Skip to main content
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [List Home]
Re: [eclipselink-users] EntityManager life-cycle.. 
Hi Paul,
Is your plain Unit test multi-threaded? I am trying to get my mind around how processor can be null at that point in the code - seems impossible in a single-threaded application.
My current theory is that somehow the initialization of the EntityManagerFactory is still occuring at the point where you try to acquire the EntityManager either because some other thread is causing that to occur, or because there is some JVM atomicity issue with the static creation of the EntityManagerFactory and the static initializer for your racks. 

-Tom

Paul Harrison wrote:

On 2011-03 -29, at 08:43, Paul Harrison wrote:


as Racks are the basic containers for all other objects and there need to be two pre-existing for the application to be able to function - stationRack and baselineRack are static members of Rack. The code that does the equivalent of what causes the error below runs fine in a unit test - so it seems that it is running within Netbeans RCP that the problem occurs - perhaps it is to do with an interaction between the classloading requirements of Eclipselink and Netbeans RCP....


Actually I was looking and the unit test does other things first - if I isolate the unit test to do exactly what is happening in Netbeans RCP then exactly the same happens (the NPE) in a pure unit test  - the following is the first (non-static) piece of code

RackJpaController jpa = new RackJpaController();
List<Rack> rackList = jpa.findRackEntities();


so there seems to be an interaction between the static initialization in Rack

    static {
try { 
            RackJpaController instance = new RackJpaController();
            if((stationRack = instance.findRack(Integer.valueOf(255))) == null){
                stationRack = new Rack(Integer.valueOf(255));
                stationRack.setName("Station");
                instance.create(stationRack);
            }
            if((baselineRack = instance.findRack(Integer.valueOf(101))) == null){
                baselineRack = new Rack(Integer.valueOf(101));
                baselineRack.setName("Baseline");
                instance.create(baselineRack);
            }
        } catch (PreexistingEntityException e) {
            throw new RuntimeException("A Rack has already been created", e);
        } catch (Exception e) {
            throw new RuntimeException("Error creating rack", e);
        }
} 

and the use of Rack as the List generic type specifier - the code for the jpa.findRackEntities() is

   public List<Rack> findRackEntities() {
        return findRackEntities(true, -1, -1);
    }

    public List<Rack> findRackEntities(int maxResults, int firstResult) {
        return findRackEntities(false, maxResults, firstResult);
    }

    private List<Rack> findRackEntities(boolean all, int maxResults, int firstResult) {
        EntityManager em = getEntityManager();
        try {
            CriteriaQuery cq = em.getCriteriaBuilder().createQuery();
            cq.select(cq.from(Rack.class));
            Query q = em.createQuery(cq);
            if (!all) {
                q.setMaxResults(maxResults);
                q.setFirstResult(firstResult);
            }
            return q.getResultList();
        } finally {
            em.close();
        }
    }

I can work round this problem by creating an instance of Rack before the "List<Rack> rackList = jpa.findRackEntities();" to get the static initializers done separately.

I can send you a complete maven project with just the relevant classes if you want to investigate the issue further...

Regards,
	Paul.

_______________________________________________
eclipselink-users mailing list
eclipselink-users@xxxxxxxxxxx
https://dev.eclipse.org/mailman/listinfo/eclipselink-users

Back to the top