I have a class mapped to a DB2 table, in which I am using the identity generator for the primary key.

In my mapping class I have something like this:

<hibernate-mapping>
<class
name="test.Example"
table="test"
>

<id
name="id"
column="id"
type="integer"
unsaved-value="0"
>
<generator class="identity">
</generator>
</id>

<property
name="someProperty"
type="int"
column="some_property"
/>
... etc ...


(the mapping was generated from Hibernate xdoclet tags.

When I try and save an instance of this class I get this exception:

net.sf.hibernate.MappingException: could not instantiate id generator
at net.sf.hibernate.id.IdentifierGeneratorFactory.create(IdentifierGeneratorFactory.java:82)
at net.sf.hibernate.mapping.SimpleValue.createIdentifierGenerator(SimpleValue.java:80)
at net.sf.hibernate.persister.AbstractEntityPersister.<init>(AbstractEntityPersister.java:630)
at net.sf.hibernate.persister.EntityPersister.<init>(EntityPersister.java:741)
at net.sf.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:41)
at net.sf.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:136)
at net.sf.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)

...etc...

Caused by: java.lang.ClassNotFoundException:
at com.ibm.ws.classloader.CompoundClassLoader.findClass(CompoundClassLoader.java(Compiled Code))
at com.ibm.ws.classloader.CompoundClassLoader.loadClass(CompoundClassLoader.java(Compiled Code))
at java.lang.ClassLoader.loadClass(ClassLoader.java(Compiled Code))
at java.lang.Class.forName1(Native Method)
at java.lang.Class.forName(Class.java(Compiled Code))
at net.sf.hibernate.util.ReflectHelper.classForName(ReflectHelper.java:75)
at net.sf.hibernate.id.IdentifierGeneratorFactory.create(IdentifierGeneratorFactory.java:76)

I have a ClassNotFoundExcpetion, but the rest of the message is blank (ie I don't know what class it is looking for).

Has anyone else seen this? Any ideas on how I can resolve this?

Thanks,
Kevin Hooke

I found out this was caused by an empty generator-class attribute in my XDoclet tag for a completely unrelated class.

Lesson learnt today: check your xdoclet tags are valid :-)