I'm about to start using Hibernate and looking at the hibernate site, I
see there is a Hibernate 1, 2 and now a 3.

I downloaded Hibernate 2 stable and its jar file is named
hibernate2.jar.  This would seem to indicate that each version of
hibernate is not compatible with other versions (assuming that each jar
has its version number included).

Is this the case?  Or can I just rename the jar file to hibernate.jar
and overlay it with newer versions?

Will