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<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Effective Java SE 9-19 APIs & Language features, makes your life easier</title>
<meta name="description" content="A short summary & overview of the new features & the hidden treasures of Java SE 19">
<meta name="author" content="Mohamed Mahmoud Taman">
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<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no, minimal-ui"/>
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<link rel="stylesheet" href="css/reveal.css"/>
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<!-- Code syntax highlighting -->
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<script src="lib/js/html5shiv.js"></script>
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</head>
<body>
<!--
=== Logos ===============================================================================
-->
<div style="position: absolute; top: 5px; z-index: 6; right: 0; margin-right: 10px">
<img src="media/img/logos/O-Groundbreakers-Logo.png" width="220" height="60" alt="Oracle Groundbreakers Ambassador" />
<img src="media/img/logos/Java Champoins.jpeg" width="60" height="60" alt="Java Champions" />
</div>
<div style="position: absolute; top: 5px; z-index: 6; left: 0; margin-left: 10px">
<img src="media/img/logos/Nlogo_white.png" width="200" height="50" alt="Nortal Logo"/>
<!-- <img src="media/img/logos/ananas-logo.svg" alt="Ananas Logo" />-->
<br/>
</div>
<!-- Slides -->
<div class="reveal">
<!-- Any section element inside of this container is displayed as a slide -->
<div class="slides">
<!--
=== Slide 1- Presentation title & about me =================================================
-->
<section>
<!-- Slide 1.1 - Cover page -->
<section>
<div style="width: 80%; margin: 0 auto">
<h3 style="text-align: center;margin: 00px 0 80px 0">Effective <span style="color: orange">Java SE 9</span> through <span style="color: orange">19</span> APIs & Language features, that make your life easier.</h3>
</div>
<div class="profile" style="position: absolute; top: 200px; left: 300px">
<div class="profile-sidebar" style="border-radius: 15px 15px 0 0">
<div class="profile-userpic">
<img data-src="media/img/logos/TamanFace.jpg" class="img-responsive" alt="">
</div>
<div class="profile-usertitle">
<div class="profile-usertitle-name">
Mohamed Taman
</div>
<div class="profile-usertitle-job">
Solutions Architect @Nortal MEA,<br> Java Champion, Belgrade, Serbia.
</div>
</div>
</div>
<div class="profile-content" style="border-radius:0 0 10px 10px">
<table>
<tr>
<td style="text-align: right; vertical-align: middle; padding: 0"><img data-src="media/img/twitter.png" style="background-color: transparent; border-color: transparent; width: 30%;margin: 0px 0px;"/></td>
<td style="text-align: left; vertical-align: middle; padding: 0"><a href="https://twitter.com/_tamanm"> @_tamanm</a></td>
</tr>
</table>
</div>
</div>
</section>
<!-- Slide 1.1.1 - Intro Video -->
<section>
<iframe width="1150" height="650" src="https://www.youtube.com/embed/zg79C7XM1Xs" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
</section>
<!--
=== Slide 1.2 - Me, I, and Myself ===================================================================
-->
<section>
<h3>Me, I, and Myself <img src="media/img/logos/TamanFace.jpg" style="width: 65px; border-radius: 50%"></h3>
<br/>
<div class="container" style="font-size: .70em;">
<ul>
<li class="fragment fade-down"><strong>Chief Solutions Architect</strong><br/>
Works for Nortal Serbia & Consultant @Ananas.rs.<br/> International Speaker & Author.
Egyptian, and lives in Belgrade, Serbia.
