Java 9 to 15 - A brief overview of changes to the language

@rodrigograciano Java 9 to Java 15: A brief review of
recent changes to the language Rodrigo Graciano speakerdeck.com/graciano

@rodrigograciano Did you know? uJava 8 released in March 2014
u85% still uses 8 or older version * uAnyone using Java 9+ in PROD? u https://www.jetbrains.com/lp/devecosystem-2020/java/

@rodrigograciano Release Schedule 8

@rodrigograciano About me u Professional with 10+ years u Principal
Software Engineer - NY u NYJavaSIG Leader u graciano.dev u Twitter: @rodrigograciano

@rodrigograciano What we’ll see today? Main changes after Java 8
Not all? 7 versions – Java 15 – September 2020 100+ JEP’s on Java 9 alone

@rodrigograciano Java 9 9 September 2017 Initially scheduled to September
2016 - delayed 3 years after Java 8 Huge number of changes – 100+

@rodrigograciano Jigsaw - JPMS u Scheduled to Java 7 u
11 Java Enhancement Proposals (JEP’s) u Aims to reduce packages size u Split the JDK in parts – Modules u More control over packages u Eliminates the “Jar Hell” u Main module (Root) is java.base u It’s Java – 100% backwards compatible 9

@rodrigograciano Garbage First Collector - G1 u Default choice starting
at Java 9 u Substitute Concurrent Mark Swap (CMS) – Stop the world u Smaller pause time u Memory is split in regions - 1-32MB u Goal is to have 2048 regions (Heap) 9

@rodrigograciano Collections – Factory Methods u Reduce the “boilerplate” u
Return Immutable collections u List<Integer> numbers = List.of(1,2,3); u Set<String> cities = Set.of(”New York City", ”Boston”); u Map<String, Integer> m2 = Map.ofEntries( Map.entry("A",1), Map.entry("B",2) ); 9

@rodrigograciano JShell 9 u Easy to use u Useful to
teach Java language u Read-Eval-Print-Loop

@rodrigograciano Outros u Interfaces can now have private methods (static
and non-static) u Reactive Streams API u Improvements to Optional, try-with resources, streams and Javadoc (HTML 5) u HTTP2 9

@rodrigograciano Java 10 10 March 2018 First release using the
new release cadency – Every 6 months Feature Release – It’s not LTS 12 JEP’s

@rodrigograciano Local Variable Type Inference (var) u var is a
variable type u Cannot be a class attribute u No relation with var/val from Scala/Kotlin u String name = “Rodrigo”; u var name = “Rodrigo”; u var myMap = new HashMap(); //Map<Object, Object>() u Must be initialized – var age; //Not valid u var var = “var”; 10

@rodrigograciano Others u Experimental JIT Compiler – Graal Ahead-of-Time (AOT)
u Parallel G1 GC to improve full GC performance u AppCDS to improve start-up time u New API’s to create collections u List.copyOf(), Set.copyOf(), and Map.copyOf() u Stream API can collect data in an immutable collection u toUnmodifiableList(), toUnmodifiableSet(), and toUnmodifiableMap() 10

@rodrigograciano Java 11 11 September 2018 LTS – Next LTS
will be Java 17 Java EE -> Jakarta EE Java EE source code was separated from the repository

@rodrigograciano GC’s u Epsilon GC – no-op collector. Perfect for
benchmarking u Z GC – Experimental low-latency uWorks with all sizes of heaps – From small to Terabytes uPause time must not exceed 10ms 11

@rodrigograciano Outros 11 u Flight Recorder u Single file source
code programs

@rodrigograciano Java 12 12 March 2019 Feature Release Preview Features
Small Release - 8 JEP's

@rodrigograciano Switch Expressions 12

@rodrigograciano Others u Shenandoah GC – Constant pause time -
Experimental u Microbenchmark Suite - based on JMH u Default CDS Archives – Enhance JDK process to generate a CDS archive u Enhance to G1. Automatically return Java heap memory to the operating system when idle 12

@rodrigograciano Java 13 13 September 2019 Feature Release Preview Features
Just 5 JEP's

@rodrigograciano Text Blocks 13 u Before Text Blocks u With
Text Blocks

@rodrigograciano Others u Switch Expression – 2nd preview u Improvements
to ZGC u Dynamic CDS archives u Reimplement the Legacy Socket API 13

@rodrigograciano Java 14 14 March 2020 Feature Release Preview and
Final Features 16 JEP's

@rodrigograciano Records 14

@rodrigograciano Records (2) u Immutable u Reduce the boilerplate 14

@rodrigograciano Records (3) 14

@rodrigograciano Helpful NPE u Clearer NPE messages u Possible to
know which object is null list.get(0).getName().trim(); u Where’s the null object? The list? Name? Cannot invoke "String.trim()" because the return value of "dev.graciano.Pessoa.getName()" is null 14

@rodrigograciano Pattern Matching for instanceOf u Don’t need to explicitly
cast after the instanceOf if (p instanceOf People people) { people.getName(); } 14

@rodrigograciano Others u JFR Streaming u Switch Expression – Final
version u Text Blocks – 2nd Preview u ZGC on Windows and MacOS u Remove Concurrent Market Sweep GC (CMS) 14

@rodrigograciano Java 15 15 September 2020 Feature Release Preview and
Final Features 14 JEP's

@rodrigograciano Sealed Classes u Permits to control who can extends/implements
a classe/interface public abstract sealed class Shape permits Circle, Square, Triangle {…} 15

@rodrigograciano Others u ZGC and Shenandoah not experimental anymore u
Text Blocks not a Preview Feature u Hidden classes u 2nd Preview of Records u 2nd Preview of Pattern Matching for instanceOf 15

@rodrigograciano Java 16 16 March 2021 Feature Release 16 JEPS’s
confirmadas – so far 1 JEP’s planned – so far

@rodrigograciano What’s new? 16 u OpenJDK migrated from Mercurial to
Git (GitHub) u Enhance the ZGC u Vector API u Final version of Records u Final version of Pattern Matching for instanceOf

@rodrigograciano More from Java 10/11 import java.nio.charset.*; public class Unicode
{ public static void main(String... args) { System.out.print(”Have a \uD83C\uDF7A"); System.out.println(" or a \uD83E\uDD64 "); } } 10/11 Slide extracted from https://speakerdeck.com/boyarsky

@rodrigograciano End ugraciano.dev uTwitter: @rodrigograciano

Java 9 to 15 - A brief overview of changes to the language

Java 9 to 15 - A brief overview of changes to the language

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