What does this error mean and how can I fix it?

I'm using this DAO class which was generated by Hibernate Tools:

/**
 * Home object for domain model class Empleados.
 * @see com.hibernate.Empleados
 * @author Hibernate Tools
 */
public class EmpleadosHome {

    private static final Log log = LogFactory.getLog(EmpleadosHome.class);

    private final SessionFactory sessionFactory = getSessionFactory();

    protected SessionFactory getSessionFactory() {
        try {
            return (SessionFactory) new InitialContext()
                    .lookup("java:/hibernate/SessionFactory");
        } catch (Exception e) {
            log.error("Could not locate SessionFactory in JNDI", e);
            throw new IllegalStateException(
                    "Could not locate SessionFactory in JNDI");
        }
    }

    public void persist(Empleados transientInstance) {
        log.debug("persisting Empleados instance");
        try {
            sessionFactory.getCurrentSession().persist(transientInstance);
            log.debug("persist successful");
        } catch (RuntimeException re) {
            log.error("persist failed", re);
            throw re;
        }
    }

    public void attachDirty(Empleados instance) {
        log.debug("attaching dirty Empleados instance");
        try {
            sessionFactory.getCurrentSession().saveOrUpdate(instance);
            log.debug("attach successful");
        } catch (RuntimeException re) {
            log.error("attach failed", re);
            throw re;
        }
    }

    pu开发者_开发百科blic void attachClean(Empleados instance) {
        log.debug("attaching clean Empleados instance");
        try {
            sessionFactory.getCurrentSession().lock(instance, LockMode.NONE);
            log.debug("attach successful");
        } catch (RuntimeException re) {
            log.error("attach failed", re);
            throw re;
        }
    }

    public void delete(Empleados persistentInstance) {
        log.debug("deleting Empleados instance");
        try {
            sessionFactory.getCurrentSession().delete(persistentInstance);
            log.debug("delete successful");
        } catch (RuntimeException re) {
            log.error("delete failed", re);
            throw re;
        }
    }

    public Empleados merge(Empleados detachedInstance) {
        log.debug("merging Empleados instance");
        try {
            Empleados result = (Empleados) sessionFactory.getCurrentSession()
                    .merge(detachedInstance);
            log.debug("merge successful");
            return result;
        } catch (RuntimeException re) {
            log.error("merge failed", re);
            throw re;
        }
    }

    public Empleados findById(java.lang.Integer id) {
        log.debug("getting Empleados instance with id: " + id);
        try {
            Empleados instance = (Empleados) sessionFactory.getCurrentSession()
                    .get("com.hibernate.Empleados", id);
            if (instance == null) {
                log.debug("get successful, no instance found");
            } else {
                log.debug("get successful, instance found");
            }
            return instance;
        } catch (RuntimeException re) {
            log.error("get failed", re);
            throw re;
        }
    }

    public List findByExample(Empleados instance) {
        log.debug("finding Empleados instance by example");
        try {
            List results = sessionFactory.getCurrentSession().createCriteria(
                    "com.hibernate.Empleados").add(Example.create(instance))
                    .list();
            log.debug("find by example successful, result size: "
                    + results.size());
            return results;
        } catch (RuntimeException re) {
            log.error("find by example failed", re);
            throw re;
        }
    }
}

This is my hibernate.cfg.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory name="SessionFactory">
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.password">1234</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3307/ejemplos</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
        <property name="connection.autocommit">true</property>
        <property name="current_session_context_class">jta</property>
        <mapping resource="com/hibernate/Empleados.hbm.xml" />
    </session-factory>
</hibernate-configuration>

I get the following exception:

org.hibernate.HibernateException: Unable to locate current JTA transaction
    at org.hibernate.context.JTASessionContext.currentSession(JTASessionContext.java:88)
    at org.hibernate.impl.SessionFactoryImpl.getCurrentSession(SessionFactoryImpl.java:574)
    at com.hibernate.EmpleadosHome.findById(EmpleadosHome.java:95)
    at org.apache.jsp.index_jsp._jspService(index_jsp.java:75)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:322)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:249)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)
    at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)
    at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
    at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
    at java.lang.Thread.run(Thread.java:619)

I'm not sure if your environment is supporting JTA and automatic transaction handling (at least, not with your current setup). And actually, if you don't plan to access multiple transactional resources, my advice would be to use the default JDBC approach i.e. to modify your hibernate.cfg.xml as follow:

<property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>
<property name="current_session_context_class">thread</property>

And regenerate the code (I don't have much experience with the DAO generated by Hibernate Tools, I don't guarantee the result).

Checkout this page: https://forum.hibernate.org/viewtopic.php?f=1&t=951402

Looks like it might be a configuration issue of your appserver

Replace getCurrentSession() with openSession()