<br/><br/>
</li>
<li class="fragment fade-down">
A <strong> Java Champion</strong>, <strong>Oracle ACE</strong>, and <strong>Jakarta EE Ambassador</strong>. Web / Cloud / Spring / Mobile / Big Data / IoT / Blockchain / DevOps, JCP, <u>2013 - 2015</u> Duke Award winner 3 times, <u>2013</u> JCP award winner.<br/><br/>
</li>
</ul>
<table class="fragment fade-down" style="width: 75%; height: 75%">
<tr>
<td style="vertical-align: middle; padding-right: 5"><img data-src="media/img/JavaMag.jpg" style="background-color: transparent; border-color: transparent; width: 400px;margin: 0 0;" alt=""/></td>
<td style="vertical-align: middle; padding-right: 5"><img data-src="media/img/OracleMag.jpg" style="background-color: transparent; border-color: transparent; width: 400px;margin: 0 0;"/></td>
<td style="vertical-align: middle; padding-right: 5"><img data-src="media/img/infoQ.jpg" style="background-color: transparent; border-color: transparent; width: 400px;margin: 0px 0px;"/></td>
<td style="vertical-align: middle; padding-right: 5"><img data-src="media/img/IBM Developer.jpeg" style="background-color: transparent; border-color: transparent; width: 400px;margin: 0px 0px;"/></td>
<td style="vertical-align: middle; padding-right: 5"><img data-src="media/img/B03998_JavaFX 8 Essentials.jpg" style="background-color: transparent; border-color: transparent; width: 600px;margin: 0px 0px;"/></td>
<td style="vertical-align: middle; padding-right: 5"><img data-src="media/img/V06608_low.png" style="background-color: transparent; border-color: transparent; width: 600px;margin: 0px 0px;"/></td>
<td style="vertical-align: middle; padding-right: 5"><img data-src="media/img/V06153_low.png" style="background-color: transparent; border-color: transparent; width: 600px;margin: 0px 0px;"/></td>
</tr>
</table>
</div>
</section>
<!--
=== Slide 1.3 - reach me ============================================================================
-->
<section>
<h3>You can catch me (🤝) <br/><br/><span class="fragment">here 👇</span></h3>
<ul style="width: 90%" class="fragment">
<li><strong>@_tamanm</strong><br/></li>
<li><a href="https://eg.linkedin.com/in/mohamedtaman">https://eg.linkedin.com/in/mohamedtaman</a><br/></li>
<li><a href="https://www.instagram.com/m.m.taman">https://www.instagram.com/m.m.taman</a><br/></li>
<li><a href="https://github.com/mohamed-taman">https://github.com/mohamed-taman</a><br/></li>
<li><a href="https://www.slideshare.net/tamanm">https://www.slideshare.net/tamanm</a><br/></li>
<li><a href="http://tamanmohamed.blogspot.com">http://tamanmohamed.blogspot.com</a><br/></li>
<li><a href="https://www.facebook.com/public/Mohamed-Mahmoud-Taman">https://www.facebook.com/public/Mohamed-Mahmoud-Taman</a><br/></li>
</ul>
<br/><br/>
<div class="fragment fade-right">
Or <em>google</em> 🕵 me <strong>"Mohamed Taman"</strong>
</div>
</section>
</section>
<!--
=== Slide 2- Introduction (Java History) ===================================================
-->
<section>
<h2>Java History 🛣 </h2>
<img style="border-radius: 15px" width="1460" height="500" class="fragment fade-down" src="media/img/JepPerRelease.png" alt="Java history"/>
<p class="x-small fragment">Image source from:
<a href="https://inside.java/2022/09/20/the-arrival-of-java-19/">The arrival of Java 19</a>
</p>
</section>
<!--
=== Slide 3 - Modularity =======================================================
-->
<section>
<!-- Slide 3.1 - Modularity -->
<section>
<h2>Big change (<span style="color: yellow">Modularity</span> 📦 )</h2>
<div class="fragment">
<div data-markdown>
<script type="text/template">
### Jigsaw [JEP 201](http://openjdk.java.net/jeps/201)<!-- .element: class="jep" -->
</script>
</div>
<blockquote>
“ Module bundle together one or more packages, and offer stronger encapsulation than jars. ”
</blockquote>
</div>
<br/>
<ul>
<li class="fragment fade-up">Allow <strong>scaled down runtime JAR</strong> → IoT, Micro-services, Embedded, Cloud.</li>
<li class="fragment fade-up"><strong>Stronger</strong>: In a module: <code>public</code> is no longer public to others.</li>
</ul>
<br/><br/>
<p class="x-small fragment">For more, here is my <strong>tutorial</strong> @IBM Developer:<br/>
<a href="https://developer.ibm.com/technologies/java/tutorials/java-modularity-1/">Java 9+ modularity: The theory and motivations behind modularity.</a>
</p>
</section>
<!-- Slide 3.2 - Features -->
<section>
<h2>Jigsaw project goals</h2>
<h2>🥅</h2>
<ul>
<li class="fragment">Modular JDK</li>
<li class="fragment">Modular Java Source Code</li>
<li class="fragment">Modular Runtime Images</li>
<li class="fragment">Encapsulate Java Internal APIs</li>
<li class="fragment">Java Platform Module System</li>
</ul>
<br/><br/>
<p class="x-small fragment">For more, here is my two <strong>tutorials</strong> @IBM Developer:<br/>
<a href="https://developer.ibm.com/technologies/java/tutorials/java-modularity-2/">Java 9+ modularity: Module basics and rules.</a><br/>
<a href="https://developer.ibm.com/technologies/java/tutorials/java-modularity-2/">Java 9+ modularity: How to design packages and create modules, Part 1, and 2.</a>
</p>
</section>
<!-- Slide 3.2 - migration tools -->
<section>
<h2>Tools 🧰 for ease of code migrations</h2>
<ul>
<li class="fragment">List built-in modules: <code>java --list-modules</code></li>
<li class="fragment">Find dependencies: <code>jdeps -jdkinternals app.jar</code></li>
<li class="fragment">Find deprecations: <code>jdeprscan app.jar</code></li>
</ul>
<br/><br/>
<p class="x-small fragment">For more, here is my <strong>tutorial</strong> @IBM Developer:<br/>
<a href="https://developer.ibm.com/technologies/java/tutorials/java-modularity-5/">Java 9+ modularity: The difficulties and pitfalls of migrating from Java 8 to Java 9+.</a>
</p>
</section>
</section>
<!--
=== Slide 4 - 6 month release cadence (More productivity) ===================================
-->
<section>
<!-- Slide 4.1 - 6 month release cadence -->
<section>
<h1>The New Six Month Release Cadence and LTS<br/>
<span class="fragment"><strong>🏎</strong></span>
</h1>
</section>
<!-- Slide 4.2 - LTS -->
<section>
<br/>
<h2>LTS 🎗 (Long-Term-Support)</h2>
<p>
Each 2 years we will have an LTS Release.
