I have 2 database tables (A,B), relationship between those 2 tables is One record of table A has reference to many records of table B,(One - to - Many)
When i load up my application it loads the records of table A to a drop-down list, from there if i select any record of table A, it loads the relavent records of table B (as Objects of cause) to temp List, from there i modify/add new / and delete records from/to that temp list. Now my problem is after all the playings are done, i want to update that particular record of Table A in the database table with only one call to data base using hibernate. In other words if i click save button, it has to delete records of table B (if i have already deleted that record from that temp list), add new records (if i have added new records to that temp list), modify records of table B(if i have modifyed current records of temp list) with only one call to database.
How do i do this using hibernate?

I think the following example may help you:
http://www.hibernate.org/hib_docs/v3/re ... d-cascades

Basically all you have to do is:

open a session
reattach the objects (by a call to update or merge)
flush the session (to commit the transaction)
close the session

the call to update/merge should automatically find which elements of B were already there, which are new and which disappeared.

note: The B elements must have an identifier attribute for the update/merge to work.

Hope that helps.