Question

I’m trying to get started with Hibernate, and when executing my program I get an error during initialization.
The exception is thrown by this class, copied from here:

package net.always_data.bastien_leonard;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtil {

    private static final SessionFactory sessionFactory = buildSessionFactory();

    private static SessionFactory buildSessionFactory() {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
            return new Configuration().configure().buildSessionFactory();
        }
        catch (Throwable ex) {
            // Make sure you log the exception, as it might be swallowed
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

}

Here is the stacktrace:

> java net/always_data/bastien_leonard/Main
Initial SessionFactory creation failed.java.lang.NoClassDefFoundError: org/hibernate/cfg/Configuration
Exception in thread "main" java.lang.ExceptionInInitializerError
    at net.always_data.bastien_leonard.HibernateUtil.buildSessionFactory(HibernateUtil.java:18)
    at net.always_data.bastien_leonard.HibernateUtil.<clinit>(HibernateUtil.java:8)
    at net.always_data.bastien_leonard.Main.main(Main.java:17)
Caused by: java.lang.NoClassDefFoundError: org/hibernate/cfg/Configuration
    at net.always_data.bastien_leonard.HibernateUtil.buildSessionFactory(HibernateUtil.java:13)
    ... 2 more
Caused by: java.lang.ClassNotFoundException: org.hibernate.cfg.Configuration
    at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:323)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:268)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:336)
    ... 3 more

I don’t know where the problem comes from, so I don’t really know where to look:

• Problem of installation? This was handled by Maven, so I guess it’s correct.
• Hibernate can’t find the configuration file?
• Problem of classpath?

I’m invoking the program from the root of the classpath, which contains my hibernate.cfg.xml file.
Here is how it looks like in practice:

> pwd
/home/bastien/info/java/hibernate/test/Test/target/classes
> echo $CLASSPATH
/home/bastien/info/java/hibernate/test/Test/target/classes
> ls -F
hibernate.cfg.xml  net/
> ls -FR
.:
hibernate.cfg.xml  net/

./net:
always_data/

./net/always_data:
bastien_leonard/

./net/always_data/bastien_leonard:
Event.class  Event.hbm.xml  HibernateUtil.class  Main.class

I’ve tried looking into the tutorial examples provided with Hibernate, but Maven can’t compile them; it complains about missing artifacts.

By the way, Maven only lets me use Hibernate 3.3.1. Is it possible to use 3.3.2 and still let Maven handle the installation?

Answer 1

“java.lang.NoClassDefFoundError”, indicating that the class loader can’t find org.hibernate.cfg.Configuration says you’ve got a CLASSPATH problem.

echo $CLASSPATH
/home/bastien/info/java/hibernate/test/Test/target/classes

You’ve got to add all the Hibernate JARs and dependencies into the CLASSPATH as well. I don’t see them in this echo.