Configuration options for virtual threads (on JDK 21)

VirtualThreadDelegate built on JDK 21 for multi-release jar.
Includes dedicated VirtualThreadTaskExecutor as lean option.
Includes setVirtualThreads flag on SimpleAsyncTaskExecutor.
Includes additional default methods on AsyncTaskExecutor.

Closes gh-30241

build.gradle

@@ -10,6 +10,7 @@ plugins {
 	id 'com.github.johnrengelman.shadow' version '8.1.1' apply false
 	id 'de.undercouch.download' version '5.4.0'
 	id 'me.champeau.jmh' version '0.7.0' apply false
+	id 'me.champeau.mrjar' version '0.1.1'
 }
 
 ext {

ci/images/get-jdk-url.sh

@@ -9,7 +9,7 @@ case "$1" in
 		echo "https://github.com/bell-sw/Liberica/releases/download/20.0.1+10/bellsoft-jdk20.0.1+10-linux-amd64.tar.gz"
 	;;
   java21)
-    echo "https://download.java.net/java/early_access/jdk21/18/GPL/openjdk-21-ea+18_linux-x64_bin.tar.gz"
+    echo "https://download.java.net/java/early_access/jdk21/20/GPL/openjdk-21-ea+20_linux-x64_bin.tar.gz"
   ;;
 	*)
 		echo $"Unknown java version"

spring-context-support/src/main/java/org/springframework/scheduling/quartz/SimpleThreadPoolTaskExecutor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -77,12 +77,6 @@ public class SimpleThreadPoolTaskExecutor extends SimpleThreadPool
 		}
 	}
 
-	@Deprecated
-	@Override
-	public void execute(Runnable task, long startTimeout) {
-		execute(task);
-	}
-
 	@Override
 	public Future<?> submit(Runnable task) {
 		FutureTask<Object> future = new FutureTask<>(task, null);

spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskExecutor.java

@@ -364,12 +364,6 @@ public class ThreadPoolTaskExecutor extends ExecutorConfigurationSupport
 		}
 	}
 
-	@Deprecated
-	@Override
-	public void execute(Runnable task, long startTimeout) {
-		execute(task);
-	}
-
 	@Override
 	public Future<?> submit(Runnable task) {
 		ExecutorService executor = getThreadPoolExecutor();

spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskScheduler.java

@@ -282,12 +282,6 @@ public class ThreadPoolTaskScheduler extends ExecutorConfigurationSupport
 		}
 	}
 
-	@Deprecated
-	@Override
-	public void execute(Runnable task, long startTimeout) {
-		execute(task);
-	}
-
 	@Override
 	public Future<?> submit(Runnable task) {
 		ExecutorService executor = getScheduledExecutor();

spring-core/spring-core.gradle

@@ -1,15 +1,25 @@
 import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
 import org.springframework.build.shadow.ShadowSource
 
+plugins {
+	id 'me.champeau.mrjar'
+}
+
 description = "Spring Core"
 
 apply plugin: "kotlin"
 apply plugin: "kotlinx-serialization"
 
+multiRelease {
+	targetVersions 17, 21
+}
+
 def javapoetVersion = "1.13.0"
 def objenesisVersion = "3.3"
 
 configurations {
+	java21Api.extendsFrom(api)
+	java21Implementation.extendsFrom(implementation)
 	javapoet
 	objenesis
 	graalvm

spring-core/src/main/java/org/springframework/core/task/AsyncTaskExecutor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ package org.springframework.core.task;
 import java.util.concurrent.Callable;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Future;
+import java.util.concurrent.FutureTask;
 
 import org.springframework.util.concurrent.FutureUtils;
 
@@ -60,6 +61,8 @@ public interface AsyncTaskExecutor extends TaskExecutor {
 
 	/**
 	 * Execute the given {@code task}.
+	 * <p>As of 6.1, this method comes with a default implementation that simply
+	 * delegates to {@link #execute(Runnable)}, ignoring the timeout completely.
 	 * @param task the {@code Runnable} to execute (never {@code null})
 	 * @param startTimeout the time duration (milliseconds) within which the task is
 	 * supposed to start. This is intended as a hint to the executor, allowing for
@@ -72,27 +75,41 @@ public interface AsyncTaskExecutor extends TaskExecutor {
 	 * @deprecated as of 5.3.16 since the common executors do not support start timeouts
 	 */
 	@Deprecated
-	void execute(Runnable task, long startTimeout);
+	default void execute(Runnable task, long startTimeout) {
+		execute(task);
+	}
 
