after waiting for 3 horrible weeks I passed the SCJD:
General Considerations (maximum = 100): 100 Documentation (maximum = 70): 70 O-O Design (maximum = 30): 30 GUI (maximum = 40): 24 Locking (maximum = 80): 80 Data store (maximum = 40): 40 Network server (maximum = 40): 40
I never posted anything in this board before, but it helped me: The solution of Andrew Monkhouse for identifying clients when using RMI with a DBMain interface without cookies saved a lot of time. In other points I got the valuable assertion that my thoughts were correct, for example about not implementing the methods delete and create. Thanks!
It worked on my assignment for 17 days (100 - 200 hours): 6 Days designing, 7 days implementing, 3 days for the rest of the documentation and testing.
Notable implementation comments: I did not implement the delete and create methods. I made a very simple GUI without menu or button bar. Usually that pays off as other score reports demonstrate, but I think what they did not like was that I did not even use a file chooser for the database file (just a text field). I used a very simple, very weird locking system I thought up by myself. I did not handle the case that a client holding a lock crashes (or disconnects or whatever) and thus does not unlock and documented this in my choices (why I did this) and in the user manual (what to do in that case). With 138 kB source code (including lots of comments) I kept the program simple and small. I always had the "must"-requirements in mind, designed and programmed closely towards them.
I wrote several much harder programs in the past, some of them are in commercial use. But the database locking was new to me. Though my own weird system has been approved I have to read about the common solutions to such problems.
SCWCD. Btw: It is said that the SCWCD is easier and goes faster than the SCJD. But for me it is the other way round. I expect about 3 - 6 Months learning time for the SCWCD, and writing the SCJD-assignment took only about 17 days. I have to admit however that I don't know anything about what I need for the SCWCD, and for the SCJD I had all the theoretical knowledge and experience to start immediately. Besides for Java web components I did not find a book that I like yet.