Polish "Add support for virtual threads in OtlpMetricRegistry configuration"

See gh-42407

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/otlp/OtlpMetricsExportAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -76,7 +76,7 @@ public class OtlpMetricsExportAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	@ConditionalOnThreading(Threading.PLATFORM)
-	public OtlpMeterRegistry otlpMeterRegistryPlatformThreads(OtlpConfig otlpConfig, Clock clock) {
+	public OtlpMeterRegistry otlpMeterRegistry(OtlpConfig otlpConfig, Clock clock) {
 		return new OtlpMeterRegistry(otlpConfig, clock);
 	}
 
@@ -84,7 +84,7 @@ public class OtlpMetricsExportAutoConfiguration {
 	@ConditionalOnMissingBean
 	@ConditionalOnThreading(Threading.VIRTUAL)
 	public OtlpMeterRegistry otlpMeterRegistryVirtualThreads(OtlpConfig otlpConfig, Clock clock) {
-		VirtualThreadTaskExecutor taskExecutor = new VirtualThreadTaskExecutor("otlp-meter-registry");
+		VirtualThreadTaskExecutor taskExecutor = new VirtualThreadTaskExecutor("otlp-meter-registry-");
 		return new OtlpMeterRegistry(otlpConfig, clock, taskExecutor.getVirtualThreadFactory());
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/assertj/ScheduledExecutorServiceAssert.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.testsupport.assertj;
 
+import java.lang.reflect.Method;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
@@ -24,6 +25,8 @@ import java.util.concurrent.TimeUnit;
 import org.assertj.core.api.AbstractAssert;
 import org.assertj.core.api.Assert;
 
+import org.springframework.util.ReflectionUtils;
+
 /**
  * AssertJ {@link Assert} for {@link ScheduledThreadPoolExecutor}.
  *
@@ -66,12 +69,11 @@ public final class ScheduledExecutorServiceAssert
 	private boolean producesVirtualThreads() {
 		try {
 			return this.actual.schedule(() -> {
-				// https://openjdk.org/jeps/444
-				// jep 444 specifies that virtual threads will belong to
-				// a special thread group given the name "VirtualThreads"
-				ThreadGroup threadGroup = Thread.currentThread().getThreadGroup();
-				String threadGroupName = (threadGroup != null) ? threadGroup.getName() : "";
-				return threadGroupName.equalsIgnoreCase("VirtualThreads");
+				Method isVirtual = ReflectionUtils.findMethod(Thread.class, "isVirtual");
+				if (isVirtual == null) {
+					return false;
+				}
+				return (boolean) ReflectionUtils.invokeMethod(isVirtual, Thread.currentThread());
 			}, 0, TimeUnit.SECONDS).get();
 		}
 		catch (InterruptedException | ExecutionException ex) {