 	/**
 	 * Submit a Runnable task for execution, receiving a Future representing that task.
 	 * The Future will return a {@code null} result upon completion.
+	 * <p>As of 6.1, this method comes with a default implementation that delegates
+	 * to {@link #execute(Runnable)}.
 	 * @param task the {@code Runnable} to execute (never {@code null})
 	 * @return a Future representing pending completion of the task
 	 * @throws TaskRejectedException if the given task was not accepted
 	 * @since 3.0
 	 */
-	Future<?> submit(Runnable task);
+	default Future<?> submit(Runnable task) {
+		FutureTask<Object> future = new FutureTask<>(task, null);
+		execute(future);
+		return future;
+	}
 
 	/**
 	 * Submit a Callable task for execution, receiving a Future representing that task.
 	 * The Future will return the Callable's result upon completion.
+	 * <p>As of 6.1, this method comes with a default implementation that delegates
+	 * to {@link #execute(Runnable)}.
 	 * @param task the {@code Callable} to execute (never {@code null})
 	 * @return a Future representing pending completion of the task
 	 * @throws TaskRejectedException if the given task was not accepted
 	 * @since 3.0
 	 */
-	<T> Future<T> submit(Callable<T> task);
+	default <T> Future<T> submit(Callable<T> task) {
+		FutureTask<T> future = new FutureTask<>(task);
+		execute(future, TIMEOUT_INDEFINITE);
+		return future;
+	}
 
 	/**
 	 * Submit a {@code Runnable} task for execution, receiving a {@code CompletableFuture}

spring-core/src/main/java/org/springframework/core/task/SimpleAsyncTaskExecutor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -66,6 +66,9 @@ public class SimpleAsyncTaskExecutor extends CustomizableThreadCreator
 	/** Internal concurrency throttle used by this executor. */
 	private final ConcurrencyThrottleAdapter concurrencyThrottle = new ConcurrencyThrottleAdapter();
 
+	@Nullable
+	private VirtualThreadDelegate virtualThreadDelegate;
+
 	@Nullable
 	private ThreadFactory threadFactory;
 
@@ -97,6 +100,16 @@ public class SimpleAsyncTaskExecutor extends CustomizableThreadCreator
 	}
 
 
+	/**
+	 * Switch this executor to virtual threads. Requires Java 21 or higher.
+	 * <p>The default is {@code false}, indicating platform threads.
+	 * Set this flag to {@code true} in order to create virtual threads instead.
+	 * @since 6.1
+	 */
+	public void setVirtualThreads(boolean virtual) {
+		this.virtualThreadDelegate = (virtual ? new VirtualThreadDelegate() : null);
+	}
+
 	/**
 	 * Specify an external factory to use for creating new Threads,
 	 * instead of relying on the local properties of this executor.
@@ -238,11 +251,16 @@ public class SimpleAsyncTaskExecutor extends CustomizableThreadCreator
 	 * Template method for the actual execution of a task.
 	 * <p>The default implementation creates a new Thread and starts it.
 	 * @param task the Runnable to execute
+	 * @see #setVirtualThreads
 	 * @see #setThreadFactory
 	 * @see #createThread
 	 * @see java.lang.Thread#start()
 	 */
 	protected void doExecute(Runnable task) {
+		if (this.virtualThreadDelegate != null) {
+			this.virtualThreadDelegate.startVirtualThread(nextThreadName(), task);
+		}
+
 		Thread thread = (this.threadFactory != null ? this.threadFactory.newThread(task) : createThread(task));
 		thread.start();
 	}

