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<!doctype html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
<title>Java 17</title>
<link rel="stylesheet" href="../../reveal.js/dist/reset.css">
<link rel="stylesheet" href="../../reveal.js/dist/reveal.css">
<link rel="stylesheet" href="../../reveal.js/dist/theme/black.css" id="theme">
<!-- Theme used for syntax highlighted code -->
<link rel="stylesheet" href="../../reveal.js/plugin/highlight/monokai.css" id="highlight-theme">
</head>
<body>
<div class="reveal">
<div class="slides">
<!-- Slides are separated by newline + three dashes + newline, vertical slides identical but two dashes -->
<section data-markdown data-separator="^\n---\n$" data-separator-vertical="^\n--\n$">
<textarea data-template>
<!-- ## Java 17 -->
## New features in Java 17
--
## Who am I
Joost van Gils
Java Developer
Payments Gladiators
Notes:
* 50 years old, father of 3 sons, Almere
* Java since 2001 (Java 1.3), also Scala + functional programming style
* At AA since November 2022
* Hobbies: tech, music (midi), home automation
---
## A little history
--
## Java almost 27 years old
| version | release date | support ends |
| ------------ |:---------------:| ---------------:|
| 1.0 | 23-01-1996 | ? |
| SE 5 | 29-09-2009 | April 2015 |
| SE 8 (LTS) | 18-03-2014 | December 2030 |
| SE 11 (LTS) | 25-09-2018 | September 2026 |
| SE 17 (LTS) | 14-09-2021 | September 2029 |
Notes:
Oracle. Azul, Red Hat, etc dates differ
--
## Features
| version | features |
| --- |:----------------------------------------:|
| 5 | generics, annotations, enums, autoboxing, vararg, static imports |
| 8 | lambdas, stream API, java.nio (7), default methods |
| 11 | var keyword (10), http client, EE removed |
| 17 | wait for it... |
Notes:
* The unmentioned versions mainly introduced improvements to APIs
* Actually: 17, 16, 15, 14, 13, 12
---
## Records
(Java 16)
Notes:
* Introduced in Java 16
--
```java
public record Point(long x, long y) {
// nothing to see here
}
```
--
* Similar to Lombok's `@Value`
* Implicit
* all-args contructor
* getters for all fields
* `equals` and `hashcode` methods
* `toString` method
* Very efficient on JVM
--
```java
var p = new Point(10, 20);
var q = new Point(10, 20);
```
```java
System.out.println( p );
System.out.println( p.x() );
System.out.println( p.equals(q) );
```
```sh
Point[x=10, y=20]
10
true
```
---
## Pattern matching for instanceOf
(Java 16)
--
Java 11
```java
if (obj instanceof String) {
String s = (String) obj;
System.out.println(s.length());
}
```
Java 17
```java
if (obj instanceof String s) {
System.out.println(s.length());
}
```
---
## Text blocks
(Java 15)
--
Java 11
```java
String html =
"<html>\n" +
" <body>\n" +
" <em>Cool LTS Java 17 Features</em>\n" +
" </body>\n" +
"</html>\n";
```
Java 17
```java
String html = """
<html>
<body>
<em>Cool LTS Java 17 Features</em>
</body>
</html>
""";
```
---
## Helpful NullPointerExceptions
(Java 14)
--
Java 11
```java
var street = customer.getAddress().getStreet();
```
```sh
Exception in thread "main" java.lang.NullPointerException
at com.abnamro/com.abnamro.App.main(App.java:17)
```
--
Java 17
```java
var street = customer.address().street();
```
```sh
Exception in thread "main" java.lang.NullPointerException:
Cannot invoke "com.abnamro.Address.street()" because the
return value of "com.abnamro.Customer.address()" is null
at com.abnamro.Application.main(App.java:21)
```
---
## Switch expression
(Java 14)
--
```java
int numDays = switch(month) {
case JAN, MAR, MAY, JUL, AUG, OCT, DEC -> 31;
case APR, JUN, SEP, NOV -> 30;
case FEB -> {
if (year % 400 == 0) yield 29;
else if (year % 100 == 0) yield 28;
else if (year % 4 == 0) yield 29;
else yield 28; }
};
```
* an *expression*, not a *statement*
* no error-prone fall-through (`break`)
* pattern matching
---
## Sealed classes
(Java 17)
--
```java
public abstract sealed class Animal
permits Dog, Cat {
}
public final class Dog extends Animal {
}
public final class Cat extends Animal {
}
```
--
Useful for
* `switch` without `default` case
* compiler can check exhaustiveness of `if/then/else` statements
* Algebraic data types (with `records`)
---
## Improved streams API
(Java 16)
--
For example, instead of
```java
var list = stream.collect(Collectors.toList())
```
simply do
```java
var list = stream.toList();
```
Beware: `toList()` returns an immutable List
---
## Why (not) use Java 17
--
## Cons
* Requires new skills, also for future maintainers
* Infra might not be up to date (IDE, SonarQube, build agents, live environments)
* Existing projects: not enough benefit to migrate
* Libraries that do not work on a Java 17 JVM
* It might be scary to do things differently
--
## Pros
* Many bug fixes and security improvements
* Premier support for Java 11 ends Sept 2023
* Instant performance boost
Java 17 is about 8.5% faster than Java 11 on G1 GC and 6.5% on parallel GC ([source](https://www.optaplanner.org/blog/2021/09/15/HowMuchFasterIsJava17.html)).
* Spring Boot 3+ requires it
* No need to use new features immediately
* It's fun to use new things!
---
## Java 17 @ ABN AMRO
--
([source: Hitchhiker's Guide](https://confluence.int.abnamro.com/display/GRIDAD/Standard+Programming+Languages))
--
* Use `master-pom` 4.1.0 as parent pom for your project
```xml
<parent>
<groupId>com.abnamro.coesd</groupId>
<artifactId>master-pom</artifactId>
<version>4.1.0</version>
</parent>
```
* Set java source & target to `17` (as 11 is still default)
```xml
<java.source>17</java.source>
<java.target>17</java.target>
```
([source: Hitchhiker's Guide](https://confluence.int.abnamro.com/pages/viewpage.action?pageId=435333723))
--
* Set version to `1.17` in Pita's `java-maven` template
```yml
resources:
repositories:
- repository: templates
type: git
name: GRD0001045/pita-pipeline-templates
stages:
- stage: CI
jobs:
- template: flows/java-maven.yml@templates
parameters:
java_version: '1.17'
```
--
ABN AMRO and Azure support it completely
It makes sense to use it for new projects on Azure
---
## Thank you!
joost.van.gils@nl.abnamro.com
</textarea>
</section>
</div>
</div>
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