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Merge pull request #3 from ibrahimatay/java-24
A few Java 24 examples
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‎README.md

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## Specifications & Practices
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* [Java 24](java-24/) (March, 2025)
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* [JEP 488](java-24/src/main/java/com/ibrahimatay/JEP488PrimitiveTypesInPatternsInstanceofAndSwitch.java): Primitive Types in Patterns, instanceof, and switch
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* [JEP 495](java-24/src/main/java/com/ibrahimatay/JEP495SimpleSourceFilesAndInstanceMainMethods.java): Simple Source Files and Instance Main Methods
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* [JEP 485](java-24/src/main/java/com/ibrahimatay/JEP485StreamGatherers.java): Stream Gatherers
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* [JEP 487](java-24/src/main/java/com/ibrahimatay/JEP487ScopedValues.java): Scoped Values
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* [Java 23](java-23/) (September, 2024)
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* [JEP 455](java-23/src/main/java/com/ibrahimatay/JEP455PrimitiveTypesInPatternsInstanceofAndSwitch.java): Primitive Types in Patterns, instanceof, and switch
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* [JEP 467](java-23/src/main/java/com/ibrahimatay/JEP467MarkdownDocumentationComments.java): Markdown Documentation Comments

‎java-24/pom.xml

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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<parent>
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<groupId>com.ibrahimatay</groupId>
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<artifactId>Java-Features</artifactId>
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<version>1.0-SNAPSHOT</version>
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</parent>
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<artifactId>java-24</artifactId>
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<properties>
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<maven.compiler.source>24</maven.compiler.source>
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<maven.compiler.target>24</maven.compiler.target>
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<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
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</properties>
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<build>
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<plugins>
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<plugin>
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<groupId>org.apache.maven.plugins</groupId>
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<artifactId>maven-compiler-plugin</artifactId>
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<configuration>
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<source>24</source>
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<target>24</target>
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<compilerArgs>--enable-preview</compilerArgs>
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</configuration>
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</plugin>
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</plugins>
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</build>
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</project>

‎java-24/src/main/java/JEP485StreamGatherers.java

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import java.util.concurrent.ThreadLocalRandom;
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import java.util.stream.Gatherers;
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import java.util.stream.Stream;
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public class JEP485StreamGatherers {
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public static void main(String[] args) {
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// Stream Gatherers (JEP 485)
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// https://openjdk.java.net/jeps/485
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// Custom Intermediate Operation distinctBy
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/*
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Stream.of("foo", "bar", "baz", "quux")
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.gather(Gatherers.distinctBy(String::length))
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.toList();
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*/
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// Creating Fixed-size Windows
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/*
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Stream.iterate(0, i -> i + 1)
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.gather(Gatherers.windowFixed(3))
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.limit(2)
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.toList();
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*/
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// Parallel Processing with selectOne
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/*
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Stream.generate(() -> ThreadLocalRandom.current().nextInt())
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.limit(1000)
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.parallel()
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.gather(Gatherers.selectOne(Math::max))
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.findFirst();
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*/
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}
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}

‎java-24/src/main/java/JEP487ScopedValues.java

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import static java.lang.ScopedValue.where;
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public class JEP487ScopedValues {
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// Define a scoped value
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private static final ScopedValue<String> USER_NAME = ScopedValue.newInstance();
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public static void main(String[] args) {
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// JEP 487: Scoped Values (Fourth Preview)
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// https://openjdk.org/jeps/487
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where(USER_NAME, "John").run(() -> {
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System.out.println("User: " + USER_NAME.get());
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subMethod();
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});
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}
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public static void subMethod() {
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// Access scoped value within a sub-method
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System.out.println("User in subMethod: " + USER_NAME.get());
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}
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}

‎java-24/src/main/java/JEP488PrimitiveTypesInPatternsInstanceofAndSwitch.java

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import java.util.Map;
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public class JEP488PrimitiveTypesInPatternsInstanceofAndSwitch {
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public static void main(String[] args) {
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// JEP 488: Primitive Types in Patterns, instanceof, and switch (Second Preview)
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// https://openjdk.org/jeps/488
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// Primitive Types ile Pattern Matching
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Object obj = 42;
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if (obj instanceof int i) {
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System.out.printf("Primitive int value: %1$s\n", i);
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}
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// Switch for Primitive Type
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System.out.printf("%1$s HTTP status code refers to a %2$s%n", 100, getHTTPCodeDesc(100));
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System.out.printf("%1$s HTTP status code refers to a %2$s%n", 200, getHTTPCodeDesc(200));
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System.out.printf("%1$s HTTP status code refers to a %2$s%n", 403, getHTTPCodeDesc(403));
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System.out.printf("%1$s HTTP status code refers to a %2$s%n", 0, getHTTPCodeDesc(0));
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// Record Patterns with Primitive Types
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JsonValue json = new JsonObject(Map.of(
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"name", new JsonString("Alice"),
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"age", new JsonNumber(28)
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));
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if (json instanceof JsonObject(var map)
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&& map.get("name") instanceof JsonString(var name)
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&& map.get("age") instanceof JsonNumber(var age)) {
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System.out.printf("Name: %s, Age: %.0f%n", name, age);
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}
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}
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// Switch for Primitive Type
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public static String getHTTPCodeDesc(int code){
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return switch(code) {
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case 100 -> "Continue";
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case 200 -> "OK";
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case 301 -> "Moved Permanently";
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case 302 -> "Found";
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case 400 -> "Bad Request";
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case 500 -> "Internal Server Error";
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case 502 -> "Bad Gateway";
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case int i when (i > 100 && i < 200) -> "Informational";
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case int i when (i > 200 && i < 300) -> "Successful";
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case int i when (i > 302 && i < 400) -> "Redirection";
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case int i when (i > 400 && i < 500) -> "Client Error";
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case int i when (i > 502 && i < 600) -> "Server Error";
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default -> "Unknown error";
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};
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}
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}
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interface Human {}
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class Employee implements Human {}
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class Boss implements Human {}
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sealed interface JsonValue permits JsonString, JsonNumber, JsonObject {}
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record JsonString(String value) implements JsonValue {}
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record JsonNumber(double value) implements JsonValue {}
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record JsonObject(Map<String, JsonValue> map) implements JsonValue {}

‎java-24/src/main/java/JEP495SimpleSourceFilesAndInstanceMainMethods.java

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// JEP 495: Simple Source Files and Instance Main Methods (Fourth Preview)
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// https://openjdk.org/jeps/495
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public void main() {
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System.out.printf("%1$s + %2$s = %3$s", 1,2, sum(1,2));
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}
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int sum(int x, int y) {
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return x+y;
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}

‎pom.xml

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<packaging>pom</packaging>
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<version>1.0-SNAPSHOT</version>
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<modules>
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<module>java-5</module>
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<module>java-6</module>
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<module>java-7</module>
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<module>java-8</module>
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<module>java-9</module>
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<module>java-10</module>
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<module>java-12</module>
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<module>java-23</module>
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<module>java-14</module>
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<module>java-24</module>
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</modules>
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<properties>

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