My OCEJWCD6 preparation took 6 month with mock exams.First off, I prepared with Head First Servlets and JSP, 2nd Edition book.It wasn't enough for my preparation because there are no annotations and other new features added in Servlet 3.0.It completed 70 percent of my preparation.But I needed another study resource for upgrading Servlet 2.4 knowledge to Servlet 3.0.In order for upgrading my knowledge to that I studied from Servlet 3.0 spec.But there are no essential need to study from JSP 2.2 spec because HFS book was enough for the JSP component of OCEJWCD6 exam even though the exam required JSP 2.2.Because there aren't any essentially change between JSP 2.0 to JSP 2.2.And at the same time I was peeking Servlet API from Oracle Java EE6 doc.I did Enthuware's objective-wise test after I ended each section while preparing.And in end of the preparation I did 10 standard mock exams.And I after each object-wise or mock exam test I reviewed all questions one by one including correct and incorrect answers, and got into details of each of ones.My pass score was between range from 75% to 79% on mock exams.And after my final mock exam(after 6 month) I took the real OCEJWCD6 exam(1z0-899) and result was 82% although I wanted to get score over 90 percent, but I didn't able to. ;)
The preparation materials for OCEJWCD6 while preparing, below:
Head First Servlets and JSP, 2nd Edition(I read this book 2 times)
Servlet 3.0 spec
Enthuware OCEJWCD6(1z0-899) mock exams
NOTE: It's important to create labaratory projects while preparing in order for understanding concepts.Without it you can't pass the exam.