spring-core/src/main/java/org/springframework/core/task/VirtualThreadDelegate.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2002-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.task;
+
+import java.util.concurrent.ThreadFactory;
+
+/**
+ * Internal delegate for virtual thread handling on JDK 21.
+ * This is a dummy version for reachability on JDK <21.
+ *
+ * @author Juergen Hoeller
+ * @since 6.1
+ * @see VirtualThreadTaskExecutor
+ */
+class VirtualThreadDelegate {
+
+	public VirtualThreadDelegate() {
+		throw new UnsupportedOperationException("Virtual threads not supported on JDK <21");
+	}
+
+	public ThreadFactory virtualThreadFactory() {
+		throw new UnsupportedOperationException();
+	}
+
+	public ThreadFactory virtualThreadFactory(String threadNamePrefix) {
+		throw new UnsupportedOperationException();
+	}
+
+	public Thread startVirtualThread(String name, Runnable task) {
+		throw new UnsupportedOperationException();
+	}
+
+}

spring-core/src/main/java/org/springframework/core/task/VirtualThreadTaskExecutor.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2002-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.task;
+
+import java.util.concurrent.ThreadFactory;
+
+/**
+ * A {@link TaskExecutor} implementation based on virtual threads in JDK 21+.
+ * The only configuration option is a thread name prefix.
+ *
+ * <p>For additional features such as concurrency limiting or task decoration,
+ * consider using {@link SimpleAsyncTaskExecutor#setVirtualThreads} instead.
+ *
+ * @author Juergen Hoeller
+ * @since 6.1
+ * @see SimpleAsyncTaskExecutor
+ */
+public class VirtualThreadTaskExecutor implements AsyncTaskExecutor {
+
+	private final ThreadFactory virtualThreadFactory;
+
+
+	/**
+	 * Create a new {@code VirtualThreadTaskExecutor} without thread naming.
+	 */
+	public VirtualThreadTaskExecutor() {
+		this.virtualThreadFactory = new VirtualThreadDelegate().virtualThreadFactory();
+	}
+
+	/**
+	 * Create a new {@code VirtualThreadTaskExecutor} with thread names based
+	 * on the given thread name prefix followed by a counter (e.g. "test-0").
+	 * @param threadNamePrefix the prefix for thread names (e.g. "test-")
+	 */
+	public VirtualThreadTaskExecutor(String threadNamePrefix) {
+		this.virtualThreadFactory = new VirtualThreadDelegate().virtualThreadFactory(threadNamePrefix);
+	}
+
+
+	/**
+	 * Return the underlying virtual {@link ThreadFactory}.
+	 * Can also be used for custom thread creation elsewhere.
+	 */
+	public final ThreadFactory getVirtualThreadFactory() {
+		return this.virtualThreadFactory;
+	}
+
+	@Override
+	public void execute(Runnable task) {
+		this.virtualThreadFactory.newThread(task).start();
+	}
+
+}

spring-core/src/main/java/org/springframework/core/task/support/TaskExecutorAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -98,12 +98,6 @@ public class TaskExecutorAdapter implements AsyncListenableTaskExecutor {
 		}
 	}
 
-	@Deprecated
-	@Override
-	public void execute(Runnable task, long startTimeout) {
-		execute(task);
-	}
-
 	@Override
 	public Future<?> submit(Runnable task) {
 		try {

spring-core/src/main/java21/org/springframework/core/task/VirtualThreadDelegate.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2002-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.task;
+
+import java.util.concurrent.ThreadFactory;
+
+/**
+ * Internal delegate for virtual thread handling on JDK 21.
+ * This is the actual version compiled against JDK 21.
+ *
+ * @author Juergen Hoeller
+ * @since 6.1
+ * @see VirtualThreadTaskExecutor
+ */
+class VirtualThreadDelegate {
+
+	private final Thread.Builder threadBuilder = Thread.ofVirtual();
+
+	public ThreadFactory virtualThreadFactory() {
+		return this.threadBuilder.factory();
+	}
+
+	public ThreadFactory virtualThreadFactory(String threadNamePrefix) {
+		return this.threadBuilder.name(threadNamePrefix, 0).factory();
+	}
+
+	public Thread startVirtualThread(String name, Runnable task) {
+		return this.threadBuilder.name(name).start(task);
+	}
+
+}

spring-core/src/test/java/org/springframework/core/io/ClassPathResourceTests.java

