public void init() {
        // Perform initializations inherited from our superclass
        super.init();
        // Perform application initialization that must complete
        // *before* managed components are initialized
        // TODO - add your own initialization code here
        ...
        // Perform application initialization that must complete
        // *after* managed components are initialized
        // TODO - add your own initialization code here
        List personList = null;
        try{
            Session session =
                    HibernateUtil.getSessionFactory().getCurrentSession();
            Transaction tx = session.beginTransaction();
            Query q = session.createQuery("from Person");
            personList = (List) q.list();
        } catch(Exception e) {
            e.printStackTrace();
        }
        personOptions = new Option[personList.size()];
        Iterator iter = personList.iterator();
        int i=0;
        while (iter.hasNext()) {
            Person person = (Person) iter.next();
            Option opt = new Option("" + person.getPersonId(),
                    person.getName());
            personOptions[i++] = opt;
        }
    }

public class TripDataProvider extends ObjectListDataProvider{
    private ArrayList tripsList = new ArrayList();
    //  Note: to eliminate warnings when using Java SE 1.5, use instead
    //  private ArrayList<Trip> tripsList = new ArrayList<Trip>();

    /** Creates a new instance of tripDataProvider */
    public TripDataProvider() {

        // Put in dummy data for design time
        tripsList.add(new Trip());

        // Wrap the list
        setList(tripsList);
    }

    public void refreshTripsList(Integer personId){
        tripsList.clear();
        try{
            Session session =
                    HibernateUtil.getSessionFactory().getCurrentSession();
            Transaction tx = session.beginTransaction();
            Person person =
                    (Person)
                    session.load(Person.class, personId);
            Set personTrips = (PersistentSet)person.getTrips();
            tripsList.addAll(personTrips);
            tx.commit();
        } catch(Exception e){
            e.printStackTrace();
        }
    }
}

    public void prerender() {
        try {
            if (dropDown1.getSelected() == null ) {
                Option firstPerson = getSessionBean1().getPersonOptions()[0];
                getSessionBean1().getTripDataProvider().refreshTripsList(
                        new Integer((String)firstPerson.getValue()));
            }
        } catch (Exception ex) {
            log("Error Description", ex);
            error(ex.getMessage());
        }
    }

    public void dropDown1_processValueChange(ValueChangeEvent event) {
        try {
            Integer personId =
                    new Integer((String)dropDown1.getSelected());
            getSessionBean1().getTripDataProvider().refreshTripsList(
                    personId);
        } catch(Exception ex) {
            log("Error getting Person List : ", ex);
            error("Error getting Person List: " + ex.getMessage());
        }
    }