Add info contributor support for JDK 24's VirtualThreadSchedulerMXBean

See gh-43594

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/info/ProcessInfo.java

@@ -24,6 +24,7 @@ import java.lang.management.MemoryUsage;
  * Information about the process of the application.
  *
  * @author Jonatan Ivanov
+ * @author Andrey Litvitski
  * @since 3.3.0
  */
 public class ProcessInfo {
@@ -72,6 +73,29 @@ public class ProcessInfo {
 		return new MemoryInfo();
 	}
 
+	/**
+	 * Virtual threads information for the process. These values provide details about the
+	 * current state of virtual threads, including the number of mounted threads, queued threads,
+	 * the parallelism level, and the thread pool size.
+	 * @return an instance of {@link VirtualThreadsInfo} containing information about virtual threads,
+	 * or {@code null} if the VirtualThreadSchedulerMXBean is not available.
+	 * @since 3.5.0
+	 */
+	public VirtualThreadsInfo getVirtualThreads() {
+		try {
+			Class mxBeanClass = Class.forName("jdk.management.VirtualThreadSchedulerMXBean");
+			Object bean = ManagementFactory.getPlatformMXBean(mxBeanClass);
+			return new VirtualThreadsInfo(
+					(Integer) mxBeanClass.getMethod("getMountedVirtualThreadCount").invoke(bean),
+					(Long) mxBeanClass.getMethod("getQueuedVirtualThreadCount").invoke(bean),
+					(Integer) mxBeanClass.getMethod("getParallelism").invoke(bean),
+					(Integer) mxBeanClass.getMethod("getPoolSize").invoke(bean)
+			);
+		} catch (ReflectiveOperationException e) {
+			return null;
+		}
+	}
+
 	public long getPid() {
 		return this.pid;
 	}
@@ -84,6 +108,46 @@ public class ProcessInfo {
 		return this.owner;
 	}
 
+	/**
+	 * Virtual threads information.
+	 *
+	 * @since 3.5.0
+	 */
+	public static class VirtualThreadsInfo {
+
+		private final int mounted;
+
+		private final long queued;
+
+		private final int parallelism;
+
+		private final int poolSize;
+
+		public VirtualThreadsInfo(int mounted, long queued, int parallelism, int poolSize) {
+			this.mounted = mounted;
+			this.queued = queued;
+			this.parallelism = parallelism;
+			this.poolSize = poolSize;
+		}
+
+		public long getMounted() {
+			return this.mounted;
+		}
+
+		public long getQueued() {
+			return this.queued;
+		}
+
+		public int getParallelism() {
+			return this.parallelism;
+		}
+
+		public int getPoolSize() {
+			return this.poolSize;
+		}
+
+	}
+
 	/**
 	 * Memory information.
 	 *

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/info/ProcessInfoTests.java

@@ -19,6 +19,8 @@ package org.springframework.boot.info;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.info.ProcessInfo.MemoryInfo.MemoryUsageInfo;
+import org.springframework.boot.info.ProcessInfo.VirtualThreadsInfo;
+import org.springframework.util.ClassUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -26,6 +28,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * Tests for {@link ProcessInfo}.
  *
  * @author Jonatan Ivanov
+ * @author Andrey Litvitski
  */
 class ProcessInfoTests {
 
@@ -54,4 +57,23 @@ class ProcessInfoTests {
 		assertThat(nonHeapUsageInfo.getMax()).isEqualTo(-1);
 	}
 
+	@Test
+	void virtualThreadsInfoIsNullWhenMXBeanIsNotAccessible() {
+		if (ClassUtils.isPresent("jdk.management.VirtualThreadSchedulerMXBean", null)) {
+			ProcessInfo processInfo = new ProcessInfo();
+
+			VirtualThreadsInfo virtualThreadsInfo = processInfo.getVirtualThreads();
+
+			assertThat(virtualThreadsInfo).isNotNull();
+			assertThat(virtualThreadsInfo.getMounted()).isGreaterThanOrEqualTo(0);
+			assertThat(virtualThreadsInfo.getQueued()).isGreaterThanOrEqualTo(0);
+			assertThat(virtualThreadsInfo.getParallelism()).isGreaterThan(0);
+			assertThat(virtualThreadsInfo.getPoolSize()).isGreaterThan(0);
+		} else {
+			ProcessInfo processInfo = new ProcessInfo();
+
+			assertThat(processInfo.getVirtualThreads()).isNull();
+		}
+	}
+
 }