Java 9 / Jigsaw - LJC / VJUG session (hackday session)
11 likes3,855 views
Modularisation in Java 9 splits the Java language and JDK/JRE into modules. This includes modularising the OpenJDK source code and runtime images to improve structure, reduce dependencies, and allow for smaller custom runtimes using jlink. The Java Platform Module System (JSR 376) introduced modules that define dependencies and exported/opened packages, allowing Java code and the JDK to be modularized. Hands-on sessions demonstrated creating modules, using jlink to build custom runtimes, and migrating non-modular code to Java 9.
Java 9 / Jigsaw - LJC / VJUG session (hackday session)
- 1. Java 9 / Jigsaw Modularisation & more
- 2. Presenters Simon Maple @sjmaple Mani Sarkar @theNeomatrix369 Hendrik Ebbers @hendrikebbers
- 4. Agenda - Session 1: Introduction - What is meant by Modularisation in Java 9? - Session 2: JLink - Lunch break: lunch + 10/15 minute optional session - Fundamentals and background - JSRs / JEPs playing a role - Modularisation of OpenJDK sources (JEP 201 and related JEPs) - Modularisation of Runtime Images (JEP 220 and related JEPs) - Modularisation of Java Packages and Application Packaging (JEP 275 and related JEPs) - Feature distribution - Why modularisation? - So many more topics to cover! - Visualise your dependencies! - Session 3: Migrating non-modular app to Java 9 or JShell - Feedback - Contribution - Resources
- 5. How to share your (live) feedback with us? Discussion/technical corner, share your thoughts, code snippets, issues, feedback with us while you code away... https://goo.gl/oytFzX We have left a few issues for you to find, investigate, solve, report to us or the OpenJDK / JDK9 team
- 6. Setup Is everyone setup, and ready to go? https://git.io/v9UJ8 You have this link via email / meetup message!
- 7. Session 1: Introduction: Java 9 modularisation 15 minutes
- 8. What is meant by Modularisation in Java 9? JDK module java.base package java.io class Console ... package java.lang class String ... module java.logging package java.util.logging class FileHandler class LogManager ... module java.sql package java.sql class Connection class SqlData ... Java, the language: split into modules modules... packages... classes...
- 9. What is meant by Modularisation in Java 9? java.base java.sql other modules... java.logging Java, the language: dependency graph java.xml implicit implicit explicit (requires) explicit (requires) implicit JDK
- 10. What is meant by Modularisation in Java 9? Java, the language: dependency graph java.base java.sql other modules... java.logging java.xml implicit implicit explicit (requires) explicit (requires) implicit JDK Our Java applications explicit (requires) explicit implicit
- 11. What is meant by Modularisation in Java 9? Pre-Java 9 Java 9/Jigsaw src/main/java package a.b.c class p class q package m.n.o class s class t src/main/java module a.b.c package a.b.c class p class q module m.n.o package m.n.o class s class t Structure of a typical Java app. containing packages... Create your own modules containing packages, classes...
- 12. What is meant by Modularisation in Java 9? Typical package structure Modules contain packages Credits to Paul Bakker & Sander Mak package books.api.entities classes package bookstore.api.service What is looks like from the file system?
- 13. What is meant by Modularisation in Java 9? Typical package structure Modules contain packages Credits to Paul Bakker & Sander Mak contains module visibility (readability) & dependency info module books.api contains package books.api.entities package books.api.service modules What is looks like from the file system?
- 14. What is meant by Modularisation in Java 9? module com.abc { requires com.abc.pqr; requires transitive com.xyz.abc; exports com.abc.def.alpha; exports com.abc.pqr.beta to com.ijk.mno, com.lmn.stu; uses java.network.Driver; provides java.sql.Driver with com.mno.def.Driver; } module definition defines dependencies of module, to modules com.abc.pqr & com.xyz.abc transitive keyword defines implicit dependency module name How is module dependencies are defined in Java 9? module-info.java
- 15. What is meant by Modularisation in Java 9? module com.abc { requires com.abc.pqr; requires transitive com.xyz.abc; exports com.abc.def.alpha; exports com.abc.pqr.beta to com.ijk.mno, com.lmn.stu; uses java.network.Driver; provides java.sql.Driver with com.mno.def.Driver; } module definition make all & only public types in specified packages available to other modules How is module dependencies are defined in Java 9? module name … or make available to specified modules module-info.java
- 16. What is meant by Modularisation in Java 9? module com.abc { requires com.abc.pqr; requires transitive com.xyz.abc; exports com.abc.def.alpha; exports com.abc.pqr.beta to com.ijk.mno, com.lmn.stu; uses java.network.Driver; provides java.sql.Driver with com.mno.def.Driver; } module-info.java module definition this module publishes a service provider this module uses a service provider published by another module module name How is module dependencies are defined in Java 9?
