It's difficult to prepare for an exam using a book that covers a different version. This is especially true regarding
Java 1.4 and 5.0, because these exams are significantly different.
If you have the book for 5.0, I really think
you should consider the 5.0 exam. There is a lot of new material on the 5.0 exam that you will be seeing in the book (and will use in practice), so you may as well get certification credit for knowing it. Also, there is some material on the 1.4 exam that is
not covered in the 5.0 exam (for example, bit manipulation and the Math class), so if you're taking the 1.4 exam you will need to cover those topics elsewhere.
For a high-level idea of what's different, see
SCJP FAQ: How is the 1.5 exam different than the 1.4 exam?