Why Hibernate session object's delete method is not working?

Question

Why session object's delete method is not working in GenericDAOImpl.java, neither its giving any exception nor its showing any output. All other methods working fine expect public void delete(T object), Please help me, Sorry if i asked this question in wrong way.

public class GenericDAOImpl<T> implements IGenericDAO<T> {
private SessionFactory sessionFactory;

public GenericDAOImpl(Class<T> cl, SessionFactory sessionFactory) {
    this.sessionFactory = sessionFactory;
    if (sessionFactory == null)
        throw new RuntimeException("Session factory is null!!!");
}

@Override
public T get(Class<T> cl, Long id) {
    Session session = sessionFactory.getCurrentSession();
    session.beginTransaction();
    @SuppressWarnings("unchecked")
    T element = (T) session.get(cl, id);
    session.getTransaction().commit();
    return element;
}

@Override
public T get(Class<T> cl, Serializable obj) {
    Session session = sessionFactory.getCurrentSession();
    session.beginTransaction();     
    @SuppressWarnings("unchecked")   
    T element = (T) session.get(cl, obj);
    session.getTransaction().commit();
    return element;
}

@Override
public T save(T object) {
    Session session = sessionFactory.getCurrentSession();
    session.beginTransaction();
    session.save(object);
    session.getTransaction().commit();
    return object;
}

@Override
public void update(T object) {
    Session session = sessionFactory.getCurrentSession();
    session.beginTransaction();
    session.update(object);
    session.getTransaction().commit();
}

@Override
public void delete(T object) {
    Session session = sessionFactory.getCurrentSession();
    session.beginTransaction();
    session.delete(object);
    session.getTransaction().commit();
}

@SuppressWarnings("unchecked")
@Override   
public T findUniqueByQuery(String hsql, Map<String, Object> params) {
    Session session = sessionFactory.getCurrentSession();
    session.beginTransaction();
    Query query = session.createQuery(hsql);
    if (params != null) {
        for (String i : params.keySet()) {
            query.setParameter(i, params.get(i));
        }
    }
    return (T) query.uniqueResult();
}

@SuppressWarnings("unchecked")
@Override
public List<T> query(String hsql, Map<String, Object> params) {
    Session session = sessionFactory.getCurrentSession();
    session.beginTransaction();
    Query query = session.createQuery(hsql);
    if (params != null) {
        for (String i : params.keySet()) {
            query.setParameter(i, params.get(i));
        }
    }

    List<T> result = null;
    if ((hsql.toUpperCase().indexOf("DELETE") == -1)
            && (hsql.toUpperCase().indexOf("UPDATE") == -1)
            && (hsql.toUpperCase().indexOf("INSERT") == -1)) {
        result = query.list();
    } else {
    }
    session.getTransaction().commit();

    return result;
    }

}

Answer 1

As investigated in comments, you are facing

org.hibernate.TransactionException: nested transactions not supported exception

This is happening because you began transaction and never committed or rollbacked upon an exception.

I can see one of it's case in your code. See your code below

@SuppressWarnings("unchecked")

@Override   
public T findUniqueByQuery(String hsql, Map<String, Object> params) {
    Session session = sessionFactory.getCurrentSession();
    session.beginTransaction();
    Query query = session.createQuery(hsql);
    if (params != null) {
        for (String i : params.keySet()) {
            query.setParameter(i, params.get(i));
        }
    }
    return (T) query.uniqueResult();
}

See, you began and never committed a transaction. Like wise check all other places in your project.