@@ -214,7 +214,7 @@ class ClassPathResourceTests {
 
 	@Test
 	void directoryNotReadable() throws Exception {
-		Resource fileDir = new ClassPathResource("org/springframework/core");
+		Resource fileDir = new ClassPathResource("example/type");
 		assertThat(fileDir.getURL()).asString().startsWith("file:");
 		assertThat(fileDir.exists()).isTrue();
 		assertThat(fileDir.isReadable()).isFalse();

spring-core/src/test/java/org/springframework/core/io/ResourceTests.java

@@ -68,8 +68,8 @@ class ResourceTests {
 	@ParameterizedTest(name = "{index}: {0}")
 	@MethodSource("resource")
 	void resourceIsValid(Resource resource) throws Exception {
-		assertThat(resource.getFilename()).isEqualTo("Resource.class");
+		assertThat(resource.getFilename()).isEqualTo("ResourceTests.class");
-		assertThat(resource.getURL().getFile()).endsWith("Resource.class");
+		assertThat(resource.getURL().getFile()).endsWith("ResourceTests.class");
 		assertThat(resource.exists()).isTrue();
 		assertThat(resource.isReadable()).isTrue();
 		assertThat(resource.contentLength()).isGreaterThan(0);
@@ -80,9 +80,9 @@ class ResourceTests {
 	@ParameterizedTest(name = "{index}: {0}")
 	@MethodSource("resource")
 	void resourceCreateRelative(Resource resource) throws Exception {
-		Resource relative1 = resource.createRelative("ClassPathResource.class");
+		Resource relative1 = resource.createRelative("ClassPathResourceTests.class");
-		assertThat(relative1.getFilename()).isEqualTo("ClassPathResource.class");
+		assertThat(relative1.getFilename()).isEqualTo("ClassPathResourceTests.class");
-		assertThat(relative1.getURL().getFile().endsWith("ClassPathResource.class")).isTrue();
+		assertThat(relative1.getURL().getFile().endsWith("ClassPathResourceTests.class")).isTrue();
 		assertThat(relative1.exists()).isTrue();
 		assertThat(relative1.isReadable()).isTrue();
 		assertThat(relative1.contentLength()).isGreaterThan(0);
@@ -92,9 +92,9 @@ class ResourceTests {
 	@ParameterizedTest(name = "{index}: {0}")
 	@MethodSource("resource")
 	void resourceCreateRelativeWithFolder(Resource resource) throws Exception {
-		Resource relative2 = resource.createRelative("support/ResourcePatternResolver.class");
+		Resource relative2 = resource.createRelative("support/PathMatchingResourcePatternResolverTests.class");
-		assertThat(relative2.getFilename()).isEqualTo("ResourcePatternResolver.class");
+		assertThat(relative2.getFilename()).isEqualTo("PathMatchingResourcePatternResolverTests.class");
-		assertThat(relative2.getURL().getFile()).endsWith("ResourcePatternResolver.class");
+		assertThat(relative2.getURL().getFile()).endsWith("PathMatchingResourcePatternResolverTests.class");
 		assertThat(relative2.exists()).isTrue();
 		assertThat(relative2.isReadable()).isTrue();
 		assertThat(relative2.contentLength()).isGreaterThan(0);
@@ -104,9 +104,9 @@ class ResourceTests {
 	@ParameterizedTest(name = "{index}: {0}")
 	@MethodSource("resource")
 	void resourceCreateRelativeWithDotPath(Resource resource) throws Exception {
-		Resource relative3 = resource.createRelative("../SpringVersion.class");
+		Resource relative3 = resource.createRelative("../CollectionFactoryTests.class");
-		assertThat(relative3.getFilename()).isEqualTo("SpringVersion.class");
+		assertThat(relative3.getFilename()).isEqualTo("CollectionFactoryTests.class");
-		assertThat(relative3.getURL().getFile()).endsWith("SpringVersion.class");
+		assertThat(relative3.getURL().getFile()).endsWith("CollectionFactoryTests.class");
 		assertThat(relative3.exists()).isTrue();
 		assertThat(relative3.isReadable()).isTrue();
 		assertThat(relative3.contentLength()).isGreaterThan(0);
@@ -128,12 +128,12 @@ class ResourceTests {
 	}
 
