jersey + spring + hibernate beans configuration

I have problem with my web app configuration. I receive null pointer exception when I want to save my data via Hibernate

com.sun.jersey.spi.container.ContainerResponse.mapMappableContainerException The RuntimeException could not be mapped to a response, re-throwing to the HTTP container
 java.lang.NullPointerException
    at rest.QuestionRest.createDataInJSON(QuestionRest.java:42)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke

Here is my QuestionRest

@Component
@Path("/question")
public class QuestionRest {

@Autowired
private QuestionDao podcastDao;

 @POST
    @Path("/post")
    @Consumes(MediaType.TEXT_PLAIN)
    public Response createDataInJSON(String data) {

    Question question = new Question();
    person.setAnswer("Pankaj " +  data);

    podcastDao.save(question);
    String result = "Data post: "+data;
    return Response.status(200).entity(result).build(); 
}

This is my implementation of QuestionDao:

public class QuestionDaoImpl implements QuestionDao {


        private SessionFactory sessionFactory;

        @Autowired
        public void setSessionFactory(SessionFactory sessionFactory) {
            this.sessionFactory = sessionFactory;
        }

        @Override
        public void save(Question p) {

            Session session = this.sessionFactory.openSession();
            Transaction tx = session.beginTransaction();
            session.persist(p);
            tx.commit();
            session.close();
        }

This is interface of Dao:

public interface QuestionDao {

    public void save(Question p);

    public List<Question> list();

}

Thsi is my bean:

<bean id="questionAnswerDao" class="dao.QuestionDaoImpl">
        <property name="sessionFactory" ref="hibernate4AnnotatedSessionFactory" />
    </bean>

My aim of this application is to save incoming data in database. I think the error may be triggered by wrong annotations.