of object is an implementation of HibernateProxy itself
But we are seeing this exception -
```auto
org.hibernate.HibernateException: Could not determine type of dynamic map entity
at org.hibernate.metamodel.internal.EntityInstantiatorDynamicMap.extractEmbeddedEntityName(EntityInstantiatorDynamicMap.java:72)
at org.hibernate.metamodel.internal.EntityInstantiatorDynamicMap.lambda$static$0(EntityInstantiatorDynamicMap.java:59)
at org.hibernate.internal.CoordinatingEntityNameResolver.resolveEntityName(CoordinatingEntityNameResolver.java:35)
at org.hibernate.internal.SessionImpl.guessEntityName(SessionImpl.java:1805)
at org.hibernate.internal.SessionImpl.bestGuessEntityName(SessionImpl.java:1756)
at org.hibernate.event.internal.DefaultPersistEventListener.entityName(DefaultPersistEventListener.java:142)
at org.hibernate.event.internal.DefaultPersistEventListener.persist(DefaultPersistEventListener.java:84)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:77)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:54)
at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:127)
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:757)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:741)
```
Is there any change in behaviour w.r.t saving / persisting the object in Hibernate 6?
---
### Author:  [@beikov](https://discourse.hibernate.org/u/beikov)
#### Post date: [August 6, 2024, 2:31pm UTC](https://discourse.hibernate.org/t/error-while-persisting-an-object-in-hibernate-6/10077/2 "2024-08-06T14:31:08Z")
Using `persist` directly also wouldn’t have worked in previous Hibernate ORM versions. You will have to add a custom `EntityNameResolver` via `org.hibernate.cfg.Configuration#addEntityNameResolver` or implement a [custom `org.hibernate.Interceptor`](https://docs.jboss.org/hibernate/orm/6.5/userguide/html_single/Hibernate_User_Guide.html#events) to help Hibernate resolve the entity name from an object via `Interceptor#getEntityName`.
---
### Author:  [@Kaushik\_LV](https://discourse.hibernate.org/u/Kaushik_LV)
#### Post date: [August 12, 2024, 6:21am UTC](https://discourse.hibernate.org/t/error-while-persisting-an-object-in-hibernate-6/10077/3 "2024-08-12T06:21:37Z")
Hi @beikov
I have tried using the custom `EntityNameResolver` via `org.hibernate.cfg.Configuration#addEntityNameResolver` method.
Here is what I have done exactly -
Created this class CustomEntityResolver -
```auto
public class CustomEntityNameResolver implements EntityNameResolver {
@Override
public String resolveEntityName(Object entity) {
if(entity instanceof CustomHibernateProxy)
return ((CustomHibernateProxy) entity).getEntityName();
return null;
}
public boolean equals(Object obj) {
return getClass().equals( obj.getClass() );
}
public int hashCode() {
return getClass().hashCode();
}
}
```
I have added this Resolver to my configuration before creating the EntityManagerFactory -
```auto
configuration.addEntityNameResolver(new HibernateEntityNameResolver());
```
I still see the same error right now.
```auto
org.hibernate.HibernateException: Could not determine type of dynamic map entity
```
Is there anything else I need to add before calling the `persist` method using the entityManager ?
---
### Author:  [@beikov](https://discourse.hibernate.org/u/beikov)
#### Post date: [August 13, 2024, 12:06pm UTC](https://discourse.hibernate.org/t/error-while-persisting-an-object-in-hibernate-6/10077/4 "2024-08-13T12:06:59Z")
Please try to create a reproducer with our [test case template](https://github.com/hibernate/hibernate-test-case-templates/blob/master/orm/hibernate-orm-6/src/test/java/org/hibernate/bugs/JPAUnitTestCase.java) and if you are able to reproduce the issue, create a bug ticket in our [issue tracker](https://hibernate.atlassian.net) and attach that reproducer.
---
### Author:  [@Kaushik\_LV](https://discourse.hibernate.org/u/Kaushik_LV)
#### Post date: [August 14, 2024, 4:19pm UTC](https://discourse.hibernate.org/t/error-while-persisting-an-object-in-hibernate-6/10077/5 "2024-08-14T16:19:56Z")
Hi @beikov
As requested, I have created a reproducer and raised a bug in your issue tracker. Here is the link to the bug -
[https://hibernate.atlassian.net/browse/HHH-18486](https://hibernate.atlassian.net/browse/HHH-18486)
Hope you have all the information that you need to resolve this issue.