Life Beyond Java 8 - Speaker Deck

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https://blog.jetbrains.com/idea/2020/09/a-picture-of-java-in-2020/ Java 8 remains the most popular version. It is used by 75% of professional developers who use Java as their primary language.

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https://www.infoq.com/news/2020/03/new-relic-jvm-report/ https://snyk.io/wp-content/uploads/jvm_2020.pdf “The majority of JVMs (over 85%) are running on Java 8”

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Releases, Updates, Licensing & Support

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We have two types of releases

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We have two types of releases Releases and LTS (Long Term Support) releases

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$$$ $$$

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$$$ $$$

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https://flic.kr/p/8xhk74

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Java 11 Long Term Support (LTS) Release; ~3 years support

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Java 15 Current release; be prepared to upgrade in March 2021

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https://jdk.dev

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IntelliJ IDEA can help you

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Why bother?

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Java 11 Long Term Support (LTS) Release

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JShell

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var

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Convenience Factory Methods for Collections

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Collecting to Unmodifable Collections items.stream() .filter(Objects!::nonNull) .map(Object!::toString) .collect(Collectors.toUnmodifiableList());

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New Methods on Stream API items.stream() .takeWhile(user !-> user.count() < maxCount) .forEach(user !-> position.incrementAndGet());

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Predicate.not()

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New Methods on Optional

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Built in Http Client

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• https://blog.jetbrains.com/idea/2017/10/creating- multi-release-jar-files-in-intellij-idea/ Multi Release Jar Files

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Jigsaw

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Java Module System

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JLink

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Java 15 Current Release

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Switch Expressions

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Switch Expressions https://jb.gg/ij-jdk12

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Text Blocks

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Text Blocks https://jb.gg/ij-jdk13

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Hidden classes

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Hidden classes JEP 371

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A Scalable Low-Latency Garbage Collector

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A Scalable Low-Latency Garbage Collector JEP 377

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Preview Features

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Pattern Matching for instanceof

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Pattern Matching for instanceof https://jb.gg/ij-jdk14

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Records

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Records https://jb.gg/ij-jdk14

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Sealed Types

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Sealed Types https://jb.gg/ij-jdk15

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https://openjdk.java.net/projects/jdk/15/

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The Future

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• JEP 302: Lambda Leftovers (including underscore for param) • JEP 360: Sealed Types (Preview) • JEP draft: Pattern matching for switch (Preview) • Project Amber • Valhalla • Loom • Lots of Garbage Collection improvements Java 16

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• Project Amber • Valhalla • Loom • More Garbage Collection improvements • Proposed New Project: Leyden And in the future?

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The Business Doesn’t Care About Language Features

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Performance

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Use of Memory

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• Java 9: JEP 248: G1 the Default GC • Java 10: JEP 307: Parallel Full GC for G1 • Java 11: JEP 318: Epsilon (Experimental) • Java 11: JEP 333: ZGC (Experimental) Garbage Collection (Java 11)

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• Java 12: More Updates to G1 • Java 14: Deprecate the ParallelScavenge + SerialOld GC Combination • Java 15: ZGC (Production) • Java 15: Shenandoah (Production) Garbage Collection (Java 15)

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Cost

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Cost £$€

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Tips for Migration

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Run on updated JDK

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Run on updated JDK It might “just work”

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Address compiler warnings

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Address compiler warnings …they are there for a reason

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Update your dependencies

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Update your dependencies And add new ones

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Update your build tool

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Update your build tool Updated Maven and Gradle required

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Compile against updated JDK

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Compile against updated JDK …and start using the shiny new features

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https://bit.ly/8-to-11

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In Summary

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Modern Java Can Help You

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Modern Java Can Help You Performance, cost, maintenance…

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There are two upgrade options

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There are two upgrade options To Java 11 (LTS) or to Java 15 (upgrade every 6 months)