as for what my preparation included ? ( not in any order )
1) Khalid Mughal's book . an ecxellent resource for a starter and for a quick reference later on.
2) Velumurugans notes.
3) Mock exams from Maha Anna's list, Java Ranch list etc.
4) Dan Chisholm's exams. I did all the exams from this site. Great exam's and free !!!
5) Did Marcus green's & Jiris' exams.
Thats about it.
I believe I screwed in Threads, there were lot of questions in threads and lengthy code one's. I wouldnt say difficult but definitely tricky.
Some of the control flow questions were lengthy too.
I didn't had enough time to complete the whole test , partly may be because I spent lot of time in reading and analysing those lengthy code but their answers were simple in the end. I had to go thru the whole code most of the time because most of the questions had "Compile fails " as the possible options.
Some of the questions were very very simple.
Its not that bad though. just do your preparation right. write lots code. give lot of mock exams.
Good Luck