The goals of Project Jigsaw are reliable dependencies and strong encapsulation, but what does that mean precisely? This session explains the process of module resolution in JDK 9 and shows how it avoids errors relative to the class path in JDK 8. It also explores the double-edged sword of modular accessibility, where the ability to hide a module’s internals must be balanced against the needs of frameworks that perform reflection. Prepare for a deep dive into module graphs, class loaders, unnamed modules, and the once and future king, setAccessible. Mark Reinhold is Chief Architect of the Java Platform Group at Oracle. His past contributions to the platform include character-stream readers and writers, reference objects, shutdown hooks, the NIO high-performance I/O APIs, library generification, and service loaders. Mark was the lead engineer for the JDK 1.2 and 5.0 releases, the JCP specification lead for Java SE 6, and both the project and specification lead for JDK 7 (Java SE 7) and JDK 8 (Java SE 8). He currently leads the JDK 9 and Jigsaw projects in the OpenJDK Community, where he also serves on the Governing Board. Mark holds a Ph.D. in computer science from the Massachusetts Institute of Technology. [VNH-0402]