Reinstate test for JmxUtils.locateMBeanServer()

spring-context/src/test/java/org/springframework/jmx/support/JmxUtilsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.jmx.support;
 import java.beans.PropertyDescriptor;
 
 import javax.management.DynamicMBean;
+import javax.management.MBeanServer;
 import javax.management.MalformedObjectNameException;
 import javax.management.NotCompliantMBeanException;
 import javax.management.ObjectName;
@@ -30,6 +31,7 @@ import org.springframework.beans.BeanWrapperImpl;
 import org.springframework.jmx.IJmxTestBean;
 import org.springframework.jmx.JmxTestBean;
 import org.springframework.jmx.export.TestDynamicMBean;
+import org.springframework.util.MBeanTestUtils;
 import org.springframework.util.ObjectUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -39,6 +41,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Rob Harrop
  * @author Juergen Hoeller
+ * @author Sam Brannen
  */
 class JmxUtilsTests {
 
@@ -124,6 +127,20 @@ class JmxUtilsTests {
 		assertThat(uniqueName.getKeyProperty(JmxUtils.IDENTITY_OBJECT_NAME_KEY)).as("Identity key is incorrect").isEqualTo(ObjectUtils.getIdentityHexString(managedResource));
 	}
 
+	@Test
+	void locatePlatformMBeanServer() {
+		MBeanServer server = null;
+		try {
+			server = JmxUtils.locateMBeanServer();
+			assertThat(server).isNotNull();
+		}
+		finally {
+			if (server != null) {
+				MBeanTestUtils.releaseMBeanServer(server);
+			}
+		}
+	}
+
 
 	public static class AttributeTestBean {
 

spring-context/src/test/java/org/springframework/util/MBeanTestUtils.java

@@ -23,22 +23,34 @@ import javax.management.MBeanServerFactory;
  * Utilities for MBean tests.
  *
  * @author Phillip Webb
+ * @author Sam Brannen
  */
 public class MBeanTestUtils {
 
 	/**
-	 * Resets {@link MBeanServerFactory} to a known consistent state.
-	 * <p>This involves releasing all currently registered MBeanServers.
+	 * Reset the {@link MBeanServerFactory} to a known consistent state. This involves
+	 * {@linkplain #releaseMBeanServer(MBeanServer) releasing} all currently registered
+	 * MBeanServers.
 	 */
 	public static synchronized void resetMBeanServers() throws Exception {
 		for (MBeanServer server : MBeanServerFactory.findMBeanServer(null)) {
-			try {
-				MBeanServerFactory.releaseMBeanServer(server);
-			}
-			catch (IllegalArgumentException ex) {
-				if (!ex.getMessage().contains("not in list")) {
-					throw ex;
-				}
+			releaseMBeanServer(server);
+		}
+	}
+
+	/**
+	 * Attempt to release the supplied {@link MBeanServer}.
+	 * <p>Ignores any {@link IllegalArgumentException} thrown by
+	 * {@link MBeanServerFactory#releaseMBeanServer(MBeanServer)} whose error
+	 * message contains the text "not in list".
+	 */
+	public static void releaseMBeanServer(MBeanServer server) {
+		try {
+			MBeanServerFactory.releaseMBeanServer(server);
+		}
+		catch (IllegalArgumentException ex) {
+			if (!ex.getMessage().contains("not in list")) {
+				throw ex;
 			}
 		}
 	}