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Java 9 sneak peek
The document outlines key features of Java 9, particularly focusing on the new module system designed to break the JDK into smaller modules and enhance application organization. It highlights improvements such as the Java shell (jshell), a new process API, G1 as the default garbage collector, and various APIs for reactive programming and stack manipulation. Additionally, it references documentation and resources for further exploration of these features.
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Java 9 sneak peek
- 1. Java 9 sneakpeek
- 2. Who am I Softwareconsultant (CoffeeCupConsulting) BG JUG board member (http://jug.bg) OpenJDK and Oracle RBDMS enthusiast Twitter: @martin_fmi
- 3. Agenda • Java 9:module system • Networking break • Java 9: the good parts
- 4. Java 9: modulesystem
- 5. Goals • Break themonolith JDK into smaller modules • Provide module system for Java applications java.base java.logging java.xml java.sql
- 6. Supporting work … •JDK 8 compact profiles javac -profile <profile_name> compact 1 compact 2 compact 3
- 7. Module metadata • Providedby module-info.java • Extends the syntax of the Java language • Exposed at runtime via the java.lang.Module class
- 8. Module metadata module application.demo{ requires java.logging; requires banking.server; provides bg.jug.banking.server.applications.BankingApplication with bg.jug.banking.app.demo.DemoApplication; } Module module = object.getClass().getModule();
- 9. Java 9: modulesystemdemo
- 10. Java 9: thegood parts
- 11. Sneak peek • JavaShell (JShell) • New process API • Small language enhancements • G1 as the default garbage collector
- 12. Sneak peek • NewHTTP/2 client • New stack walking API • New reactive programming API • Misc
- 13. Java Shell (JShell) •Provides a read-eval-print-loop (REPL) shell for the Java platform • Provides a playground for the Java language and its supporting APIs • Provided by the jshell tool part of the JDK installation
- 14. New process API •Before Java 9 …. Process p = Runtime.getRuntime().exec("cmd /c notepad"); ProcessBuilder pb = new ProcessBuilder("cmd", "/c", “notepad"); Process p = pb.start();
- 15. New process API •Limited support for process handling up to JDK 9 • Mostly for creation of a process …
- 16. New process API •java.lang.Process extended with new methods • New Java.lang.ProcessHandle class for process management in a streamlike manner onExit() supportsNormalTermination() toHandle() children() descendants() pid() info()
- 17. Small language enhancements •Not really many … (var definitions did not make it in Java 9) • A few very minor enhancements part of project Coin (the most significant being private methods in interfaces)
- 18. G1 GC • Replacesparallel GC as the default GC • A low-pause collector • Sacrifyes higher throughput (… targets to provide better experience for users)
- 19. G1 GC • Theunit of work is a heap region in a generation • Provides new framework for further optimizations • Most other GCs work on generations directly
- 20. G1 GC • Targetsto clear as much garbage as possible • Has larger footprint than parallel GC
- 21. HTTP/2 client • Stillin incubation (although part of release) • Provides support for HTTP 2.0
- 22. Stack walking API •new API for easier manipulation of stack traces • Provided by the java.lang.Stackwalker class
- 23. Reactive programming API •New publish-subscribe API • Provided by the java.util.concurrent.Flow interface
- 24. Misc • New collectionfactory methods Set.of(…) Map.of(…) Map.ofEntries(…) List.of(…)
- 25. Misc • Multirelease JARfiles • Compact strings • Variable handles
- 26. Misc • A numberof TLS enhancements • Javadoc enhancements • A number of others …
- 27. Java 9: thegood partsdemo
- 28. Summary • The newmodule system is beyond doubt the most significant feature of JDK 9 • There are many new APIs in JDK 9 that extend the developer’s toolbox
- 29. References New features inJava 9 https://docs.oracle.com/javase/9/whatsnew/ Project Jigsaw http://openjdk.java.net/projects/jigsaw/ Oracle JDK 9 Documentation Early Access https://docs.oracle.com/javase/9/javase-docs.htm
- 30. References JShell tutorial http://cr.openjdk.java.net/~rfield/tutorial/JShellTut orial.html Java 9Process API: The Shape of Things to Come http://iteratrlearning.com/java/2017/03/12/java9- process-api.html
- 31. References Process API –Java 9 https://blog.oio.de/2016/09/02/process-api-java-9/ JDK 9 early access download http://jdk.java.net/9/ Java 9: The (G1) GC Awakens https://www.slideshare.net/MonicaBeckwith/java-9-the- g1-gc-awakens