i dont think that you can map 2 tables in single class ... you can map one table in one class and you can have more than one class mapping in one file but its not the good programming practice.. you should implement class-per-file mechanism....
i m giving this reply up to my knowledge ..this may b correct or may not be..
If you are using Hibernate3 then you can. Naveen Mishra's example doesn't map two tables to one class (though it does return data from two tables via HQL) - if you want the same behaviour via a mapping read the Hibernate documentation about the <join /> element.