I work with Java a long time, but recently I returned my focus to the certification.
Some tips for all, based on my experience:
It took from me about 2 months, 3h day. Note: some days I studied 1h and in another I studied 10h..
First off all, read all the book KB and do the exercises. It took me about 5 weeks.
Second: review the book and do the exercises again Do not use the answers that you have did. 2 weeks
And the last: do mock exams until get 80%, I did 4 mocks, its took 3h each to do and more 2h to review all questions (both answered correctly and incorrectly) (1 week)
I sugest you to take notes with "post-its", this will help you to memorize somethings and help you to keep focused. Place post-its in your car, pc, bedroom.. etc! Write a question in the front and the answers in the back.
And the additional: I am not fluent in English, I attempted to take notes in post-its of keywords that I see on mocks and in the book, and it worked! You can try this too if you need.
and Good luck!
It is a pleasure sharing my experience with all of you