I think it depends if you want to have mapped one table or all tables. You can do it by managing mappings(with one class) or by combining changes in mappings with building new classes(I don't think there is good solution for this in hibernate, maybe using dynamic-class, but it is new developed feature). You would need to build new SessionFactory and Sessions. On this page you should find more clues
http://www.hibernate.org/171.html
Btw - I am not database developer, but building new daily tables seems to be really bad database design...