I have a requirement in jsp, an user can enter details in one screen and screen to follow, and has next and previous button to go to next screen. When he clicks on next button, he goes to another screen where he enters or modify some details and similarly he clicks on next button, till the final screen where he asked to confirm the details entered. once confirmed the data will be saved to database. my question is, how to know whether user has changed the values in one screen, how can I prompt him to save the values before going to next screen (technical answer). kindly let me know what is the best way to implement (save on every screen or save at the end ), kindly give the best solutions. 

what I have thought is, to hold the changed data in the HttpSession or to have Stateful session bean to hold values, so that even if the session is expired, he can login and start from the place where he has stopped.