 	private static Stream<Arguments> resource() throws URISyntaxException {
-		URL resourceClass = ResourceTests.class.getResource("Resource.class");
+		URL resourceClass = ResourceTests.class.getResource("ResourceTests.class");
 		Path resourceClassFilePath = Paths.get(resourceClass.toURI());
 		return Stream.of(
-				arguments(named("ClassPathResource", new ClassPathResource("org/springframework/core/io/Resource.class"))),
+				arguments(named("ClassPathResource", new ClassPathResource("org/springframework/core/io/ResourceTests.class"))),
-				arguments(named("ClassPathResource with ClassLoader", new ClassPathResource("org/springframework/core/io/Resource.class", ResourceTests.class.getClassLoader()))),
+				arguments(named("ClassPathResource with ClassLoader", new ClassPathResource("org/springframework/core/io/ResourceTests.class", ResourceTests.class.getClassLoader()))),
-				arguments(named("ClassPathResource with Class", new ClassPathResource("Resource.class", ResourceTests.class))),
+				arguments(named("ClassPathResource with Class", new ClassPathResource("ResourceTests.class", ResourceTests.class))),
 				arguments(named("FileSystemResource", new FileSystemResource(resourceClass.getFile()))),
 				arguments(named("FileSystemResource with File", new FileSystemResource(new File(resourceClass.getFile())))),
 				arguments(named("FileSystemResource with File path", new FileSystemResource(resourceClassFilePath))),
@@ -220,29 +220,29 @@ class ResourceTests {
 
 		@Test
 		void sameResourceIsEqual() {
-			String file = getClass().getResource("Resource.class").getFile();
+			String file = getClass().getResource("ResourceTests.class").getFile();
 			Resource resource = new FileSystemResource(file);
 			assertThat(resource).isEqualTo(new FileSystemResource(file));
 		}
 
 		@Test
 		void sameResourceFromFileIsEqual() {
-			File file = new File(getClass().getResource("Resource.class").getFile());
+			File file = new File(getClass().getResource("ResourceTests.class").getFile());
 			Resource resource = new FileSystemResource(file);
 			assertThat(resource).isEqualTo(new FileSystemResource(file));
 		}
 
 		@Test
 		void sameResourceFromFilePathIsEqual() throws Exception {
-			Path filePath = Paths.get(getClass().getResource("Resource.class").toURI());
+			Path filePath = Paths.get(getClass().getResource("ResourceTests.class").toURI());
 			Resource resource = new FileSystemResource(filePath);
 			assertThat(resource).isEqualTo(new FileSystemResource(filePath));
 		}
 
 		@Test
 		void sameResourceFromDotPathIsEqual() {
-			Resource resource = new FileSystemResource("core/io/Resource.class");
+			Resource resource = new FileSystemResource("core/io/ResourceTests.class");
-			assertThat(new FileSystemResource("core/../core/io/./Resource.class")).isEqualTo(resource);
+			assertThat(new FileSystemResource("core/../core/io/./ResourceTests.class")).isEqualTo(resource);
 		}
 
 		@Test
@@ -254,7 +254,7 @@ class ResourceTests {
 
 		@Test
 		void readableChannelProvidesContent() throws Exception {
-			Resource resource = new FileSystemResource(getClass().getResource("Resource.class").getFile());
+			Resource resource = new FileSystemResource(getClass().getResource("ResourceTests.class").getFile());
 			try (ReadableByteChannel channel = resource.readableChannel()) {
 				ByteBuffer buffer = ByteBuffer.allocate((int) resource.contentLength());
 				channel.read(buffer);
@@ -293,8 +293,8 @@ class ResourceTests {
 
 		@Test
 		void sameResourceWithRelativePathIsEqual() throws Exception {
-			Resource resource = new UrlResource("file:core/io/Resource.class");
+			Resource resource = new UrlResource("file:core/io/ResourceTests.class");
-			assertThat(new UrlResource("file:core/../core/io/./Resource.class")).isEqualTo(resource);
+			assertThat(new UrlResource("file:core/../core/io/./ResourceTests.class")).isEqualTo(resource);
 		}
 
