entitymanager.find method

[anisha.silva]

HI,

I have a class Customer and Vehicle. Fist a customer needs to be added to the application. when a vehicle is being added the customer id needs to be added also

so i wrote the code as below

@Override
    public void addVehicle( String make, String model, String year, String reg, String vin, String miles,String cid) {

        Vehicle v = new Vehicle();
        //v.setVehicleid(id);
        v.setMake(make);
        v.setModel(model);
        v.setVehicleyear(Integer.parseInt(year));
        v.setRegno(reg);
        v.setVin(vin);
        v.setMiles(Integer.parseInt(miles));
        Customer c;

        try{
            **c = customerService.findCustomer(cid);**
            v.setCusid(c);
        }
            catch(Exception e)
        {
        System.out.printf("error " + e.toString());
        }

        entityManager.persist(v);
    }

the line which is bold throws an null point exceptoin. i searched for the reason it says if there is no record in the db it will throw a nullpointer exception. but i have a record in the db.
what could be the reason ?

@PermitAll
    public Customer findCustomer(String customerID) {
        return entityManager.find(Customer.class, customerID); 
    }

appreciate a reply
thanks

[stultuske]

ehm .. yeah, you have a record in your DB. do you have a record with that customerID? add a print statement in your findCustomer method, just to print your customerID, so you can verify it is what you think it is.

[JamesCherrill]

Maybe the variable customerService is null at that point - if you posted the exact complete exception messgage then it would probably be clearer, or try printing customerService there to confirm.

[anisha.silva]

yes i have a record in the database, i think the CustomerService is null
y is that

@Stateless
public class VehicleService implements VehicleServiceRemote {

    //@EJB
    CustomerService customerService;

    @PersistenceContext(unitName = "autodealerPU")
    private EntityManager entityManager;

    @Override
    public void addVehicle( String make, String model, String year, String reg, String vin, String miles,String cid) {

        Vehicle v = new Vehicle();
        //v.setVehicleid(id);
        v.setMake(make);
        v.setModel(model);
        v.setVehicleyear(Integer.parseInt(year));
        v.setRegno(reg);
        v.setVin(vin);
        v.setMiles(Integer.parseInt(miles));

        Customer c;

        try{
            c = customerService.findCustomer(cid);
            v.setCusid(c);
        }
        catch(Exception e)
        {
             System.out.printf("error " + e.toString());
        }
        entityManager.persist(v);
    }

attached is a screen shot also

 @PermitAll
    public Customer findCustomer(String customerID) {
        return entityManager.find(Customer.class, customerID); 
    }

[JamesCherrill]

If that's all the code then you declare customerService on line 5, but nowhere do you give it a value, so it's still null (uninitialised).

[stultuske]

so you'll need to inject or instantiate it. if it's null, it 's just like an empty box. you can't get anything out of it, untill there's actually something in there.

[anisha.silva]

when i did this
c = entityManager.find(Customer.class,cid);

also return null

the Vehicle Entity class is as follow

@OneToMany(mappedBy = "vehicleid")
    private Collection<Appointment> appointmentCollection;
    @JoinColumn(name = "CUSID", referencedColumnName = "CUSID")
    @ManyToOne
    private Customer cusid;

why is that

appreciate a reply
thanks

[anisha.silva]

Hey thaks everyone for the help
i found the answer

public void addVehicle( String make, String model, String year, String reg, String vin, String miles,String cid) {

        Vehicle v = new Vehicle();
        //v.setVehicleid(id);
        v.setMake(make);
        v.setModel(model);
        v.setVehicleyear(Integer.parseInt(year));
        v.setRegno(reg);
        v.setVin(vin);
        v.setMiles(Integer.parseInt(miles));        

        Customer c    = entityManager.find(Customer.class, Integer.parseInt(cid));
        v.setCusid(c);

        entityManager.persist(v);
    }

in the find method i had send in the wrong type for the primary key. the primary is an integer, so have to send an interger parameter to the find method

thanks for the help