Thanks to all the javaranch community for your support.
In order to prepare for the exam I studied the K&B book and integrated with the oracle tutorial available here.
Big credit also to Enthuware software which, other than being low priced and delivering super quality questions, is also a great learning tool per se.
I strongly reccomend this software in order to be prepared for the exam and at the same time understand the concept as all the question have detailed explanation very well written. (if you do not understand something you can clarify in the forum which will promtly reply usually within max 24 hour).
I also used nikojava.wordpress.com/.../free-scjp-mock-exams/ that for generics and multi-threading topics is very good. (even if it's related to OCPJP 6)
That's all super happy about it, thanks again to everybody especially to Jeanne Boyarsky, Henry Wong, Paul Clapham and last but not least super Paul Anilprem.