I have one entity - User. It is described by User.class.
Hibernate creates one table per entity, so when I call session.save(user)
I know this question was asked long time ago. But I would like to suggest an alternative way, without using any of hibernate things. For those who don't want to use xml configuration.
Declare an interface with getter and setter methods of commun columns, then make your tow entity classes implement this interface. Leave the mapping annotations in this two entity class as usual, then in your code, you can invoke method of this interface instead.