 		@Test
@@ -322,14 +322,14 @@ class ResourceTests {
 
 		@Test
 		void factoryMethodsProduceEqualResources() throws Exception {
-			Resource resource1 = new UrlResource("file:core/io/Resource.class");
+			Resource resource1 = new UrlResource("file:core/io/ResourceTests.class");
-			Resource resource2 = UrlResource.from("file:core/io/Resource.class");
+			Resource resource2 = UrlResource.from("file:core/io/ResourceTests.class");
 			Resource resource3 = UrlResource.from(resource1.getURI());
 
 			assertThat(resource2.getURL()).isEqualTo(resource1.getURL());
 			assertThat(resource3.getURL()).isEqualTo(resource1.getURL());
 
-			assertThat(UrlResource.from("file:core/../core/io/./Resource.class")).isEqualTo(resource1);
+			assertThat(UrlResource.from("file:core/../core/io/./ResourceTests.class")).isEqualTo(resource1);
 			assertThat(UrlResource.from("file:/dir/test.txt?argh").getFilename()).isEqualTo("test.txt");
 			assertThat(UrlResource.from("file:\\dir\\test.txt?argh").getFilename()).isEqualTo("test.txt");
 			assertThat(UrlResource.from("file:\\dir/test.txt?argh").getFilename()).isEqualTo("test.txt");
@@ -433,7 +433,6 @@ class ResourceTests {
 				public String getDescription() {
 					return name;
 				}
-
 				@Override
 				public InputStream getInputStream() throws IOException {
 					throw new FileNotFoundException();
@@ -459,7 +458,6 @@ class ResourceTests {
 				public InputStream getInputStream() {
 					return new ByteArrayInputStream(new byte[] {'a', 'b', 'c'});
 				}
-
 				@Override
 				public String getDescription() {
 					return "";

spring-core/src/test/java21/org/springframework/core/task/VirtualThreadTaskExecutorTests.java

@@ -0,0 +1,142 @@
+/*
+ * Copyright 2002-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.task;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Juergen Hoeller
+ * @since 6.1
+ */
+class VirtualThreadTaskExecutorTests {
+
+	@Test
+	void virtualThreadsWithoutName() {
+		final Object monitor = new Object();
+		VirtualThreadTaskExecutor executor = new VirtualThreadTaskExecutor();
+		ThreadNameHarvester task = new ThreadNameHarvester(monitor);
+		executeAndWait(executor, task, monitor);
+		assertThat(task.getThreadName()).isEmpty();
+		assertThat(task.isVirtual()).isTrue();
+	}
+
+	@Test
+	void virtualThreadsWithNamePrefix() {
+		final Object monitor = new Object();
+		VirtualThreadTaskExecutor executor = new VirtualThreadTaskExecutor("test-");
+		ThreadNameHarvester task = new ThreadNameHarvester(monitor);
+		executeAndWait(executor, task, monitor);
+		assertThat(task.getThreadName()).isEqualTo("test-0");
+		assertThat(task.isVirtual()).isTrue();
+	}
+
+	@Test
+	void simpleWithVirtualThreadFactory() {
+		final Object monitor = new Object();
+		SimpleAsyncTaskExecutor executor = new SimpleAsyncTaskExecutor(Thread.ofVirtual().name("test").factory());
+		ThreadNameHarvester task = new ThreadNameHarvester(monitor);
+		executeAndWait(executor, task, monitor);
+		assertThat(task.getThreadName()).isEqualTo("test");
+		assertThat(task.isVirtual()).isTrue();
+	}
+
+	@Test
+	void simpleWithVirtualThreadFlag() {
+		final String customPrefix = "chankPop#";
+		final Object monitor = new Object();
+		SimpleAsyncTaskExecutor executor = new SimpleAsyncTaskExecutor(customPrefix);
+		executor.setVirtualThreads(true);
+		ThreadNameHarvester task = new ThreadNameHarvester(monitor);
+		executeAndWait(executor, task, monitor);
+		assertThat(task.getThreadName()).startsWith(customPrefix);
+		assertThat(task.isVirtual()).isTrue();
+	}
+
+	private void executeAndWait(TaskExecutor executor, Runnable task, Object monitor) {
+		synchronized (monitor) {
+			executor.execute(task);
+			try {
+				monitor.wait();
+			}
+			catch (InterruptedException ignored) {
+			}
+		}
+	}
+
+
+	private static final class NoOpRunnable implements Runnable {
+
+		@Override
+		public void run() {
+			// no-op
+		}
+	}
+
+
+	private static abstract class AbstractNotifyingRunnable implements Runnable {
+
+		private final Object monitor;
+
+		protected AbstractNotifyingRunnable(Object monitor) {
+			this.monitor = monitor;
+		}
+
+		@Override
+		public final void run() {
+			synchronized (this.monitor) {
+				try {
+					doRun();
+				}
+				finally {
+					this.monitor.notifyAll();
+				}
+			}
+		}
+
+		protected abstract void doRun();
+	}
+
+
+	private static final class ThreadNameHarvester extends AbstractNotifyingRunnable {
+
+		private String threadName;
+
+		private boolean virtual;
+
+		protected ThreadNameHarvester(Object monitor) {
+			super(monitor);
+		}
+
+		public String getThreadName() {
+			return this.threadName;
+		}
+
+		public boolean isVirtual() {
+			return this.virtual;
+		}
+
+		@Override
+		protected void doRun() {
+			Thread thread = Thread.currentThread();
+			this.threadName = thread.getName();
+			this.virtual = thread.isVirtual();
+		}
+	}
+
+}

