type set.

Why is this happening, I don't see that requeriement in any of the examples.

[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 file: Job.hbm.xml
[INFO] Binder - -Mapping class: com.ibm.hibernate_article.Job -> JOB
[INFO] Configuration - -Mapping file: Product.hbm.xml
[ERROR] XMLHelper - -Error parsing XML: Product.hbm.xml(46) <org.xml.sax.SAXParseException: Attribute "role" is required and must be specified for element type "set".>org.xml.sax.SAXParseException: Attribute "role" is required and must be specified for element type "set".
at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
at org.apache.xerces.util.ErrorHandlerWrapper.error(Unknown Source)
at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.addDTDDefaultAttrsAndValidate(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.handleStartElement(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.startElement(Unknown Source)
at org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.dom4j.io.SAXReader.read(SAXReader.java:339)
at org.dom4j.io.SAXReader.read(SAXReader.java:219)
at net.sf.hibernate.cfg.Configuration.addFile(Configuration.java:155)
at com.ibm.hibernate_article.HibernateTest.<clinit>(HibernateTest.java:43)
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)

You're using hibernate 2.x and your xml file refet to the 1.1 DTD.
In Product.hbm.xml, change the DTD to

I had a similar problem, for similar reasons.
I tried the fix and it didn't work. Then I looked best and smiled.

I suggest you try the following instead

<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

It worked for me.

Typo :)