Saving Using Hibernation / JPA

Question

I have been working with hibernate / JPA on JBoss for several months and have one question that I cannot find an answer or solution to.

It seems that when creating a new beans object, I cannot fulfill the request before I even call EntityManager.persist (entityBean), otherwise I will get the following error:

TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing

Example:

Job job = new Job();
Collection<Task> tasks = job.getTasks();
//entityManager.persist(job);
ActionPlan actionPlan = (ActionPlan) entityManager.createNamedQuery("ActionPlan.findByCommand").
                setParameter("type", RunOperation.Install).getSingleResult();
Task task = Task.getTask(actionPlan);
task.setActionPlan(actionPlan);
tasks.add(task);
task.setJob(job);

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persist() .

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Answer 1

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P.S. " ".

Session sess = factory.openSession();
Transaction tx;
try {
tx = sess.beginTransaction();
    //do some work
    ...
    tx.commit();
}
catch (Exception e) {
    if (tx!=null) tx.rollback();
    throw e;
}
finally {
    sess.close();
}

Answer 2

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Answer 3

, . flush EntityManager .

Answer 4

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, ;)

What remains of her is that I still do not understand why I cannot make a request without everything being in a constant state.