Project Jigsaw

The primary goals of this Project are to:

• Make the Java SE Platform, and the JDK, more easily scalable
  down to small computing devices;

• Improve the security and maintainability of Java SE Platform Implementations in general, and the JDK in particular;

• Enable improved application performance; and

• Make it easier for developers to construct and maintain libraries
  and large applications, for both the Java SE and EE Platforms.

To achieve these goals we propose to design and implement a standard module system for the Java SE Platform and to apply that system to the Platform itself, and to the JDK. The module system should be powerful enough to modularize the JDK and other large legacy code bases, yet still be approachable by all developers.

Current documents, presentations, code, & builds

• Project Jigsaw @ JavaOne / Devoxx BE 2015 (slides & video)
• JEP 200: The Modular JDK
  • Module summary
• JEP 201: Modular Source Code
• JEP 220: Modular Run-Time Images
• JSR 376: Java Platform Module System
  • Requirements
  • State of the Module System (design overview)
  • Initial draft JLS and JVMS changes
  • Draft API docs
  • Issue summary
• JEP 260: Encapsulate Most Internal APIs
• JEP 261: Module System
• JEP 282: jlink: The Java Linker
• Source code
• Early-access builds and quick start guide

Status

The reorganization of the source code (JEP 201) was merged into JDK 9 build 27, in August 2014.

The restructuring of run-time images to support modules (JEP 220) was merged into JDK 9 build 41, in December 2014.

JSR 376, for the Java Platform Module System, was approved by the JCP Executive Committee in December 2014.

The plan for encapsulating most internal APIs (JEP 260) was posted in August 2015.

The initial version of The State of the Module System, together with JEP 261 and the first early-access builds containing the prototype module system, were published in September 2015.

A list of open issues in the proposed specification was published in March 2016.

Older documents

• Project Jigsaw: Phase Two
• Goals & Requirements (DRAFT 3)

Our current approach is informed by an earlier exploratory phase as well as a broader context and history.

Community

• Mailing lists
  • jigsaw-dev
• Bloggers
  • Alex Buckley
  • Jonathan Gibbons
  • Mark Reinhold
  • Paul Sandoz
• Related Projects
  • Penrose is exploring interoperability between Jigsaw and OSGi

This Project is sponsored by the Compiler Group.