I study CS at Open University (UK), my experience with Java (and programming in general) consists mainly of studying this module and writing few very simple programs. I still have 2 years before I get my degree and I'm stuck in a dumb job so I decided to get certified to increase my chances of getting a job interview. I tried the free test from Whizlabs first, I think I scored around 50% so I knew I had to to get prepared. Bought Boyarsky & Selikoff book and went through it, tried couple of tests from the book and few from Whizlabs, I think I never scored more than 70% as I could not stay focused for 2.5 hours. I'm sure I understood all the concepts but often missed some details. Still, I was convinced that I can pass the exam so I gave it a go and got 74%. Not a very good score but didn't want to spend too much time studying, wanted to get back to coding and building stuff Thinking about doing OCP now but it might be wise to wait till I get some more programming experience, I think it makes more sense. Btw, we used Java 7 at the uni and I was little bit scared of lambdas but the book explains it in a really good way, I'm getting used to it now and even use streams in my little projects, they make the code so much easier to read
If you next challenge if the Java 809 OCP certification then you may want to go over some of the stories found OCP Wall Of Fame https://coderanch.com/wiki/659976/OCPJP-Wall-Fame.
By reading some of these stories you can see how others have prepared and what resources they used. This could save some time, money and frustration.
“The strongest of all warriors are these two — Time and Patience.” ― Leo Tolstoy, War and Peace