RHE stands for Roberts, Heller, and Ernst. They are the authors of a book entitled Complete Java2 Certification. It is a very good book, and I strongly recommend that you get a copy of it. Exam Cram is also very good, but the above book will go more in depth in order to explain the concepts, while Exam Cram will really help you reinforce and review those concepts. I suggest that you use both books. I've been doing just that and I've found that they compliment each other very nicely.
Never trust an airline that limits their passengers to one carry on iguana. Put this tiny ad in your shoe: