Where is your EntityManager reference coming from? If you're using injection, I'd suggest looking through the logs for any error / warning messages that would help you figure out what is going on.
On Wed, Feb 20, 2013 at 1:50 AM, Aitor Iturriondobeitia < [email protected]> wrote: > this: > public void persist(E entity) { > entityManager.persist(entity); ** this line > } > > thanks for your answer > > > 2013/2/20 Rick Curtis <[email protected]> > > > What is at com.caf.db.dao.JpaDao.persist(JpaDao.java:20)? > > > > > > On Tue, Feb 19, 2013 at 5:08 PM, Aitor Iturriondobeitia < > > [email protected]> wrote: > > > > > hello > > > i an tring to build my firts openjpa app > > > i am readint this article ( > > > http://java.dzone.com/articles/jpa-implementation-patterns) and > building > > > it > > > for this i make this: > > > 1.- generic interface: > > > public interface IGenericDao<K, E> { > > > void persist(E entity); > > > } > > > 2.- other interface, my interface. > > > public interface IWsSrvTrackRequest extends IGenericDao<Integer, > > > Wssrvtrackrequest>{ > > > void wsSrvRequestPersist(Wssrvtrackrequest request); > > > } > > > 3.- generic JPA-DAO: > > > public abstract class JpaDao<K, E> implements IGenericDao<K, E> { > > > protected Class<E> entityClass; > > > > > > @PersistenceContext > > > protected EntityManager entityManager; > > > > > > public JpaDao() { > > > ParameterizedType genericSuperclass = (ParameterizedType) > > > getClass().getGenericSuperclass(); > > > this.entityClass = (Class<E>) > > > genericSuperclass.getActualTypeArguments()[1]; > > > } > > > public void persist(E entity) { > > > entityManager.persist(entity); > > > } > > > } > > > } > > > 4.- my jpa-dao implementation (the Wssrvtrackrequest obj is one jpa > > object > > > (entity)). > > > public class JpaWsSrvTrackRequestDaoImpl extends JpaDao<Integer, > > > Wssrvtrackrequest> implements IWsSrvTrackRequest { > > > public void wsSrvRequestPersist(Wssrvtrackrequest request){ > > > entityManager.persist(request); > > > } > > > } > > > i am make one main class: > > > public static void main(String[] args) { > > > IWsSrvTrackRequest r = new JpaWsSrvTrackRequestDaoImpl(); > > > Wssrvtrackrequest v = new Wssrvtrackrequest(); > > > v.setWssrvreqIp("la ip"); > > > v.setWssrvreqOid("oid"); > > > v.setWssrvreqOiduser("oiduser"); > > > v.setWssrvreqRequest("la request"); > > > r.persist(v); > > > } > > > > > > but it always returns one nullpointerexception. > > > Exception in thread "main" java.lang.NullPointerException > > > at com.caf.db.dao.JpaDao.persist(JpaDao.java:20) > > > at com.caf.db.dao.ll.main(ll.java:20) > > > > > > Can you help me please? > > > > > > thanks > > > > > > > > > > > -- > > *Rick Curtis* > > > -- *Rick Curtis*