src/checkstyle/checkstyle-suppressions.xml

@@ -11,9 +11,9 @@
 	<suppress files="(^(?!.+[\\/]src[\\/]main[\\/]java[\\/].*package-info\.java))|(.*framework-docs.*)|(.*spring-(context-indexer|instrument|jcl).*)" checks="RegexpSinglelineJava" id="packageLevelNonNullFieldsAnnotation" />
 
 	<!-- Global: tests and test fixtures -->
-	<suppress files="[\\/]src[\\/](test|testFixtures)[\\/]java[\\/]" checks="AnnotationLocation|AnnotationUseStyle|AtclauseOrder|AvoidNestedBlocks|FinalClass|HideUtilityClassConstructor|InnerTypeLast|JavadocStyle|JavadocType|JavadocVariable|LeftCurly|MultipleVariableDeclarations|NeedBraces|OneTopLevelClass|OuterTypeFilename|RequireThis|SpringCatch|SpringJavadoc|SpringNoThis"/>
+	<suppress files="[\\/]src[\\/](test|testFixtures)[\\/](java|java21)[\\/]" checks="AnnotationLocation|AnnotationUseStyle|AtclauseOrder|AvoidNestedBlocks|FinalClass|HideUtilityClassConstructor|InnerTypeLast|JavadocStyle|JavadocType|JavadocVariable|LeftCurly|MultipleVariableDeclarations|NeedBraces|OneTopLevelClass|OuterTypeFilename|RequireThis|SpringCatch|SpringJavadoc|SpringNoThis"/>
-	<suppress files="[\\/]src[\\/](test|testFixtures)[\\/]java[\\/]org[\\/]springframework[\\/].+(Tests|Suite)" checks="IllegalImport" id="bannedJUnitJupiterImports"/>
+	<suppress files="[\\/]src[\\/](test|testFixtures)[\\/]java[\\/]org[\\/]springframework[\\/].+(Tests|Suite)" checks="IllegalImport" id="bannedJUnitJupiterImports"/>		<suppress files="[\\/]src[\\/](test|testFixtures)[\\/](java|java21)[\\/]org[\\/]springframework[\\/].+(Tests|Suite)" checks="IllegalImport" id="bannedJUnitJupiterImports"/>
-	<suppress files="[\\/]src[\\/](test|testFixtures)[\\/]java[\\/]" checks="SpringJUnit5" message="should not be public"/>
+	<suppress files="[\\/]src[\\/](test|testFixtures)[\\/]java[\\/]" checks="SpringJUnit5" message="should not be public"/>		<suppress files="[\\/]src[\\/](test|testFixtures)[\\/](java|java21)[\\/]" checks="SpringJUnit5" message="should not be public"/>
 
 	<!-- JMH benchmarks -->
 	<suppress files="[\\/]src[\\/]jmh[\\/]java[\\/]org[\\/]springframework[\\/]" checks="JavadocVariable|JavadocStyle|InnerTypeLast"/>