</p>
</section>
<!-- Slide 4.3 - Java SE 11 Vacuum Cleaner -->
<section>
<h1><span style="color: orange">Java SE 11</span>, is the <br/><br/><span class="fragment" style="font-size:120%">🧹</span><br/><span class="fragment">for Java jungle...</span></h1>
</section>
<!-- Slide 4.4 - Is Java Still Free -->
<!--
<section>
<h2>What is behind the new licensing model of Oracle Java?</h2>
<p>Oracle licensed Java to be commercial starting from Java 8.</p>
<br/> <br/>
<h3 class="fragment">Is <em>Java Still Free</em> of charge?</h3>
<br/>
<div class="fragment">
<h3>Yes it is 💃🕺</h3>
👉 <a href="https://medium.com/@javachampions/java-is-still-free-2-0-0-6b9aa8d6d244">Java is Still Free 2.0.3</a>
</div>
</section>
-->
</section>
<!--
=== Slide 5 - First time preview language feature (Why) =======================================
-->
<section>
<h1>For the first time, <span style="color: orange">Java 12</span></h1>
<div class="fragment">
<h3>introduces a preview language feature</h3>
<h1> <strong>🤔</strong></h1>
</div>
</section>
<!--
=== Slide 6 - Agenda ==========================================================================
-->
<section>
<h1>Agenda</h1>
<ol>
<li class="fragment">What is new?</li>
<li class="fragment">Explore new language features.</li>
<li class="fragment">Explore most of new & Improved APIs.</li>
<li class="fragment">Farewell to APIs has gone forever.</li>
</ol>
</section>
<!--
=== Slide 7 - No more JRE =====================================================================
-->
<section>
<section>
<h1>No more <em>JRE</em> available out there! 😱 </h1>
<ul>
<li class="fragment">JRE installation package is gone, since <span style="color: orange">Java SE 11</span>.</li>
<li class="fragment"><code>jlink</code> tool is here, to generate our custom JRE.</li>
</ul>
</section>
<!-- Slide 7.1 - What is jlink -->
<section>
<h2>What is <code>jlink</code> ?</h2>
<div class="fragment">
<p style=" text-align: left; margin-left:130px"><strong>Linker</strong></p>
<blockquote>
<code>jlink</code> can be used to link a set of modules, along with their transitive dependences,
to create a custom modular run-time image.
</blockquote>
</div>
</section>
</section>
<!--
=== Slide 8 - Learning tools ==================================================================
-->
<section>
<section>
<h1>New learning 👩🏼🏫 tool added to the stack.</h1>
</section>
<!-- Slide 8.1 - JShell -->
<section>
<h3>Java Shell REPL tool: <code>jshell</code> - <span class="small" style="color: orange">Java 9</span></h3>
<div data-markdown style="width: 75%; margin: 0 auto">
<script type="text/template">
````
👻 mohamed_taman:~$ jshell
| Welcome to JShell -- Version 12
| For an introduction type: /help intro
jshell> 3 + 4 * 7
$1 ==> 31
jshell> int add(int a, int b) {
...> return a+b;
...> }
| created method add(int,int)
jshell> add(25, $1)
$3 ==> 56
````
<!-- .element: class="small" -->
Get an overview with `/help` and `/help shortcuts`
<!-- .element: class="x-small" -->
</script>
</div>
<br/>
<p class="x-small fragment">For more, here is my two <strong>tutorials</strong> @IBM Developer:<br/>
<a href="https://developer.ibm.com/tutorials/java-theory-and-practice-4/">Java theory and practice: Interactive Java programming (REPL) with JShell 12, Part 1, and 2.</a>
</p>
</section>
<!-- Slide 8.2 - Old Days -->
<section>
<h2>Running <code>.java</code> old days</h2>
<div data-markdown style="width: 75%; margin: 0 auto">
<script type="text/template">
#### We have a program like this:
````
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello Java 🧡 Developers");
}
}
````
<!-- .element: class="small" -->
- Should be compiled to have `.class`
- Then run `.class` with java
<!-- .element: class="small" -->
````
mohamed_taman$ javac HelloWorld.java
mohamed_taman$ java HelloWorld
Hello Java 🧡 Developers
````
<!-- .element: class="small" -->
</script>
</div>
</section>
<!-- Slide 8.3 - Launch single-file -->
<section>
