Hibernate can track Session and SessionFactory usage and store statistics in the org.hibernate.stat.Statistics class. The statistics can be exposed as JMX MBean and accessed e.g. through Java VisualVM with VisualVM-MBeans plugin, bundled with Java 6 JDK.

In my case, I had to monitor an application developed with Hibernate 3.2 and Spring 2.0 deployed in Tomcat 5.5. I followed these manuals:
http://raibledesigns.com/wiki/Wiki.jsp?page=HibernateJMX
http://tomcat.apache.org/tomcat-5.5-doc/monitoring.html

but I was not able to:
– connect to the MBeanServer embedded in Tomcat remotely, although the JMX remote port was specified in Tomcat launch configuration, there was no process listening on.
– register the Hibernate StatisticsService MBean via Spring and see it in VisualVM, although there were c3p0 connection pool MBeans (magically registered somehow)

I peeked at the c3p0 source code (com.mchange.v2.c3p0.management.ActiveManagementCoordinator). They were using directly ManagementFactory.getPlatformMBeanServer() to obtain the MBean server reference and register their beans.

So I married two solutions posted in Matt Raible’s wiki:

• tell Hibernate to gather statistics; set hibernate.generate_statistics property to true
• declare Hibernate Statistics MBean in the Spring application context:

    <bean id="statisticsService" class="org.hibernate.jmx.StatisticsService">
        <property name="statisticsEnabled" value="true"/>
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean>

• Register Statistics MBean on application startup (don’t forget to add the listener to web.xml):

public class HibernateStatisticsPublisherListener implements ServletContextListener {

    private static final Log LOG = LogFactory.getLog(HibernateStatisticsPublisherListener.class);

    public void contextInitialized(ServletContextEvent servletContextEvent) {
        ApplicationContext appCtx = WebApplicationContextUtils.getRequiredWebApplicationContext(
            servletContextEvent.getServletContext());

        try {
            MBeanServer mBeanServer = ManagementFactory.getPlatformMBeanServer();
            ObjectName on = new ObjectName("Hibernate:type=statistics");
            StatisticsService mBean = (StatisticsService) appCtx.getBean("statisticsService");
            mBeanServer.registerMBean(mBean, on);
        } catch (Exception e) {
            LOG.error("Error registering Hibernate StatisticsService in the MBean server", e);
        }
    }

    public void contextDestroyed(ServletContextEvent servletContextEvent) {
    }
}

Now, start your Tomcat, connect to the local process in the VisualVM (be sure you installed VisualVM-MBeans plugin) and enjoy statistics on the MBeans tab!