Oracle Forms

HI...guys..I have 2 questions

(1)
I need to close form after 10 minutes if user is not interacting with it for that duration. Exa.. lets say, user opened a custom form,queried data,did some changes, (here he didnt commit or save) now he left away...so, after 10 minutes form either save data and close it....or simply close it without saving data...

How can I do this...?

(2)
if one form opened by 10 different users at the same time....they queried the same record.....now if 1 user is changing data...and saving it....but user 2 is having old data...so, now user 2 will change it ...so it will replace what user 1 did...

what might be solution for this situation ???

Thanks in advance.....