OCP Oracle Certified Professional Java SE 11 Developer Practice Tests Exam 1Z0-819 and Upgrade Exam 1Z0-817 by Scott Selikoff Scott Selikoff OCP Oracle Certified Professional Java SE 11 Developer Complete Study Guide Exam 1Z0-815, Exam 1Z0-816 and Exam 1Z0-817 by Jeanne Boyarsky, Scott Selikoff