Please make sure that you have specified the provider as
<provider>oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProvider</provider>
in your persistence.xml
If you have done so and still getting the exception, something has gone
wrong while creating EMF. Your console/log would have an exception trace
printed before the exception below with details.
Damaris Tellez Velazquez wrote:
> I have a little problem with that exception:
>> Exception in thread "main" javax.persistence.PersistenceException:
>> No Persistence provider for EntityManager named Service: The
>> following providers:
>> oracle.toplink.essentials.PersistenceProvider
>> oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProvider
>> Returned null to createEntityManagerFactory.
>>
>> i will be appreciated you if you can help me
>> attentively
>> damaris
>