Hibernate version: 3.0

Mapping documents:
hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://localhost:8080/IPC-Implementation/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">org.gjt.mm.mysql.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/ipcdb</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">password</property>
<property name="show_sql">false</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>

<!-- Mapping files -->
<mapping resource="humanuser.hbm.xml" />
<mapping resource="student.hbm.xml" />
<mapping resource="professor.hbm.xml" />
<mapping resource="systemmanager.hbm.xml" />
<mapping resource="course.hbm.xml" />
<mapping resource="courseoffering.hbm.xml" />
<mapping resource="enrolment.hbm.xml" />
</session-factory>
</hibernate-configuration>


humanuser.hbm.xml:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="SubsystemDesign.Didactics.Classes">
<class name="HumanUser" table="humanuser">
<id name="emailAddress" type="string" column="emailaddress">
<generator class="assigned"/>
</id>
<property name="name">
<column name="name"/>
</property>
<property name="surname">
<column name="surname"/>
</property>
<property name="ID_Number">
<column name="idnumber"/>
</property>
<property name="enabled">
<column name="enabled"/>
</property>
</class>
</hibernate-mapping>



student.hbm.xml:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="SubsystemDesign.Didactics.Classes">
<joined-subclass name="Student" extends="HumanUser" table="student">
<key column="emailaddress"/>
<set name="enrolments">
<key column="student" not-null="true"/>
<one-to-many class="Enrolment"/>
</set>
</joined-subclass>
</hibernate-mapping>



Code between sessionFactory.openSession() and session.close():

Session s = sf.openSession();
Transaction t = s.beginTransaction();
t.begin();
s.save(this);
t.commit();


Full stack trace of any exception that occurs:
org.hibernate.MappingException: Unknown entity: SubsystemDesign.Didactics.Classes.Student
org.hibernate.impl.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:550)
org.hibernate.impl.SessionImpl.getEntityPersister(SessionImpl.java:1338)
org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:98)
org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:187)
org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:172)
org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:535)
org.hibernate.impl.SessionImpl.save(SessionImpl.java:523)
org.hibernate.impl.SessionImpl.save(SessionImpl.java:519)
SubsystemDesign.Didactics.Classes.HumanUser.store(HumanUser.java:251)
SubsystemDesign.Didactics.Classes.Student.create(Student.java:97)
SubsystemDesign.Didactics.Classes.StudentRegistrationController.createStudent(StudentRegistrationController.java:80)
SubsystemDesign.Didactics.Classes.AccountManagerDispatcher.createStudent(AccountManagerDispatcher.java:169)
SubsystemDesign.Didactics.Classes.StudentRegistrationServlet.doPost(StudentRegistrationServlet.java:96)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)




Name and version of the database you are using: MySQL 4.1

Note:
We are developing a web application with Eclipse. The application server classpath contains the directories:
<project root dir>
<project root dir>/build/classes

Both the cfg.xml file and the hbm.xml files are in <project root dir>/build/classes.

Thanks for your attention.

The previous problem was fixed placing the mapping files in the java files' directory, named <project root dir>/src/SubsystemDesign/Didactics/Classes

Therefore, the main mapping configuration file (hibernate.cfg.xml) looks like:



The mapping files are:


humanuser.cfg.xml



student.cfg.xml



The code accessing Hibernate is the same posted previously, but now the exception stack trace is:




Just to point out, this web application runs on Tomcat 5.5.26. The application server is started from Eclipse workbench and the classpath contains <project root dir>, <project root dir>/WebContent (I mean the directories in the workspace, not those ones on the server, may it be a problem) and the default libraries added by Eclipse.

Just as a note, sometimes you'll see this problem when you have left the @Entity tag off a POJO when you're using Hibernate3 and JPA Annotations.