So if you add a <version name="version" column="update_count" /> tag 
to your class's hibernate mapping, which the Persistent base class has 
a version property, the generated class will hide the base class's 
property and accessors!!

What this means is that if you want to use the pattern referenced on 
this page you should declare the version (and id) methods as abstract 
and then use a consistent naming convention in the generated classes 
for those properties.

Also, for generality, it's best not to specify the type of the id 
property in such a limited way.