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
    at rest.QuestionRest.createDataInJSON(
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(
    at java.lang.reflect.Method.invoke(
    at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke

Here is my QuestionRest

public class QuestionRest {

private QuestionDao podcastDao;

    public Response createDataInJSON(String data) {

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

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

        public void save(Question p) {

            Session session = this.sessionFactory.openSession();
            Transaction tx = session.beginTransaction();

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" />

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