<h2>Run <code>.java</code> with <code>Java</code><span class="fragment" style="color: orange"> - Java 11</span></h2>
<div class="fragment" data-markdown style="width: 80%; margin: 0 auto">
<script type="text/template">
### Launch Single-File Source-Code Programs [JEP 330](http://openjdk.java.net/jeps/330)<!-- .element: class="jep" -->
##### And now just only run it like this:
````
mohamed_taman$ java HelloWorld.java
Hello Java 🧡 Developers
````
</script>
</div>
<br/>
<p class="x-small fragment">For more, here is my <strong>tutorial</strong> @IBM Developer:<br/>
<a href="https://developer.ibm.com/tutorials/java-theory-and-practice-2/">Java theory and practice: Run single-file source code programs without compilation.</a>
</p>
</section>
</section>
<!--
=== Slide 9 - New Language features ===========================================================
-->
<section>
<section>
<h1><span style="color: orange">Java SE</span> language features<br/><br/> 🎉🎊</h1>
</section>
<!-- Slide 9.1 - var type -->
<section>
<h2>New <code>var</code> type - <span style="color: orange">Java 10</span></h2>
<div class="fragment" data-markdown style="width: 80%; margin: 0 auto">
<script type="text/template">
#### Local-Variable Type Inference [JEP 286](http://openjdk.java.net/jeps/286)<!-- .element: class="jep" -->
````
jshell> var name = "Mohamed Taman"
name ==> "Mohamed Taman"
jshell> var lastName = name.substring(8)
lastName ==> "Taman"
jshell> lastName.getClass().getTypeName()
$3 ==> "java.lang.String"
jshell> var list = List.of(1, 2, 3, 4, 5, 6, 7);
...> var stream = list.stream();
...> stream.filter(x -> x % 2 == 0).forEach(System.out::println)
list ==> [1, 2, 3, 4, 5, 6, 7]
stream ==> java.util.stream.ReferencePipeline$Head@531d72ca
2
4
6
````
<!-- .element: class="small" -->
</script>
</div>
<p class="x-small fragment">For more, here is my <strong>tutorial</strong> @InfoQ:<br/>
<a href="https://www.infoq.com/articles/java-10-var-type">Explore the New Java 10 “var” Type: An Introduction and Hands-on Tutorial.</a>
</p>
</section>
<!-- Slide 9.2 - var for lambda parameters. -->
<section>
<h3>Local-variable (<code>var</code>) Syntax for Lambda Parameters - <span style="color: orange">Java 11</span></h3>
<pre class="fragment"><code>(String a, String b) -> a.concat(b)</code></pre>
<pre class="fragment"><code>( a, b) -> a.concat(b)</code></pre>
<pre class="fragment"><code>(var a, var b) -> a.concat(b)</code></pre>
<div class="fragment">
Because annotations needs a type
<pre><code>(@Nullable var a, @Nonnull var b) -> a.concat(b)</code></pre>
</div>
</section>
<!-- Slide 9.3 - Shell scripting with Java: Shebang files -->
<section>
<h2>Shell scripting with Java: Shebang files - <span style="color: orange">Java 11</span></h2>
<div class="fragment" data-markdown style="width: 80%; margin: 0 auto">
<script type="text/template">
##### The source code is:
````
#!/usr/bin/java --source 11
import java.nio.file.*;
public class DirectoryLister {
public static void main(String[] args) throws Exception {
var dirName = ".";
if ( args == null || args.length < 1 ){
System.err.println("Listing the current directory...");
} else {
dirName = args[0];
}
Files.walk(Paths.get(dirName)).forEach(out::println);
}}
````
<!-- .element: class="small" -->
</script>
</div>
</section>
<!-- Slide 9.3.1 - Run Shebang files -->
<section>
<h3>Run Java Shebang file</h3>
<div style="text-align: left; width: 80%; margin: 0 auto">
<p class="small">Save this code in a file named <code>dirlist</code> <em>without any extension</em> and then mark it as <strong>executable</strong>:</p>
<pre><code>mohamed_taman:code$ chmod +x dirlist</code></pre>
</div>
<div class="fragment" data-markdown style="width: 80%; margin: 0 auto">
<script type="text/template">
###### Run it as the following:
Part of: Launch Single-File Source-Code Programs [JEP 330](http://openjdk.java.net/jeps/330)<!-- .element: class="jep" -->
<!-- .element: class="x-small" -->
````
mohamed_taman:code$ ./dirlist
Listing the current directory...
.
