Yesterday I took the 1Z0-819 Exam and failed with a Score of 55% (Passing Score: 68%), but I'm not sad or disappointed, I wasn't just ready yet.
I learned a lot during my preparation and it was one of the toughest Exams I ever tried, so it's not a big deal to fail on the first attempt.
But why did I actually tried it? I learned some Java Basics many Years ago but never used it much. Also my IT Career isn't fully focused on Development, even though that's something I personally enjoy most.
One of my colleagues told me about the 25th anniversary offer from Oracle, were you could get Access to a Java SE Developer OCP Online Training and attend the Exam for 25$. I always wanted to improve my Java Skills, so I thought that would be a great opportunity. But due to the timely limited offer, I just had roughly 4 weeks before I had to take the Exam.
Spoiler: A few weeks, even if you spend many hours every day, are not enough to get from zero to hero in Java and to pass 1Z0-819 ;)
The included Online Training from Oracle wasn't that bad, but wasn't that good either. There were some Hands On Labs but the Guide wasn't provided, so you could only watch the Solution Videos, not perfect but to be fair, it was more or less for free.
I checked out learnjava on reddit and they mentioned https://java-programming.mooc.fi what seem to be very popular learning resource. The University of Helsinki provides two Java Courses, most of the content in written form, with a customized NetBeans IDE Version that includes the Test my Content Plugin.
The cool thing is, you just create an mooc.fi Account, Download the IDE and Login. Afterwards you can work through the Exercises, test them locally and upload them. If your Code is correct and pass all Tests, the Exercise will marked as completed in the Online Course.
Actually that was one of my best learning experiences ever, because you have to solve the exercises on your own but due to the integrated testing, you can always check if you do the things right. During my Exam prep, mooc.fi was the most helpful resource.
In addition the Mock Exams provided by enthuWare were quite nice and very cheap. And before you get confused, it's not about Braindumps, Mock Exams are something different.
During the Exam you have to read and interpret a lot of Code and then choose the right answer(s). So you have to fully understand the Topics and can't just learn Questions and Answers. The Mock Exams can help you to get a feeling how the style of the real exam will be.
For me enthuWare was a good addition to the other resources, also I think it was sometimes harder than the real Exam.
If you prefer learning from a Book, I suggest you take a look at Java OCP 11 Developer Complete Study Guide, it's still usable for the 1Z0-819 Exam. I didn't used it myself, but lot of People recommend it, so I will give it a try next time :)
I definitely plan to give it a second shot end of this Year and overall spent more time programming Java. I'm still very interested in Contributing to the Uyuni Project, were lot of the Codebase is Java, so that might be part my Exam Prep too.