how to prevent hibernate to insert into one table in many to many mapping ?

[Piyush Kaila]

I'm creating user profile in which user can enter their interests.
where interest is predefined list user can not select out of this list. these intrest table is already define in database.
so when user register with its interest i need to just insert UserId & InterestId (which i get from html form multiple select (sport->1, music->2)) using hibernate.

i post my problem in more details with code on stackOverflow.
http://stackoverflow.com/questions/19188751/how-to-prevent-hibernate-to-insert-into-one-table-in-many-to-many-mapping

Thanks a lot.