I just took the OCAJP7 exam for the first time and passed it scoring exactly 90%. I felt compelled to share my story with using Enthuware that help me get there. I had just finished reading cover-to-cover a Manning publication called "OCA Java SE 7 Programmer I Certification Guide" written by Mala Gupta. I would call myself a semi-seasoned Java programmer starting out with JDK 1.1 and remember using the first version of Jbuilder when it came out.
Anyway, Java has always been something I dabbled with on the side and decided I want to make it more a focus of my career. While reading Gupta's book, I realized how much I didn't know that I didn't know about Java -- BTW, I highly recommend this book! When done with it, I took the mock test at the end of the book and just barely passed it. On top of that, I timed myself and it took me 3 hours and realized I need more practice (last test I took was over 15 years ago). I found a reference to the Enthuware mock exams on the Ranch (thank you JavaRanch) and spent what I would say was the best $10 I have ever spent. I shouldn't say this but they should be charging more but then it was a discounted price. I hardly ever speak up on forums but I just felt I needed to for others that may benefit from my experience.
Here are some things about the exams I particularly wanted to point out.
Don't be discouraged if you don't pass them all as they are more difficult than the real exam. I took all 6 of them and didn't pass any of them. My scores:
T1: 60%
T2: 69%
T3: 63%
T4: 68%
T5: 68%
T6: 74%
Real Exam: 90%
VERY IMPORTANT: Do yourself a huge favor and go back over ALL questions and read through the well written explanations on not only the questions you missed but also the ones you got right. You might be surprised that you got a few questions right but only by a lucky guess or you thought it was because of X when it was really because of Y. Not to mention that the authors of these tests include some extra goodness in the explanation of the answers that gives you more overall depth of the problem. BTW, they used an awesome approach to this by repeating the entire question along with the answers and explanation, which really helps.
Also, for those questions that you either got wrong or guessed right, if there is a discussion about it, click the weblink to it and read what was said. I found a couple of them had some more insight, which certainly doesn't hurt.
Don't be discouraged if you don't complete them in the time allotted. I ran out of time an average of about 30 minutes. When I took the real exam, I finished with 10 minutes to spare and used that time to go over a couple that I had marked to take a second look at. I know one should skip and go back but I worried that I would run out of time so on a couple that I stalled on, I marked what I felt (guessed) and then marked it to come back to. That way if I ran out of time, I at least had attempted it. Not sure if that technique works for most people but it did for me.
Now off to the next level. I found ONE "Alpha" book that I purchased and downloaded last night published with Apress called "Oracle Certified Professional Java SE 7 Programmer Exams 1Z0-804 and 1Z0-805" by Ganesh and Sharma and of course I spent another $10 on the Enthuware exams that I know I will want to use for this
If you are traveling down this road. Good luck to you and remember, if it were easy it wouldn't feel as good when you succeed