Caused by: org.hibernate.TransactionException: unable to commit against JDBC connection
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doCommit(JdbcTransaction.java:116) [hibernate-core-4.3.8.Final.jar:4.3.8.Final]
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:180) [hibernate-core-4.3.8.Final.jar:4.3.8.Final]
    ... 194 more
Caused by: java.sql.SQLException: You cannot commit during a managed transaction!
    at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnection.jdbcCommit(BaseWrapperManagedConnection.java:1065)
    at org.jboss.jca.adapters.jdbc.WrappedConnection.commit(WrappedConnection.java:758)
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doCommit(JdbcTransaction.java:112) [hibernate-core-4.3.8.Final.jar:4.3.8.Final]
    ... 195 more

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="connection.datasource">java:/jdbc/salome-database</property>
        <property name="hibernate.current_session_context_class">thread</property>
        <property name="hibernate.show_sql">true</property>
        <property name="hibernate.archive.autodetection">class</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

        <mapping resource="hibernate-mapping.xml"/>

    </session-factory>
</hibernate-configuration>

public static SessionFactory getSessionFactory()
{
    if (sessionFactory == null)
    {
        // loads configuration and mappings
        Configuration configuration = new Configuration().configure();
        ServiceRegistry serviceRegistry
                = new StandardServiceRegistryBuilder()
                .applySettings(configuration.getProperties()).build();

        // builds a session factory from the service registry
        sessionFactory = configuration.buildSessionFactory(serviceRegistry);
    }

    return sessionFactory;
}

public Event getById(int id)
{
    List<Event> eventList = new ArrayList<Event>();

    Session session = sessionFactory.getCurrentSession();
    session.getTransaction().begin();

    try
    {
        Query q = session.createQuery("from Event as event where event.id='" + id + "'");
        q.setCacheable(true);
        eventList = (List<Event>) q.list();
        session.getTransaction().commit();
    }

    catch (RuntimeException e)
    {
        throw e;
    }

    finally
    {
    }

    if (eventList.isEmpty())
    {
        return null;
    }
    else
    {
        return eventList.get(0);
    }
}

public void addEvent(Event event)
{
    Session session = sessionFactory.getCurrentSession();
    session.getTransaction().begin();

    try
    {
        session.save(event);
        session.getTransaction().commit();
    }

    catch (RuntimeException e)
    {
        throw e;
    }

    finally
    {
    }
}

public void deleteEvent(Event event)
{
    Session session = sessionFactory.getCurrentSession();
    session.getTransaction().begin();

    try
    {
        session.delete(event);
        session.getTransaction().commit();
    }

    catch (RuntimeException e)
    {
        throw e;
    }

    finally
    {
    }
}