Hi! I want to make a tool that will autogenerate annotations (via Javassist) to some classes.

I have doubts about the classloaders... suppose I have House.java, I make magic with Javassist and then I have a new version of House.java, with Hibernate annotations...

Then, I will "start" hibernate with AnnotationConfiguration, using configuration.addAnnotatedClass(..) and I will pass the new version of House.java, it should work by now.

If I get to this point, everything working, ¿shouldn't I have some problems with both versions of House.java?

I mean, if I want to create a new House and I do this:
HibernateUtil.getSession().save( newHouse );

¿What happens if newHouse was using the first version (the one who did NOT have annotations)? I think it shouldn't work.

Any ideas? Thanks!

Answering myself: it IS possible. You can create a "meta language" using annotations, much simpler than real hibernate annotations. The only "cons" of processing and injecting annotations at runtime, is that you need reloading capabilities, in my case, I use javarebel, it does the job.

So, using javarebel.. no classLoader problems! Javassist does the rest.