./PalindromeChecker.java
./greater
./UsersHttpClient.java
./HelloWorld.java
./Greater.java
./dirlist
````
<!-- .element: class="small" -->
</script>
</div>
</section>
<!-- Slide 9.5 - The new, standardized HTTP Client module -->
<section>
<h2>HTTP & WebSocket Client module</h2>
<h5>The evolution of <code>HttpClient</code> and <code>WebSocket</code> API</h5>
<br/>
<ul class="x-small">
<li class="fragment">The latest <code>HttpClient</code> and <code>WebSocket</code> APIs originally shipped with <span style="color: orange">JDK 9</span> under the Java Enhancement Proposal <span class="jep">JEP 110</span> as part of an incubator module named <code>jdk.incubator.httpclient</code>.<br/><br/></li>
<li class="fragment">They were re-incubated again in <span style="color: orange">JDK 10</span>, but finally became standardized in a module named <code>java.net.http</code> and brought into the mainstream in <span style="color: orange">JDK 11</span> under <span class="jep">JEP 321</span>.<br/><br/></li>
<li class="fragment">This API provides a high-level client interface to HTTP (<em>versions 1.1 and 2</em>) and low-level client interfaces for the WebSocket API: <code>HttpClient</code>, <code>HttpRequest</code>, <code>HttpResponse</code>, and <code>WebSocket</code>.</li>
</ul>
</section>
<!-- Slide 9.5.1 - The new HTTP Client module -->
<section>
<h2>HTTP Client module</h2>
<h4>Demonstrating how all three APIs work together</h4>
<pre class="fragment" style="width: 80%; margin: 0 auto">
<code>var client = HttpClient.newHttpClient();
var request = HttpRequest.newBuilder()
.uri(create("https://postman-echo.com/get/"))
.build();
client.sendAsync(request, ofString())
.thenApply(HttpResponse::body)
.thenAccept(out::println)
.join(); </code></pre>
<p class="x-small fragment">For more, here is my <strong>tutorial</strong> @IBM Developer:<br/>
<a href="https://developer.ibm.com/tutorials/java-theory-and-practice-3/">Java theory and practice: Explore the new Java SE 11 HTTP Client and WebSocket APIs.</a>
</p>
</section>
<!-- Slide 9.5.2 - The new, WebSocket -->
<section>
<h2>WebSocket Client module</h2>
<div class="fragment">
<p class="small" style="text-align: left; margin-left: 10%">First implement the <code>WebSocket.Listener</code> interface:</p>
<pre class="small" style="width: 70%; margin: 0 auto">
<code>public final class EchoListener implements WebSocket.Listener {
@Override
public void onOpen(WebSocket webSocket) {
logger.info("CONNECTED");
....
}
....
} </code></pre>
</div>
<div class="container fragment">
<p class="small" style="text-align: left; margin-left: 10%">use an <code>HttpClient</code> to create a <code>WebSocket</code></p>
<pre class="small" style="width: 70%; margin: 0 auto">
<code>WebSocket webSocket = httpClient.newWebSocketBuilder()
.buildAsync(URI.create("ws://demos.kaazing.com/echo"),
new EchoListener(executor)).join();
webSocket.sendClose(WebSocket.NORMAL_CLOSURE, "ok").thenRun(() -> logger.info("Sent close")).join();</code>
</pre>
</div>
</section>
<!-- Slide 9.6 - switch statement -->
<section>
<h2>Old Switch statement</h2>
<pre class="x-small" style="width: 55%"><code>jshell> String getRomanNumber(int value){
String romanValue = "";
switch(value){
case 0: romanValue = "nulla";
break;
case 1: romanValue = "I";
break;
case 2: romanValue = "II";
break;
case 3: romanValue = "III";
break;
case 4: romanValue = "IV";
break;
case 5: romanValue = "V";
break;
case 6: romanValue = "VI";
break;
case 7: romanValue = "VII";
break;
case 8: romanValue = "VIII";
break;
case 9: romanValue = "IX";
break;
case 10: romanValue = "X";
break;
default: System.out.printf("Out of range value: %d %n", value);
romanValue = "N/A";
break;
}
return romanValue;
}</code></pre>
</section>
<!-- Slide 9.6.1 - New switch statement -->
<section>
<h3>New Switch statement - <span style="color: orange">Java 12</span></h3>
<pre class="fragment small" style="width: 70%"><code>mohamed_taman:~$ jshell --enable-preview</code></pre>
<pre class="small fragment" style="width: 70%"><code>String getRomanNumber(int value){
String romanValue = "";
switch(value){
case 0 -> romanValue = "nulla";
case 1 -> romanValue = "I";
case 2 -> romanValue = "II";
case 3 -> romanValue = "III";
case 4 -> romanValue = "IV";
case 5 -> romanValue = "V";
case 6 -> romanValue = "VI";
case 7 -> romanValue = "VII";
case 8 -> romanValue = "VIII";
case 9 -> romanValue = "IX";
case 10 -> romanValue = "X";
default -> {
System.out.printf("Out of range value: %d %n", value);
romanValue = "N/A";
}
}
return romanValue;
}</code></pre>
</section>
<!-- Slide 9.6.2 - new switch expression -->
<section>
<h3>New Switch expression</h3>
<pre class="small" style="width: 70%"><code>String getRomanNumber(int value){
return switch(value){
case 0 -> "nulla";
case 1 -> "I";
case 2 -> "II";
case 3 -> "III";
case 4 -> "IV";
case 5 -> "V";
case 6 -> "VI";
case 7 -> "VII";
case 8 -> "VIII";
case 9 -> "IX";
case 10 -> "X";
default -> throw new IllegalStateException("Out of range value: " + value);
};
