Note: If you know other links which would be useful here or notice some that are obsolete, please contact me.

I passed both Programmer and Developer for 1.2 Java Platform exams in 2002, so most materials here are related to that time period. The first one is more like a memory test, but the Developer exam, where you must submit almost full scale client/server application, was an interesting one. The challenging part was that you always had to keep in mind that your customer (examiner) will be deprived the live technical support on how to use your application!

The general Certification path described at the Sun's web site at : JAVA[tm] TECHNOLOGY PROFESSIONAL DEVELOPMENT PATH

The Programmer exam:

First of all check the original resources at the Sun web site: SUN CERTIFIED PROGRAMMER FOR THE JAVA[tm] 2 PLATFORM It contains free ePracice questions along with the paid solutions.

www.javaranch.com. It has links to numerous mock exams, both free and commercial, including the detailed description of the quality of those exams, simple warm-up questions in the game form, general resources and much-much more.

Mock exam at the Chris Grindstaff site: very good mock exam. I would definitely advise to go through it and make sure that you perfectly understand provided explanations of correct/wrong answers. It includes 100 questions, times you (1h30 min) and the questions are represented in a small window where you have to scroll: which simulates real environment quite well: at the exam I was struggling not with the questions, but 15" blinking screen and necessity to scroll back and force especially on the big pieces of Thread related code. So be ready.

The Developer exam:

I passed this exam fully based on my hands-on experience, but here is the link to the Sun web link describing that exam. SUN CERTIFIED DEVELOPER FOR THE JAVA[tm] 2 PLATFORM. I can tell that if you spend most of your work time designing real life client/server applications it would be easier for you to pass this exam than the Programmer exam. As I mentioned I enjoyed doing that assignment and it took me less time than preparation for the programmer exam, where you have to impersonate yourself with the "walking compiler". On the other hand if you don't have real life experience it would be quite hard, I would say almost impossible to pass this exam because it requires knowledge and usage of sound industry practice, patterns and standards.

The Architect exam:

I plan to go through that exam at one point, but now I just simply don't have time as it consists of three elements: a knowledge-based multiple choice exam, an assignment and essay exam. So if to put it into the reasonable time framework you should probable allocate somewhere between 1 - 4 month depending on you real work/family schedule. Sun web link describing exam: SUN CERTIFIED ENTERPRISE ARCHITECT FOR JAVA[tm] 2 PLATFORM, ENTERPRISE[tm] EDITION.
This is a link to an interesting article "Get the inside track on J2EE architect certification" written by the By Humphrey Sheil, who passed the exam and now performs the role of the examiner. The same page contains links to some architect exam resources.

"Sun Certified Enterprise Architect for J2EE Technology Study Guide" book co-authored by Mark Cade, who, if I understood correctly from the above mentioned article, was one of the exam designers. I checked the table of content and it seems as a reasonable and quite comprehensive guide. So when I decide to go through the exam I plan to buy this book.

www.Javaranch.com web site, which I found very useful while preparing for the programmer exam. It contains some architect exam resources, including links to books, some mock exams and educational articles.