If you are looking for an SCJP 1.5 Complete Reference, maybe you better think twice. SCJP 5.0: Tiger version (or Exam CX-310-055) has already come out and many people are already training to update their Sun certification to this platform standard. If you want to train for the most up to date exam, train for the SCJP 5.0: Tiger iteration you will be better off in the end.
It is important to learn the latest developments in the Sun field of knowledge rather than be bogged down with comparisons with previous knowledge taught. If you feel it is fun to make comparisons between exam iterations, well, that is your choice. But newcomers to accreditation are better off just sticking to one standard first and learning that well.
Novices should not try to absorb Java Certification materials right off the bat. Rather, they should look for material that gives the most basic information first. In fact, those with absolutely no computer programming knowledge are swimming out of their depth. These students should learn basic computer programming first before attempting Java coding.
If you feel you are ready for Java, then learn the theory, learn the code, and learn how both work together to create an application. And do this often, to get the hang of it. Pretty soon, it will become instinctive.
If you know other people who want to get Java accreditation, and you trust their capabilities in learning, then you should study with those people if you can. Learning is magnified by sharing your insights with peers, rather than sticking to self-study alone. But self-study can also bring satisfactory results.