Why does every thread in my application use a different hibernate session?
- by Ittai
Hi,
I have a web-application which uses hibernate and for some reason every thread (httprequest or other threads related to queueing) uses a different session.
I've implemented a HibernateSessionFactory class which looks like this:
public class HibernateSessionFactory {
private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
private static Configuration configuration = new AnnotationConfiguration();
private static org.hibernate.SessionFactory sessionFactory;
static {
try {
configuration.configure(configFile);
sessionFactory = configuration.buildSessionFactory();
} catch (Exception e) {}
}
private HibernateSessionFactory() {}
public static Session getSession() throws HibernateException {
Session session = (Session) threadLocal.get();
if (session == null || !session.isOpen()) {
if (sessionFactory == null) {
rebuildSessionFactory();//This method basically does what the static init block does
}
session = (sessionFactory != null) ? sessionFactory.openSession(): null;
threadLocal.set(session);
}
return session;
}
//More non relevant methods here.
Now from my testing it seems that the threadLocal member is indeed initialized only once when the class is first loaded by the JVM but for some reason when different threads access the getSession() method they use different sessions. When a thread first accesses this class (Session) threadLocal.get(); will return null but as expected all other access requests will yeild the same session. I'm not sure how this can be happening as the threadLocal variable is final and the method threadLocal.set(session) is only used in the above context (which I'm 99.9% sure has to yeild a non null session as I would have encountered a NullPointerException at a different part of my app).
I'm not sure this is relevant but these are the main parts of my hibernate.cfg.xml file:
<hibernate-configuration>
<session-factory>
<property name="connection.url">someURL</property>
<property name="connection.driver_class"> com.microsoft.sqlserver.jdbc.SQLServerDriver</property>
<property name="dialect">org.hibernate.dialect.SQLServerDialect</property>
<property name="hibernate.connection.isolation">1</property>
<property name="hibernate.connection.username">User</property>
<property name="hibernate.connection.password">Password</property>
<property name="hibernate.connection.pool_size">10</property>
<property name="show_sql">false</property>
<property name="current_session_context_class">thread</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<property name="hibernate.cache.use_second_level_cache">false</property>
<property name="hibernate.cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Mapping files -->
I'd appreciate any help granted and of course if anyone has any questions I'd be happy to clarify.
Ittai
