Fixes #851 - MBeanContainer no longer unregisters MBeans when "stopped".

MBeanContainer now implements Destroyable, so calling Server.destroy()
unregisters the MBeans.

jetty-jmx/src/main/java/org/eclipse/jetty/jmx/MBeanContainer.java

@@ -32,6 +32,7 @@ import javax.management.ObjectName;
 
 import org.eclipse.jetty.util.component.Container;
 import org.eclipse.jetty.util.component.ContainerLifeCycle;
+import org.eclipse.jetty.util.component.Destroyable;
 import org.eclipse.jetty.util.component.Dumpable;
 import org.eclipse.jetty.util.log.Log;
 import org.eclipse.jetty.util.log.Logger;
@@ -39,7 +40,7 @@ import org.eclipse.jetty.util.log.Logger;
 /**
  * Container class for the MBean instances
  */
-public class MBeanContainer implements Container.InheritedListener, Dumpable
+public class MBeanContainer implements Container.InheritedListener, Dumpable, Destroyable
 {
     private final static Logger LOG = Log.getLogger(MBeanContainer.class.getName());
     private final static ConcurrentMap<String, AtomicInteger> __unique = new ConcurrentHashMap<>();
@@ -254,6 +255,7 @@ public class MBeanContainer implements Container.InheritedListener, Dumpable
         return ContainerLifeCycle.dump(this);
     }
 
+    @Override
     public void destroy()
     {
         _beans.values().stream()

jetty-jmx/src/test/java/org/eclipse/jetty/jmx/MBeanContainerLifeCycleTest.java

@@ -0,0 +1,116 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.jmx;
+
+import java.lang.management.ManagementFactory;
+import java.util.Set;
+
+import javax.management.MBeanServer;
+import javax.management.ObjectName;
+
+import org.eclipse.jetty.util.component.ContainerLifeCycle;
+import org.eclipse.jetty.util.thread.QueuedThreadPool;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+public class MBeanContainerLifeCycleTest
+{
+    private ContainerLifeCycle container;
+    private MBeanServer mbeanServer;
+
+    @Before
+    public void prepare() throws Exception
+    {
+        container = new ContainerLifeCycle();
+        mbeanServer = ManagementFactory.getPlatformMBeanServer();
+        MBeanContainer mbeanContainer = new MBeanContainer(mbeanServer);
+        container.addBean(mbeanContainer);
+        container.start();
+    }
+
+    @After
+    public void dispose() throws Exception
+    {
+        container.stop();
+    }
+
+    @Test
+    public void testAddBeanRegistersMBeanRemoveBeanUnregistersMBean() throws Exception
+    {
+        // Adding a bean to the container should register the MBean.
+        QueuedThreadPool bean = new QueuedThreadPool();
+        container.addBean(bean);
+
+        String pkg = bean.getClass().getPackage().getName();
+        Set<ObjectName> objectNames = mbeanServer.queryNames(ObjectName.getInstance(pkg + ":*"), null);
+        Assert.assertEquals(1, objectNames.size());
+
+        // Removing the bean should unregister the MBean.
+        container.removeBean(bean);
+        objectNames = mbeanServer.queryNames(ObjectName.getInstance(pkg + ":*"), null);
+        Assert.assertEquals(0, objectNames.size());
+    }
+
+    @Test
+    public void testStoppingContainerDoesNotUnregistersMBeans() throws Exception
+    {
+        QueuedThreadPool bean = new QueuedThreadPool();
+        container.addBean(bean, true);
+
+        String pkg = bean.getClass().getPackage().getName();
+        Set<ObjectName> objectNames = mbeanServer.queryNames(ObjectName.getInstance(pkg + ":*"), null);
+        Assert.assertEquals(1, objectNames.size());
+
+        container.stop();
+
+        objectNames = mbeanServer.queryNames(ObjectName.getInstance(pkg + ":*"), null);
+        Assert.assertEquals(1, objectNames.size());
+
+        // Remove the MBeans to start clean on the next test.
+        objectNames.forEach(objectName ->
+        {
+            try
+            {
+                mbeanServer.unregisterMBean(objectName);
+            }
+            catch (Throwable ignored)
+            {
+            }
+        });
+    }
+
+    @Test
+    public void testDestroyingContainerUnregistersMBeans() throws Exception
+    {
+        QueuedThreadPool bean = new QueuedThreadPool();
+        container.addBean(bean, true);
+
+        String pkg = bean.getClass().getPackage().getName();
+        Set<ObjectName> objectNames = mbeanServer.queryNames(ObjectName.getInstance(pkg + ":*"), null);
+        Assert.assertEquals(1, objectNames.size());
+
+        container.stop();
+        container.destroy();
+
+        objectNames = mbeanServer.queryNames(ObjectName.getInstance(pkg + ":*"), null);
+        Assert.assertEquals(0, objectNames.size());
+    }
+}