Be sure that any Java reference book you choose includes JavaSE 5 (also known as JavaSE 1.5) and/or JavaSE 6 (also known as JavaSE 1.6).
Please feel free to recommend your favorite books to your instructor for inclusion in this list.
Java Software Solutions, 5th or 6th Editions, Lewis & Loftus
Addison-Wesley Publishing, ISBNs: 0321409493 (5th) or 0321532058 (6th)
Java Concepts, 5th or 6th Editions, Cay Horstmann
Wiley Publishing, ISBNs: 0470105550(5th) or 0470509473 (6th)
Ivor Horton's Beginning Java 2, JDK 5 Edition, Ivor Horton
Wrox Publishing, ISBN: 0764568744