Java 11 has a number of new features over Java 8 (var, modules, etc) although that wasn't the only major change. The structure of the exam itself. The Java 11 1Z0-815 exam is generally more difficult than the Java 8 1Z0-808 exam it replaced. Whereas with the 1Z0-808 exam, we covered the basics and left the more complicated stuff for the second exam, this time we had to cover a lot of front this time around. Put simply, the 1Z0-815 exam is about making sure you have a solid foundation in the core Java topics, while the 1Z0-816 is about expanding your knowledge into deeper and broader subjects.