Hi
I am using appfuse framework 1.8.2 and hibernate 3.0.5 I get the exception


org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session:


at org.hibernate.engine.PersistenceContext.checkUniqueness(PersistenceContext.java:586)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performUpdate(DefaultSaveOrUpdateEventListener.java:254)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:214)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:91)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:69)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:468)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:463)
at org.springframework.orm.hibernate3.HibernateTemplate$18.doInHibernate(HibernateTemplate.java:671)
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:356)
at org.springframework.orm.hibernate3.HibernateTemplate.saveOrUpdate(HibernateTemplate.java:668)
at com.nihilent.hrms.dao.hibernate.ResourceAllocationDAOHibernate.saveResourceAllocation(ResourceAllocationDAOHibernate.j
at com.nihilent.hrms.service.impl.ResourceAllocationManagerImpl.saveResourceAllocation(ResourceAllocationManagerImpl.java
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)

I get exception whenever I try to update the previously persisted objects.
First I get a List of POJOs from hibernate store them in session (HttpSession) where user performs the updates and then I get the list and then called getHibernateTemplate().saveOrUpdate(Object obj). for each object on List
POJO and childs that are in list have no equals and hashCode methods implemented.

Thanks

The error means that Hibernate session holds an object of the same class and with the same ID as the object you are trying to saveOrUpdate( or its cascade reachable properties).

Such exception usually happens when session has loaded an object (perhaps indirectly as a property of another object) and now we supply a detached instance of the object to saveOrUpdate method.

As a general comment I would say that using Spring's HibernateTemplate is not good idea. It only seems convenient.
I recommend this approach
http://www.onjava.com/pub/a/onjava/2005 ... tions.html

Good explanation of problem, bad advice.

Follow the FAQ: http://www.hibernate.org/116.html#A8

I did not make myself clear enough. My advice definitely will not cure the problem. It is my general recommendation not to use HinernateTemplate

Thank you. The problem solved. I checked for an object's id before saving and called merge() for objects already persisted.