Can I simply use this book and refer to the J2SE 5 API to do the assignment ?
You certainly can do that - it is a great book.
Also are there any other books that you would recommend ?
Well, mine of course . The book that Terry and I worked on is an updated version of the one that you are currently using: we have updated the assignment and discussions it uses to reflect changes in the SCJD assignments, and we discuss in detail the changes to the J2SE API in JDK 5 that are applicable to the assignment.