Hello Margarita Babkova,
Well, I can give you my own example. I have a full time job, before OCMJD, I almost never did any GUI coding, for OCPJP (
SCJP in my case), I only studied standard synchronization mechanism like wait, notify etc. (not the classes/api from concurrency package - which I used for OCMJD assignment). By the way, I guess you'll be working with a single data file, so you don't have to worry about 'database' (i.e.
JDBC etc.)
I only read the paper by Roberto, put my questions on this forum (and got nice help - especially by Roberto and Roel), and read Monkhouse book. It took me around 2 months to complete everything (assignment submission and essay exam). And yes, I got a descent score (385/400)
Once you follow SDLC properly, the assignment is not really that difficult. One of the most complicated part is - concurrency. No matter what, your application should never enter in the deadlock (in case of deadlock, failure is guaranteed).
I personally believe that 6 months is more than sufficient amount of time for this certification. Of course, if you need any help, you can always get back to this forum.
I hope this helps.
All the best.
On a lighter note, I believe you have a
full time job (not a
fool time job)