i use Hibernate2.1 and tools.

run ddl2hbm.bat generate java code and hbm xml.

then i choose use hibernate Types to generate code

for emp and dept tables on scott/tiger.

and write 2 method use following query :

Query query = session.createQuery("select t from Emp as t");
Query query = session.createQuery("select t from Dept as t");

and when i list the results. the Dept no problem

but to list the emp occur Exception like this:

net.sf.hibernate.PropertyAccessException:
exception setting property value
with CGLIB
(set hibernate.cglib.use_reflection_optimizer=false for more info)
setter of com.yan.jdo.Emp.setComm

then i re-generate code choose use javaTypes.

and no error occur

setComm most likely accepts a type which is not compatible with the values Hibernate is trying to set. Most likely it is a int and you have null values in the db.