[INFO] Environment - -Hibernate 2.0.2
[INFO] Environment - -loaded properties from resource hibernate.properties: {hibernate.connection.driver_class=COM.ibm.db2.jdbc.app.DB2Driver, hibernate.cglib.use_reflection_optimizer=true, hibernate.dialect=net.sf.hibernate.dialect.DB2Dialect, hibernate.connection.username=db2admin, hibernate.connection.url=jdbc:db2:strutsdb, hibernate.show_sql=true, hibernate.connection.password=db2admin, hibernate.connection.pool_size=20, hibernate.statement_cache.size=6}
[INFO] Environment - -using CGLIB reflection optimizer
[INFO] Environment - -JVM proxy support: true
[INFO] Configuration - -Mapping resource: com/ibm/hibernate_article/Job.hbm.xml
[INFO] Binder - -Mapping class: com.ibm.hibernate_article.Job -> JOB
[INFO] Configuration - -Mapping resource: com/ibm/hibernate_article/Product.hbm.xml
[INFO] Binder - -Mapping class: com.ibm.hibernate_article.Product -> PRODUCT
[INFO] Configuration - -Mapping resource: com/ibm/hibernate_article/Person.hbm.xml
[INFO] Binder - -Mapping class: com.ibm.hibernate_article.Person -> PERSON
[INFO] Configuration - -Mapping resource: com/ibm/hibernate_article/Timesheet.hbm.xml
[INFO] Binder - -Mapping class: com.ibm.hibernate_article.Timesheet -> TIMESHEET
[INFO] Configuration - -Mapping resource: com/ibm/hibernate_article/Lineitem.hbm.xml
[INFO] Binder - -Mapping class: com.ibm.hibernate_article.Lineitem -> LINEITEM
[INFO] Configuration - -Mapping resource: com/ibm/hibernate_article/Client.hbm.xml
[INFO] Binder - -Mapping class: com.ibm.hibernate_article.Client -> CLIENT
[INFO] Configuration - -processing one-to-many association mappings
[INFO] Binder - -Mapping collection: com.ibm.hibernate_article.Job.lineitems -> LINEITEM
[INFO] Binder - -Mapping collection: com.ibm.hibernate_article.Product.jobs -> JOB
[INFO] Binder - -Mapping collection: com.ibm.hibernate_article.Person.timesheets -> TIMESHEET
[INFO] Binder - -Mapping collection: com.ibm.hibernate_article.Timesheet.lineitems -> LINEITEM
[INFO] Binder - -Mapping collection: com.ibm.hibernate_article.Client.products -> PRODUCT
[INFO] Configuration - -processing foreign key constraints
[INFO] SessionFactoryImpl - -building session factory
[INFO] Dialect - -Using dialect: net.sf.hibernate.dialect.DB2Dialect
[INFO] DriverManagerConnectionProvider - -Hibernate connection pool size: 20
[INFO] DriverManagerConnectionProvider - -using driver: COM.ibm.db2.jdbc.app.DB2Driver at URL: jdbc:db2:strutsdb
[INFO] DriverManagerConnectionProvider - -connection properties: {user=db2admin, password=db2admin}
[INFO] PreparedStatementCache - -prepared statement cache size: 6
[INFO] SessionFactoryImpl - -Use outer join fetching: true
[INFO] SessionFactoryImpl - -Use scrollable result sets: true
[INFO] SessionFactoryImpl - -echoing all SQL to stdout
java.lang.ExceptionInInitializerError: java.lang.RuntimeException: couldn't get connection
at com.ibm.hibernate_article.HibernateTest.<clinit>(HibernateTest.java:54)
at java.lang.reflect.Constructor.newInstance(Native Method)
at junit.framework.TestSuite.addTestMethod(TestSuite.java:102)
at junit.framework.TestSuite.<init>(TestSuite.java:66)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.getTest(RemoteTestRunner.java:270)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:307)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:218)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:151)

The ibm sample you looked, used Hibernate 1.2.4. You are using Hibernate 2.0.2. Please look at a more up to date tutorial.
http://www.hibernate.org/78.html is a good start

I am using the article as a shell, I got the original sample to work.

Here is what I see happening:
Middlegen generate something like this:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >

<hibernate-mapping>

<!--
Created by Middlegen Hibernate plugin

http://boss.bekk.no/boss/middlegen/
http://hibernate.sourceforge.net/
-->

<class
name="com.ibm.hibernate_article.Product"
table="PRODUCT"
>

by taking out the part:
<!--
Created by Middlegen Hibernate plugin

http://boss.bekk.no/boss/middlegen/
http://hibernate.sourceforge.net/
-->
it now works.
Thanks again.