Hie Wali,
People will tell you varying experiences about the exam.When I took it, I also found it to be a lot harder than most of the mocks floating around, I remember Ajith posted something to the same effect.On the contrary even a lot more will tell you they find the real exam a lot easier than the mocks, actually I remember someone went to the extent that he felt cheated by Sun when he took the exam and found it too easy!!!
My advice is that dont compare the grades you get in mocks to reflect what you will get on the exam.I said this when I just took the exam that it is quite easy for one to master a mock exam after retaking it several times,so the best way to use the mocks should be to expose your weak areas so that you can concentrate on those and be better prepared.Do not try to memorise answers when you get a mock question wrong, rather use it to guide on which material to study further.
Dont look for the hardest mock, it will only mislead you, because the exam is hard in its own way.If you are able to get around 90% in the general mocks,and you feel confident with
Core Java, go for it, you will make it.Just take the exam objectives, and go through them one by one and convince yourself that you have complete understanding of the material
as put by the objectives.Believe me, the exam does not trick you and Sun are quite faithful to go by their objectives.
And hey, this person who has scared you has passed hasn't he?, so if he has done it, there is no way you shouldn't do it,
if you follow the right steps .
Good luck,
Herbert.