}</code></pre>
</section>
<!-- Slide 9.6.3 - Multi-case switch statement -->
<section>
<h3>Multiple comma-separated labels in a single switch case</h3>
<div style="width: 105%; margin: 0 auto;">
<div class="twocol fragment fade-right">
<pre class="small" style="width: 95%"><code>jshell> String getOddOrEvenNumber(int value){
String kind = "N/A";
switch(value){
case 0: kind = "Zero"; break;
case 1:
case 3:
case 5:
case 7:
case 9: kind = "Odd"; break;
case 2:
case 4:
case 6:
case 8:
case 10: kind = "Even"; break;
default: System.out.printf("Out of range: %d %n", value);
}
return kind;
}</code></pre>
</div>
<div class="twocol fragment fade-down">
<pre class="small" style="width: 99%"><code>jshell> var kind = switch(value){
...> case 0 -> "Zero";
...> case 1, 3, 5, 7, 9 -> "Odd";
...> case 2, 4, 6, 8, 10 -> "Even";
...> default -> throw new IllegalStateException("Out of range: " + value);
...> };</code></pre>
</br>
<p class="fragment" style="font-size: 80%" >For more, here is my <strong>tutorial</strong> @IBM Developer:<br/>
<a href="https://developer.ibm.com/tutorials/java-theory-and-practice-6/">Effective use of the new switch statement and expression in Java SE 12.</a>
</p>
</div>
</div>
</section>
<!-- Slide 9.6.4 - New Java 13 yield keyword -->
<section>
<h3><strong>Yield</strong> and switch expression - <span style="color: orange">Java 13</span></h3>
<div style="width: 105%; margin: 0 auto;">
<div class="twocol fragment fade-right">
<pre class="small" style="width: 95%"><code>jshell>var value = 3
value ==> 3
jshell> String kind = switch(value){
...> case 0: break "Zero";
...> case 1, 3, 5, 7, 9: break "Odd";
...> case 2, 4, 6, 8, 10: break "Even";
...> default: throw new Exception("Out of range: " + value);};
kind ==> "Odd"</code></pre>
<div class="fragment fade-right">
<p>Dropping <strong style="text-decoration: line-through;">break</strong> & introducing <strong>yield</strong></p>
<pre class="small" style="width: 95%"><code>jshell> value = 10
value ==> 10
jshell> String kind = switch(value){
...> case 0: yield "Zero";
...> case 1, 3, 5, 7, 9: yield "Odd";
...> case 2, 4, 6, 8, 10: yield "Even";
...> default: throw new Exception("Out of range: " + value);};
kind ==> "Even"</code></pre>
</div>
</div>
<div class="twocol fragment fade-down">
<p style="font-size: 80%">This is why <strong>community feedback</strong> is important, & the <strong>preview feature</strong> is great for such changes. </br></br>
- In <span style="color: orange">Java 14</span> switch expressions is standardized.
</p>
<img class="fragment fade-in" src="media/img/image_04.gif" style="width: 80%; border-color: transparent;"></img>
</div>
</div>
</section>
<!-- Slide 9.7 - text block -->
<section>
<h2>New <code>Text Blocks</code> (Preview) - <span style="color: orange">Java 13</span></h2>
<div>
<h3 class="fragment">History:</h3>
<ul class="small">
<li class="fragment fade-right">This feature intended to be introduced in <span style="color: orange">Java 12</span> as <span style="text-decoration: line-through; color: red">Raw String Literals (Preview)</span>.</li>
<li class="fragment fade-right">Re-introduced as <strong>Text Blocks (Preview)</strong> in <span style="color: orange">Java 13</span>.</li>
<li class="fragment fade-right">Continue as <strong>Text Blocks (Second Preview)</strong> in <span style="color: orange">Java 14</span>.</li>
<li class="fragment fade-right">And it is <strong>Text Blocks (Final)</strong> in <span style="color: orange">Java 15</span>.</li>
</ul>
<div data-markdown style="width: 80%; margin: 0 auto" class="fragment fade-down">
<script type="text/template">
[JEP 326](http://openjdk.java.net/jeps/326)<!-- .element: class="jep" -->
[JEP 355](http://openjdk.java.net/jeps/355)<!-- .element: class="jep" -->
[JEP 368](http://openjdk.java.net/jeps/368)<!-- .element: class="jep" -->
[JEP 378](http://openjdk.java.net/jeps/378)<!-- .element: class="jep" -->
</script>
</div>
</div>
<div style="width: 105%; margin: 0 auto;">
<div class="twocol fragment fade-right">
<pre class="small"><code>var html = "\n" +
"<html>\n" +
" <body>\n" +
" <p>Hello, world</p>\n" +
" </body>\n" +
"</html>\n";
</code></pre>
</div>
<div class="twocol fragment fade-left">
<pre class="small"><code>var html = """
<html>
<body>
<p>Hello, world</p>
</body>
</html>
""";</code></pre>
</div>
</div>
</section>
<!-- Slide 9.8 - Pattern matching -->
<section>
<h3>Pattern Matching for <strong>instanceof</strong> (Preview) - <span style="color: orange">Java 14</span>, and (second preview) <span style="color: orange">Java 15</span></h3>
<a class="jep" style="color: white" href="http://openjdk.java.net/jeps/305">JEP 305</a>
<a class="jep" style="color: white" href="http://openjdk.java.net/jeps/375">JEP 375</a>
<div style="width: 105%; margin: 0 auto;">
<div class="twocol">
<pre class="small fragment fade-down" style="width: 95%"><code>//Old Days
if (obj instanceof String) {
// Need to declare & cast again the object
String str = (String) obj;
.. str.contains(..) ..
