Question

I am a Hibernate newbie, attempting a small hibernate example with an embedded Derby database. I am developing in eclipse. I am not using Spring or Maven, I am not setting up a web application, I have no application server. I will no doubt use some of those if the project gets bigger, but right now I’m just trying to get this example to work.

The error I am getting is:

Exception in thread "main" org.hibernate.MappingNotFoundException: resource: javabeat/net/hibernate/EmployeeInfo.hbm.xml not found

and sometimes just:

Exception in thread "main" org.hibernate.MappingNotFoundException: resource: EmployeeInfo.hbm.xml not found

Here is my code; I have marked where the error appears to be coming from – eclipse console shows the exception there and stops running, and it’s the logical place:

package javabeat.net.hibernate;

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

public class JavaBeatHibernateExample
{
  public static void main(String args[]) throws Exception
  {

    configureDerbyEmbedded();

    Configuration cfg = new Configuration();
    cfg.addClass(javabeat.net.hibernate.EmployeeInfo.class);

    cfg.setProperty("hibernate.connection.driver_class", "org.apache.derby.jdbc.EmbeddedDriver");
    cfg.setProperty("hibernate.connection.password", "password");
    cfg.setProperty("hibernate.connection.url", "jdbc:derby:myEmbeddedDB;create=true");
    cfg.setProperty("hibernate.connection.username", "admin");
    cfg.setProperty("hibernate.dialect", "org.hibernate.dialect.DerbyDialect");
    cfg.setProperty("cache.provider_class", "org.hibernate.cache.NoCacheProvider");

    // Exception almost certainly generated here.
    cfg.addResource("EmployeeInfo.hbm.xml");

    cfg.setProperty("hibernate.current_session_context_class", "thread");
    cfg.setProperty("hibernate.show_sql", "true");
    SessionFactory sessionFactory = cfg.buildSessionFactory();
    Session session = sessionFactory.openSession();
    Transaction transaction = session.beginTransaction();
    transaction.begin();
    EmployeeInfo employeeInfo = new EmployeeInfo();
    employeeInfo.setSno(1);
    employeeInfo.setName("KamalHasan");
    session.save(employeeInfo);
    transaction.commit();
    session.close();
  }

  private static void configureDerbyEmbedded() 
      throws ClassNotFoundException, IllegalAccessException, InstantiationException
  {
    Class.forName("org.apache.derby.jdbc.EmbeddedDriver").newInstance();
  }
}

I have the folders in eclipse set up as follows

CarRepair
--src
----javabeat
------net
--------hibernate
----main
------resources
--------javabeat
----------net
------------hibernate

I have an EmployeeInfo.hbm.xml, and I have put it in the following places:
src/javabeat/net/hibernate
main/resources/javabeat/net/hibernate
main/resources

And I always get the above exception. In the first, it just says it cannot find the XML file; in the latter two, it prepends javabeat/net/hibernate in front of the XML filename in the error message.

Is the file supposed to be somewhere else, or is there something else I’m supposed to be doing?

EDIT: Could it be something in the xml file itself, with a misleading error message?

    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >
    <hibernate-mapping>
        <class name="javabeat.net.hibernate.EmployeeInfo" table="Employee_Info">
            <id name="sno" column="sno" type="java.lang.Integer">
            </id>
            <property name="name" column="name" type="java.lang.String"/>
        </class>
    </hibernate-mapping>

Answer 1

You have quite a special directory layout. Assuming src is a source folder in Eclipse, it will copy all the non-Java files to the classes or bin directory (or whatever directory name you chose for the compiled classes), and the EmployeeInfo.hbm.xml should be directly under src, since you’re telling Hibernate to load it from the root of the classpath:

cfg.addResource("EmployeeInfo.hbm.xml");

If you place it in main/resources, the code to load it should be

cfg.addResource("main/resources/EmployeeInfo.hbm.xml");

Why don’t you use your own package hierarchy, and thus use the following directory tree:

src
  com
    rcook
      myapp