Hi all, I got a problem and here it is,

I have a application and it is subjected for data enter, edit, and view. There are several users here for use this application.
Several users can view same data at same time and also edit can be done.
If two users open same data element, lets say user 'A' and user 'B' and both they view same data element at same time.
lets say that data element is 'Hibernate' then user A edit this data element and save it as 'Spring'. This happens while data element is being viewed by user B.
Now actual data element is 'Spring'(since user A saved it like that).
Now user B saved data element without any modification and it is saved as 'Hibernate'(since both users had open same element).

Now in database the actual data value is 'Hibernate', but user A saved it as 'Spring'. Ok now conflict has taken place.
User A view data again and see that data value is still 'Hibernate', and he cannot think about this. He saved data and now seems it is not saved.

1. What was happened?
2. What is the solution for this which Hibernate can be given?
3. Is Versioning the solution for this situation?
4. If versioning is the solution, how can it be done? (simple procedure to versioning)