Well, it is a big depends. I had some good experience with J2ME and I found the
test to be difficult.
You can learn J2ME pretty quickly. Using Jonathan Knudsen's book, I started coding two days after I started reading. Not that it was the best code, and one that would allow me to pass the exam.
But they key to passing the exam is to understand the specifications and the objectives that map to them.
The key to passing is to study the specifications and to write code to test to see how the specs show up in code, etc.
If you put good time into this then you can pass the exam. If not, watch out.
Mark