I stuck to the specs and examples shown at oracle
Javadocs at Oracle
I stuck to a simple text editor (textpad) and didn't include any screenshots. From memory you can either use, plain ascii text file, html or online (part of app rather than on internet). Text files are by far the simplest.
There is some javadoc checking in eclipse such as making sure nothing is missing. I generated the docs and got a friend to proof read it for mistakes etc.
As for the exam, just make sure you know your project well. You will need to explain why you did certain things the way you did and maybe discribe part or its usage.
I used log4j while writing the app and then removed all logging at the end. All checked exceptions were translated into meaningful error messages. Logging is not a must requirement.
I didn't set full screen but it could be maximized without any problems.
I used a facade so that i could split the locking and data access up but if you think you way is justified then i can't see a problem.
MAKE SURE YOU WRITE ABOUT ALL YOUR DESIGN CHOICES!
The must requirements will be dependant on you individual assignment. How about doing a text search for the
word must and highlight all entries.
By the way i would suggest waiting until you have finished or nearly finished all the documentation before booking the exam. All the documentation, packaging etc took me almost as long as writing the actual code. You don't want to leave yourself short of time.