- 17. Session 1: Hands-on: Java 9 modularisation 60 minutes https://github.com/AdoptOpenJDK/jdk9-jigsaw/tree/master/session-1-jigsaw-intro
- 18. Session 1: feedback 15 minutes https://goo.gl/oytFzX
- 19. Lunch break 60 minutes Short 10/15 minutes covering intro/background/fundamentals (talk while having a bite of food and drink)
- 20. What is meant by Modularisation in Java 9? A bit of fundamentals and background before we get to the answer
- 21. What is meant by Modularisation in Java 9? modularisation Pre-Java 9 Java 9 Anomalies OpenJDK& JDK
- 22. What is meant by Modularisation in Java 9? How we perceive the JDK/JRE from a developer’s / end-user’s perspective? JDK or JRE IBM Other vendors Oracle download Create Client Apps distribute Client Apps + bundle JRE
- 23. What is meant by Modularisation in Java 9? How the maintainers of Java perceive it? Distribute built apps + bundle JDK IBM Other vendors Oracle build downloadOpenJDK JDK
- 24. What is meant by Modularisation in Java 9? Modularisation of OpenJDK sources (JEP 201 and related JEPs) Binary compatible JDK re-organise rebuild OpenJDK source Refactored OpenJDK source Repository JDK re-organise Improved layout of source folders in the JDK repository
- 25. What is meant by Modularisation in Java 9? Modularisation of Runtime Images (JEP 220 and related JEPs) Binary compatible JDK re-organise rebuild Runtime JDK Optimised (modular) JDK Runtime Traditional Runtime JDK Image re-organise A more compact Runtime JDK Image
- 26. What is meant by Modularisation in Java 9? Modularisation of Java Packages and Application Packaging (JEP 275 and related JEPs) Modular Java 9 application + custom JDK compiles creates Modularised JDK Runtime Modular Java 9 source JLink Smaller JDK footprint Java 9 applicationcompiles creates Modularised JDK Runtime Non-modular Java 9 source Binary compatible creates
- 27. What is meant by Modularisation in Java 9? JSR 376: Java Platform Module System played the primary role http://openjdk.java.net/projects/jigsaw/spec/
- 28. What is meant by Modularisation in Java 9? JEPs that lead to all the new features in Java 9 (including Jigsaw): - 200: The Modular JDK - 201: Modular Source Code - 220: Modular Run-Time Images (depends on JEP 162) - 260: Encapsulate Most Internal APIs (no dependencies) - 261: Module System (dependens on JEP 220, related to JEP 238) - 282: jlink: The Java Linker (replaces implementation of JEP 220) - 275: Modular Java Application Packaging - 222: jshell: The Java Shell (Read-Eval-Print Loop) - 193: Variable Handles - 110: HTTP 2 Client - 238: Multi-Release JAR Files - 158: Unified JVM Logging - G1 related JEPs (3) - JEPs related to a number of security improvements - JEPs related to a number of platform improvements - >>> Many, many more JEPs, see the Java 9 JEPs list for further details <<<
- 29. What is meant by Modularisation in Java 9? JDK 9& Jigsaw feature distribution ... Other JDK 9 features Jigsaw ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...
- 30. Why Modularisation in Java 9? But, why?
- 31. It’s been worked on for about a decade: - Encapsulation (hiding away what’s not intended or necessary for public use) - JDK internal APIs (sun.misc.unsafe, security, etc…) - Our APIs - Decluttering of code bases (loose coupling & high cohesion) - OpenJDK sources - JDK sources - Our Java App sources (post migration and refactoring) - Customised runtime JDK (smaller footprint) - Highly desirable for IoT, arduino/embedded devices, etc… - Improve distribution and runtime performance - OSGi has it, why not in native Java? - Any more? Why Modularisation in Java 9?
- 32. Not everything can be covered but let’s find out about these topics: - open module - open package - named and unnamed modules - difference between classpath and module path - automatic module names - kill switch (remove Jigsaw restrictions) - a CLI flag passed to java: java --permit-illegal-access … - Jlink CLI option: --launcher - and many more topics... So many things to cover!
- 34. Session 2: Introduction: JLink 10 minutes
- 35. Session 2: Introduction: JLink Create a package distributable, that runs on any platform, but needs a platform specific JDK JDK (javac) Your App packages & classes Your App package (distributable) JVM, the Platform Java, the language (packages & classes) Any JRE/JDK compiles creates Pre-Java 9 depends on (needs), to run
- 36. Session 2: Introduction: JLink JDK modules JLink JVM, the Platform Java, the language (JDK modules) Your App modules Create standalone distributable (smaller footprint), that runs on a specific platform Your App modules JDK compiles creates Java 9
- 37. Session 2: Hands-on: JLink 40 minutes https://github.com/AdoptOpenJDK/jdk9-jigsaw/tree/master/session-2-jlink
- 38. Session 2: feedback 10 minutes https://goo.gl/oytFzX
- 39. Session 3: Introduction: Migration or JShell 15 minutes
- 40. Session 3: Introduction: Migration or JShell Hendrik Ebbers @hendrikebbers Over to Hendrik
- 41. Session 3 hands-on: Migration or JShell 60 minutes https://github.com/AdoptOpenJDK/jdk9-jigsaw/tree/master/session-3-jshell
- 42. Session 3 & overall: feedback 15-30 minutes https://goo.gl/oytFzX
- 43. Contribute Don’t like something or like something a lot, want to contribute to make things better? https://adoptopenjdk.gitbooks.io/adoptopenjdk-getting-started-kit/content/en/how-to-navigate/how_to_contribute_to_adopt_openjdk_and_openjdk.html
- 44. Feedback We value your feedback, make Java better with your constructive feedback https://adoptopenjdk.gitbooks.io/adoptopenjdk-getting-started-kit/content/en/feedback.htm l
- 45. Resources Want to know about the other features of Java 9: https://github.com/AdoptOpenJDK/jdk9-jigsaw/blob/master/Java-9-Resources.md
- 46. Thank you to all Thank you for your continued support 9 @virtualJug @ljcjug @hackthetower @adoptopenjdk @openjdk @jcp_org @java