You may want to implement concurrent editing without locking. Basically, when you get the form for edit you save the current values and when saving you compare the old and the new values and only update the changed ones. If the old value does not match what is currently stored in the database then you show a conflict warning to the user.
See this post for a deep explanation: http://jim-mcbeath.blogspot.com/2009/02/concurrent-editing-without-locking.html
Please, take a look at:
https://github.com/spring-projects/spring-petclinic/issues/433
You can see a video and sample code.
Will that meet your requirements?