I've been using
java for about 4 years now and finally decided to go for the
SCJP. Picked up the Sun Certified Programmer & Developer for Java 2 Study Guide (Exam 310-035 & 310-027) book by Kathy Sierra and Bert Bates and study for about a month. Used the whizlab exam simulator for about 2 weeks before the exam, which seemed to be a bit harder than the real thing but did do a fairly decent job of preparing for the exam in general and pointing out the objectives I need to work on. Overall, I wouldn't say that taking the exam has made me a better Java programmer, but it has made me more aware of the various little intricacies that I usually depended on the compiler to slap me upside the head when I violated.