Yes, wait for the next edition of K&B which covers 5.0
I'd look at the objectives and study all the new feature through the
Java Specification. All the questions are taken from the specification.
Also
test the new features out. They are way cool.
Then you can still use the K&B book that is out now for all the objectives that remain from the 1.4 exam.
Test, Test and test with code to see for yourself results. And do as many mocks as you can.
Good Luck.
Mark