Hi

I am using hibernate with EHCache. I have removed a persisted entity using entityManager.remove(persistedEntity). In a later step, i want to add a new entity with the same natural id as the removed one. Before doing that, i am fetching any entity with that natural id to make sure that there is no such entity in the database :

Criteria c = ((Session) entityManager.getDelegate()).createCriteria(type);
c.add(Restrictions.naturalId().set("name", name));
c.setCacheable(true);
T entity=(T) c.uniqueResult();

I am getting the following exception:


javax.persistence.EntityNotFoundException: Unable to find xyz.application.auth.entity.Group with id 6
at org.hibernate.ejb.Ejb3Configuration$Ejb3EntityNotFoundDelegate.handleEntityNotFound(Ejb3Configuration.java:113)
at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:171)
at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:223)
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:126)
at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:905)
at org.hibernate.impl.SessionImpl.internalLoad(SessionImpl.java:873)
at org.hibernate.type.EntityType.resolveIdentifier(EntityType.java:590)
at org.hibernate.type.ManyToOneType.assemble(ManyToOneType.java:219)
at org.hibernate.cache.StandardQueryCache.get(StandardQueryCache.java:155)
at org.hibernate.loader.Loader.getResultFromQueryCache(Loader.java:2184)
at org.hibernate.loader.Loader.listUsingQueryCache(Loader.java:2147)
at org.hibernate.loader.Loader.list(Loader.java:2117)
at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:118)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1596)
at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:306)
at org.hibernate.impl.CriteriaImpl.uniqueResult(CriteriaImpl.java:328)

it looks as though the removed entity was not evicted from the cache

javax.persistence.EntityNotFoundException: Unable to find xyz.application.auth.entity.Group with id 6

So the EntityNotFoundException is stating that class "Group" with id 6 was not found... I don't know why this is coming back as an exception but you are getting the right result. Could wrap it in a try-catch, until you find a prettier way.

Since this is a natural id, is it possible to place the constraint with DB rather than in hibernate (as you are currently attempting, if it is not already), in which case you simply try to insert the row and check for success?

Actually i am not getting the right result. According the the javadoc of uniqueResult(), the function should return null if the query returns no result. Shouldn't the EntityManager.remove() invalidate the entry in the cache that maps the natural id to the persisted object?