The OCPJP8 exam, also known as Oracle Certified Professional Java Programmer, is a professional level exam and the second part of Java 8 certification.
The exam code for OCPJP8 is 1Z0-809, and it is considered to be more stringent than the associate level exam.
While there are newer Java certifications available, the Java 8 certification is still the easiest path to become a certified Java developer.
If you are preparing for the OCPJP8 exam, here are some recommended books to help you with your preparation.