Welcome to the Ranch!
There are many different options for studying for the OCJA and OCJP certifications; you can use one or a combination of these:
- Review the exam objectives (I've posted for Java 7)
here (OCJA) and
here (OCJP). Are you familiar with all the topics that are listed?
- Read & ask questions and answers on these forums. They often help programmers understand Java better.
- Obtain a Java certification study guide. There are a number of good ones mentioned around here; the one I see most often is authored by Sierra and Bates (K&B) who are also active members of the community.
- Read Oracle's Java tutorials
here
- Complete at least a few practice exams (these often are bundled with study guides, or can be purchased separately from vendors like Enthuware). Make sure you are satisfied with your marks (note the practice exams are often a bit harder than the real thing)
- Practice, practice, practice. Being able to write and read code quickly is KEY to passing these exams. The exams tend to have lots of Java code and less pure theory. The more practice you do, the more prepared you will be.
You should be able to get both certifications in two months, provided you are willing to work hard.
If I had to guess on workload, I would say 200 hours study time per exam for a complete beginner, 100 hours for a novice and 10-20 hours study for an expert. That's just a guess though, so if someone has a better guess please comment.