HHH-9231 Rolled back entity insert remains in level 2 collection cache in JBoss EAP 6

Issue

• A OneToMany association is defined between two entity types

@Entity
public class Department {
    @OneToMany(...)
    private List<Employee> employees;
}

@Entity
public class Employee {
    @ManyToOne(...)
    private Department department;
}

• In a transaction, create an instance referencing the "One" class without updating the association collection, flush the session, initialize the association collection then rollback

    Department dept = ... // load a department but do not initialize its employees list
    entityManager.persist(new Employee("John Smith", dept));
    entityManager.flush()
    List<Employee> worksIn = dept.getEmployees();
    tx.rollback();

• After rollback, the association collection retains a reference to the non-existent (rolled back) entity and access to the association may result in javax.persistence.EntityNotFoundException