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;
    }

}

thanks @sᴜʀᴇsʜᴀᴛᴛᴀ now its giving org.hibernate.TransactionException: nested transactions not supported exception, but why ? — Praveen Rawat
– Praveen Rawat, Commented Sep 29, 2015 at 16:29
Before beginTransaction() check if check if there is already an open transaction. — Douglas Nassif Roma Junior
– Douglas Nassif Roma Junior, Commented Sep 29, 2015 at 16:59

Suresh Atta · Accepted Answer · 2015-09-29 16:35:06Z

2

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.

answered Sep 29, 2015 at 16:35

Suresh Atta

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2 Comments

Praveen Rawat Over a year ago

thanks @SURESH you are right, when i made this changes T result = (T) query.uniqueResult(); session.getTransaction().commit(); return result; then delete method is also working fine, thanks again bro :)

Suresh Atta Over a year ago

@PraveenRawat Glad to help Praveen.

S'chn T'gai Spock · Accepted Answer · 2016-10-10 07:26:30Z

2

I have the same problem. Although I was not using transaction at all. I was using namedQuery like this :

Query query = session.getNamedQuery(EmployeeNQ.DELETE_EMPLOYEES);
int rows = query.executeUpdate();
session.close();

It was returning 2 rows but the database still had all the records. Then wrap up the above code with this :

Transaction transaction = session.beginTransaction();
Query query = session.getNamedQuery(EmployeeNQ.DELETE_EMPLOYEES);
int rows = query.executeUpdate();
transaction.commit();
session.close();

Then it started working fine. I was using SQL server. But I think if we use h2 above code (without transaction) will also work fine.

answered Oct 10, 2016 at 7:26

S'chn T'gai Spock

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Comments

Andres · Accepted Answer · 2015-09-29 16:30:08Z

1

org.hibernate.TransactionException: nested transactions not supported exception

Most probably you're not closing your session after an update or insert, and then you're doing the delete.

answered Sep 29, 2015 at 16:30

Andres

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