virtual threads examples

.github/workflows/build.yml

@@ -0,0 +1,17 @@
+name: build
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+jobs:
+  job-container:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-java@v3
+        with:
+            distribution: 'temurin'
+            java-version: '21'
+      - id: compile-sources
+        run: mvn verify -pl source

.gitignore

@@ -22,3 +22,6 @@
 # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
 hs_err_pid*
 replay_pid*
+
+.idea
+target

.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,2 @@
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.8.7/apache-maven-3.8.7-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.1.1/maven-wrapper-3.1.1.jar

README.md

@@ -1 +1,6 @@
-# java-virtual-threads
+# Java Virtual Threads
+
+![build-status](https://github.com/rsaestrela/java-virtual-threads/workflows/build/badge.svg)
+
+This repository contains a few code samples of the usage of Virtual Threads, a feature described in JEP 444 and released
+in Java 21.

pom.xml

@@ -0,0 +1,26 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>me.estrela</groupId>
+    <artifactId>java-virtual-threads</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>Java Virtual Threads</name>
+    <url>estrela.me</url>
+    <properties>
+        <java.version>21</java.version>
+    </properties>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <configuration>
+                    <source>21</source>
+                    <target>21</target>
+                    <enablePreview>true</enablePreview>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>

src/main/java/me/estrela/jvt/MultiplePlatformThreads.java

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+package me.estrela.jvt;
+
+import java.time.Duration;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static me.estrela.jvt.ThreadUtils.describe;
+
+public class MultiplePlatformThreads {
+
+    public static void main(String[] args) {
+
+        AtomicLong runningThreadsCounter = new AtomicLong();
+
+        long startTime = System.currentTimeMillis();
+
+        for (int i = 1; i <= 5_000; i++) {
+            Thread vThread = Thread.ofPlatform()
+                    .name("platform-thread")
+                    .start(() -> {
+                        runningThreadsCounter.incrementAndGet();
+                        try {
+                            Thread.sleep(Duration.ofMinutes(30));
+                        } catch (InterruptedException e) {
+                            // Let the thread die
+                        }
+                    });
+            System.out.println(describe(vThread));
+            if (i % 100 == 0) {
+                long time = System.currentTimeMillis() - startTime;
+                System.out.printf("%,d threads started, %,d threads running after %,d ms%n", i, runningThreadsCounter.get(), time);
+            }
+        }
+
+    }
+
+}
+

src/main/java/me/estrela/jvt/MultipleVirtualThreads.java

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+package me.estrela.jvt;
+
+import java.time.Duration;
+
+import static me.estrela.jvt.ThreadUtils.describe;
+
+public class MultipleVirtualThreads {
+
+    public static void main(String[] args) {
+        Runnable runnable = () -> {
+            try {
+                Thread.sleep(Duration.ofMinutes(30));
+            } catch (InterruptedException e) {
+                throw new IllegalStateException(e);
+            }
+        };
+        for (int i = 0; i < 100_000_000; i++) {
+            Thread vThread = Thread.ofVirtual()
+                    .name("virtual-thread")
+                    .start(runnable);
+            System.out.println(describe(vThread));
+        }
+
+    }
+
+}

src/main/java/me/estrela/jvt/ThreadUtils.java

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+package me.estrela.jvt;
+
+public final class ThreadUtils {
+
+    public static String describe(Thread thread) {
+        return String.format("Thread %s-%s isVirtual=%s status=%s activeThreads=%s",
+                thread.getName(), thread.threadId(), thread.isVirtual(), thread.getState().name(), Thread.activeCount());
+    }
+
+
+}

src/main/java/me/estrela/jvt/VirtualThreadsExecutors.java

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+package me.estrela.jvt;
+
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+public class VirtualThreadsExecutors {
+
+    public static void main(String[] args) {
+
+        try (ExecutorService executorService = Executors.newVirtualThreadPerTaskExecutor()) {
+            Future<Integer> future = executorService.submit(() -> 1 + 1);
+            Integer result = future.get();
+            System.out.printf("Task completed with result=%s", result);
+        } catch (InterruptedException | ExecutionException e) {
+            throw new IllegalStateException(e);
+        }
+
+    }
+
+}

src/main/java/me/estrela/jvt/VirtualThreadsStarter.java

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+package me.estrela.jvt;
+
+import static me.estrela.jvt.ThreadUtils.describe;
+
+public class VirtualThreadsStarter {
+
+    public static void main(String[] args) throws InterruptedException {
+
+        Thread vThread = Thread.ofVirtual()
+                .name("virtual-thread")
+                .start(() -> System.out.println("Started Virtual Thread!"));
+
+        System.out.printf(describe(vThread));
+
+        vThread.join();
+
+        System.out.printf(describe(vThread));
+
+    }
+
+}