Frontiers of Access Controls - Modules and Nestmates in Java

Explore the frontiers of access controls in Java, focusing on modules and nestmates. Dive into the implementation of access control mechanisms added in Jigsaw for both the JVM and core libraries. Learn about the evolving nestmate proposal (JEP 181) and its potential applications for Java nested classes, sealed classes, and dynamic class addition to packages or nests. Understand the concepts of modules, module descriptors, reliable configuration, and deployment strategies. Examine type access checks, bytecode resolution, and JVM method resolution in Java SE 9. Investigate the proposed changes for nestmates, including use cases for nested class trampolines and anonymous class definition. Analyze invokespecial examples and restrictions, and discuss open issues related to nestmates.

Syllabus

Intro
What is a Module?
How do you define a Module? - Module Descriptor
Reliable Configuration: The module graph
Where do you deploy Modules?
Class Path vs. Module Path
Backward Compatibility: Unnamed Module
Type Access Check: Java SE 9 Target Type T is accessible to Type S if
Bytecode Resolution and Access Controls - Sample Bytecodes that resolve symbolic Type References
JVM Method Resolution: Access Checks
Java SE Library Access Checking
Nestmates Use Case: Nested Class Trampolines
Proposed JVMS 55.4.4 Access Control Changes
Member Access Check: Proposal for Nestmates
Nestmates Use Case: Unsafe.defineAnonymousClass
Exploring Evolution: Not based on unsafe
Nestmates Access: Implementation changes required
Invokespecial Examples: , super, local I
JVMS 9 Invokespecial Restrictions (non.)
Nestmates Open Issues