}else{
.. str = ....
}</code></pre>
<pre class="small fragment fade-right" style="width: 95%"><code>//Java 14 Onwards
if (obj instanceof String str) {
// No need to declare str object again with casting
.. str.contains(..) ..
} else {
.. str....
}</code></pre>
</div>
<div class="twocol fragment fade-down">
<pre class="small" style="width: 99%"><code>//More complex examples
if (obj instanceof String str && str.length() > 5) { .. str.contains(..) .. }</code></pre>
<br/>
<p>The use of pattern matching in <strong>instanceof</strong> should dramatically reduce the overall number of explicit casts in Java programs.</p>
</div>
</div>
</section>
<!-- Slide 9.9 - Records -->
<section>
<h3>Records (1st Preview) <span style="color: orange">Java 14</span>, (2nd Preview) <span style="color: orange">Java 15</span>, & (Standardized) <span style="color: orange">Java 16</span></h3>
<a class="jep" style="color: white" href="http://openjdk.java.net/jeps/359">JEP 359</a>
<a class="jep" style="color: white" href="http://openjdk.java.net/jeps/384">JEP 384</a>
<a class="jep" style="color: white" href="http://openjdk.java.net/jeps/395">JEP 395</a>
<div class="x-small fragment fade-down" style="width: 90%; text-align: left; margin-left: 5%">We need to write a lot of low-value, repetitive code to write a simple data carrier class responsibly: <code>constructors</code>, <code>accessors</code>, <code>equals()</code>, <code>hashCode()</code>, <code>toString()</code>, etc. To avoid this repetitive code, Java introduced records. In the Second preview it works well with Sealed Classes, and could be declared locally.</div>
<pre class="small fragment fade-left"><code>final class Point {
public final int x;
public final int y;
public Point(int x, int y) {
this.x = x;
this.y = y;
}
// state-based implementations of equals, hashCode, toString
// nothing else</code></pre>
<pre class="small fragment fade-left"><code>record Point(int x, int y) { }</code></pre>
</section>
<!-- Slide 9.10 - NPE enhancements -->
<section>
<h3>Helpful NullPointerExceptions - <span style="color: orange">Java 14</span></h3>
<a class="jep" style="color: white" href="http://openjdk.java.net/jeps/358">JEP 358</a>
<div class="x-small fragment fade-down" style="width: 90%; text-align: left; margin-left: 5%">Before Java 14, the JVM will print out the method, filename, and line number that caused the NPE:</div>
<pre class="small fragment fade-left"><code>a.i = 99;
Exception in thread "main" java.lang.NullPointerException
at Prog.main(Prog.java:5)</code></pre>
<div class="x-small fragment fade-down" style="width: 90%; text-align: left; margin-left: 5%">In Java 14 - Suppose an NPE occurs in this code:</div>
<pre class="small fragment fade-left"><code>a.b.c.i = 99;</code></pre>
<pre class="small fragment fade-left"><code>Exception in thread "main" java.lang.NullPointerException:
Cannot read field 'c' because 'a.b' is null.
