org.hibernate.PersistentObjectException: detached entity passed to persist:

[Unnikrishnan Rem]

Sorry to edit post completely..

I got this exception when i submit a page second time in the same instance.
try the folowing if you get the same...

in your session bean
Check whether the entity instance is null
if (entity== null) {
em.persist(entity);// then use persist()
}
else{
entity= new Entity();
em.merge(entity);//other wise use merge()
}

[ntumba lobo]

In your code don't you mean ?

if (entity!= null) {
em.persist(entity);// then use persist()
}
else{
entity= new Entity();
em.merge(entity);//other wise use merge()
}

Because in your current version if entity is null you basically call em.persist(null) !

[Unnikrishnan Rem]

The EntityManager persist(Object entity) API is used to mark a new instance for insert into the Database

Usage of the EntityManager AP

For the bean's first instance it does persist and for subsequent it should merge as already the identifier is in persistent state