Dear groupmembers,
Due to certain reasons, i have to (or thougth that i have to) find out if an entity is already stored in the db.
If true, i will merge the entity, if not, other things shall happen.
My entity has a list of other objects, annotaned (one directional):
@OneToMany
private List<Sample> samples;



I was very surprised to find the following hibernate (4.1.3) behaviour:

EntityManager em = emf.createEntityManager();

try{
EntityTransaction tx = em.getTransaction();
tx.begin();
//test that data are ok
for (ISample s: ss.getSamples()){
debug(s.getSampleName());
//here my entity ss has various samples in the list
}
SubSet ss2=em.find(SubSet.class,ss);
//SubSet ss2=(SubSet) ((Session)em.getDelegate()).get(SubSet.class,(SubSet)ss); //same is true for pure hibernate
if (ss2==null){
//do something else
}
else{
for (ISample s: ss.getSamples()){
debug(s.getSampleName()); // my samples are GONE !!! The list is empty !
}
}

....
In summary: if i perform a simple find or get action, the object used for this as provider for the ID is affected seriously
So my question is:
how can i test for the existence of an object in the database without side-effects?

Maybe a simple mis-configuration issue (i`m hibernate novice) but i lost too much time on it and did not find anything by google so any explanation is highly appreciated
Thanks,
retep