at Prog.main(Prog.java:5)</code></pre>
</section>
<!-- Slide 9.9 - Sealed Classes -->
<section>
<h3>Sealed Classes (Preview) - <span style="color: orange">Java 15</span></h3>
<a class="jep" style="color: white" href="http://openjdk.java.net/jeps/360">JEP 360</a>
<div class="x-small fragment fade-down" style="width: 90%; text-align: left; margin-left: 5%">It allow the author of a class or interface to control which code is responsible for implementing it. And it provide a more declarative way than access modifiers to restrict the use of a superclass.</div>
<pre class="small fragment fade-left"><code>package com.example.geometry;
public sealed class Shape
permits Circle, Rectangle, Square {...}
public final class Circle extends Shape {...}
public sealed class Rectangle extends Shape
permits TransparentRectangle, FilledRectangle {...}
public final class TransparentRectangle extends Rectangle {...}
public final class FilledRectangle extends Rectangle {...}
public non-sealed class Square extends Shape {...}</code></pre>
</section>
<!-- Slide 9.10 - Records & Sealed Classes -->
<section>
<h3>Records (2nd Preview) - <span style="color: orange">Java 15</span></h3>
<a class="jep" style="color: white" href="http://openjdk.java.net/jeps/359">JEP 359</a>
<div class="x-small fragment fade-down" style="width: 90%; text-align: left; margin-left: 5%">It allow you to define a sealed interface and implement them on your records</div>
<pre class="small fragment fade-left"><code>sealed interface Car permits BMW, Audi { ... }
record BMW(int price) implements Car { ... }
record Audi(int price, String model) implements Car { ... }</code></pre>
<div class="x-small fragment fade-down" style="width: 90%; text-align: left; margin-left: 5%">Local records are a great boon for Java developers who would earlier have to create helper records</div>
<pre class="small fragment fade-left"><code>List<Merchant> findTopMerchants(List<Merchant> merchants, int month) {
// Local record
record MerchantSales(Merchant merchant, double sales) {}
return merchants.stream()
.map(merchant -> new MerchantSales(merchant, computeSales(merchant, month)))
.sorted((m1, m2) -> Double.compare(m2.sales(), m1.sales()))
.map(MerchantSales::merchant)
.toList();
}</code></pre>
</section>
</section>
<!--
=== Slide 10 - New language APIs ==============================================================
-->
<section>
<!-- Slide 10.1 - New language APIs -->
<section>
<p style="font-size: 300%">👓</p>
<h1 class="fragment"> New language APIs</h1>
</section>
<!-- Slide 10.2.1 - String class new enhancements 1 -->
<section>
<h2><code>String</code> class new enhancements</h2>
<ul>
<li class="fragment"><code>String repeat(int)</code> - <span style="color: orange">Java 11</span>
<pre class="fragment" style="width: 100%"><code>jshell> "no ".repeat(14).trim().concat(", Batman!")
$1 ==> "no no no no no no no no no no no no no no, Batman!</code></pre>
</li>
<li class="fragment"><code>boolean isBlank()</code> - <span style="color: orange">Java 11</span>
<pre class="small" style="width: 100%"><code>jshell>var blankText = " "
blankText ==> " "
jshell>blankText.trim().length() == 0
$2 ==> true
jshell>blankText.isBlank()
$3 ==> true</code></pre>
</li>
</ul>
</section>
<!-- Slide 10.2.2 - String class new enhancements 2 -->
<section>
<ul>
<li><code>String stripLeading()</code> - <span style="color: orange">Java 11</span></li>
<li><code>String stripTrailing()</code> - <span style="color: orange">Java 11</span></li>
<li><code>String strip()</code> - <span style="color: orange">Java 11</span>
<pre class="fragment small" style="width: 100%"><code>jshell>var textWithSpaces = "\n \t Text \u2005"
textWithSpaces ==> "\n \t Text "
jshell>textWithSpaces.trim()
$4 ==> "Text "
jshell>textWithSpaces.strip()
$5 ==> "Text"</code></pre>
</li>
<li class="fragment"><code>Stream lines()</code> - <span style="color: orange">Java 11</span>
<pre class="small" style="width: 100%"><code>jshell> "\nOne\nTwo\nThree\nFour".lines().forEach(System.out::println)
One
Two
Three
Four</code></pre>
</li>
</ul>
</section>
<!-- Slide 10.2.3 - String class new enhancements 3 -->
<section>
<ul>
<li><code>String indent(int)</code> - <span style="color: orange">Java 12</span>
<pre class="fragment small" style="width: 100%"><code>jshell> "\nOne\nTwo\nThree\nFour".indent(5).indent(-2).lines().forEach(System.out::println)
... One
... Two
... Three
... Four</code></pre>
</li>
<li class="fragment"><code>String transform(Function)</code> - <span style="color: orange">Java 12</span>
<pre class="small" style="width: 100%"><code>jshell> var text = "Text with*out *some* *asterisks"
text ==> "Text wi*th *some* * asterisks"
jshell> text.transform(String::toUpperCase)
...> .transform(s -> s.replaceAll("\\*", ""))
...> .transform(s -> s.split(" "))
$1 ==> String[4] { "TEXT", "WITHOUT", "SOME", "ASTERISKS" }
</code></pre>
</li>
</ul>
<p class="x-small fragment">For more, here is my <strong>tutorial</strong> @IBM Developer:<br/>
<a href="https://developer.ibm.com/tutorials/java-theory-and-practice-1/">Java theory and practice: Explore new Java SE 11 and 12 APIs and language features.</a>
</p>
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<h4>As part of: Text Blocks (Preview) - <span style="color: orange">Java 13</span>
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<li><code>String formatted(Object[])</code>
<pre class="small fragment fade-right" style="width: 100%"><code>jshell> "Hello %s!".formatted("World")
| Warning:
| formatted(java.lang.Object...) in java.lang.String has been deprecated and marked for removal
| "Hello %s!".formatted("World")
| ^-------------------^
$11 ==> "Hello World!"</code></pre>
</li>