Catching NoResultException

[leeth]

Hi I have a slsb as a DAO for an entity. I use this slsb i a business component. 
I would like to catch NonUniqueException or NoResultException there because in my opion this is where I wants to determine what action that need to be taken if these exceptions are thrown. But I cannot catch them directly because they are wrapped around a EJBTransactionRolledbackException. I don't quite understand why this is done? Is it a bug or are there some good reason why PersistenceExceptions are caught and throw new EJBTransactionRolledbackExceptions

[blabno]

As to NonUniqueException ... it is thrown when transaction is being commited which does not happen right on em.persist or em.merge but later (i.e. method end). If I want to catch such errors I put em.flush right after em.persist and all exceptions, if any, are thrown there.

[leeth]

I don't understand that. Because I dont commit anything, I'm just quering. I have writen a small pseudo example below to illustratede the situation.
This pseudo example won't work because the dao doesn't throw any of the subtype of PersistenceExceptions but a EJBTransactionRolledbackExceptions.

try{
MyEntity myEntity = dao.findActive();
handleActive(myEntity);

}catch(NoResultException e){
    handleNoActive();
}catch(NonUniqueResultException e){
    log.fatal("more than one active");
    throw new IllegalStateException("Internal error: more than one active record");
}



....
public MyEntity findActive(){
    String queryString = "from entity where endDate is not null";
    Query query = em.createQuery(queryString);
    return query.getSingleResult();
}