--- /dev/null	2018-06-17 23:18:20.806999507 +0800
+++ new/test/jdk/jfr/api/metadata/eventtype/TestUnloadingEventClass.java	2019-01-29 11:01:28.783373469 +0800
@@ -0,0 +1,178 @@
+/*
+ * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.api.metadata.eventtype;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import jdk.jfr.Event;
+import jdk.jfr.EventType;
+import jdk.jfr.FlightRecorder;
+import jdk.jfr.Recording;
+import jdk.jfr.consumer.RecordingFile;
+import jdk.jfr.internal.JVM;
+
+/*
+ * @test
+ * @key jfr
+ * @summary Test that verifies event metadata is removed when an event class is unloaded.
+ *
+ * @library /lib/testlibrary
+ * @modules jdk.jfr/jdk.jfr.internal
+ *          java.base/jdk.internal.misc
+ *
+ * @run main/othervm jdk.jfr.api.metadata.eventtype.TestUnloadingEventClass
+ */
+public class TestUnloadingEventClass {
+
+    private static final String EVENT_NAME = "jdk.jfr.api.metadata.eventtype.TestUnloadingEventClass$ToBeUnloaded";
+
+    public static class ToBeUnloaded extends Event {
+    }
+
+    static public class MyClassLoader extends ClassLoader {
+        public MyClassLoader() {
+            super( null);
+        }
+
+        public final Class<?> defineClass(String name, byte[] b) {
+            return super.defineClass(name, b, 0, b.length);
+        }
+    }
+
+    private static final JVM jvm = JVM.getJVM();
+    public static ClassLoader myClassLoader;
+
+    public static void main(String[] args) throws Throwable {
+        assertEventTypeNotAvailable();
+        myClassLoader = createClassLoaderWithEventClass();
+
+        try (Recording r0 = new Recording()) {
+            r0.start();
+            r0.stop();
+            if (getEventType(r0, 0, EVENT_NAME) == null) {
+                throw new Exception("Expected event class to have corresponding event type");
+            }
+        }
+
+        try (Recording r1 = new Recording(); Recording r2 = new Recording(); Recording r3 = new Recording()) {
+            r1.start();
+            r2.start();
+            unLoadEventClass();
+            r3.start();
+
+            assertEventTypeNotAvailable();
+            r3.stop();
+            r2.stop();
+            r1.stop();
+
+            if (getEventType(r1, 1, EVENT_NAME) == null) {
+                throw new Exception("Expected event class to have corresponding event type in recording with all chunks");
+            }
+            if (getEventType(r2, 2, EVENT_NAME) == null) {
+                throw new Exception("Expected event class to have corresponding event type in recording where event class was unloaded");
+            }
+            if (getEventType(r3, 3, EVENT_NAME) != null) {
+                throw new Exception("Unexpected metadata found for event class tha has been unloaded.");
+            }
+        }
+    }
+
+    private static MyClassLoader createClassLoaderWithEventClass() throws Exception {
+        String resourceName = EVENT_NAME.replace('.', '/') + ".class";
+        try (InputStream is = TestUnloadingEventClass.class.getClassLoader().getResourceAsStream(resourceName)) {
+            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            byte[] buffer = new byte[4096];
+            int byteValue = 0;
+            while ((byteValue = is.read(buffer, 0, buffer.length)) != -1) {
+                baos.write(buffer, 0, byteValue);
+            }
+            baos.flush();
+            MyClassLoader myClassLoader = new MyClassLoader();
+            Class<?> eventClass = myClassLoader.defineClass(EVENT_NAME, baos.toByteArray());
+            if (eventClass == null) {
+                throw new Exception("Could not define test class");
+            }
+            if (eventClass.getSuperclass() != Event.class) {
+                throw new Exception("Superclass should be jdk.jfr.Event");
+            }
+            if (eventClass.getSuperclass().getClassLoader() != null) {
+                throw new Exception("Class loader of jdk.jfr.Event should be null");
+            }
+            if (eventClass.getClassLoader() != myClassLoader) {
+                throw new Exception("Incorrect class loader for event class");
+            }
+            eventClass.newInstance(); // force <clinit>
+            return myClassLoader;
+        }
+    }
+
+    private static void unLoadEventClass() throws Exception {
+        long firstCount = jvm.getUnloadedEventClassCount();
+        System.out.println("Initial unloaded count: " + firstCount);
+        myClassLoader = null;
+        System.out.println("Cleared reference to MyClassLoader");
+        long newCount = 0;
+        do {
+            System.out.println("GC triggered");
+            System.gc();
+            Thread.sleep(1000);
+            newCount = jvm.getUnloadedEventClassCount();
+            System.out.println("Unloaded count: " + newCount);
+        } while (firstCount + 1 != newCount);
+        System.out.println("Event class unloaded!");
+        System.out.println("Event classes currently on the heap:");
+        for (Class<?> eventClass : JVM.getJVM().getAllEventClasses()) {
+        }
+
+    }
+
+    private static void assertEventTypeNotAvailable() throws Exception {
+        for (EventType type : FlightRecorder.getFlightRecorder().getEventTypes()) {
+            if (type.getName().equals(EVENT_NAME)) {
+                throw new Exception("Event type should not be available");
+            }
+        }
+    }
+
+    private static Object getEventType(Recording r, long id, String eventName) throws IOException {
+        Path p = Files.createTempFile("recording-" + id + "_", ".jfr");
+        r.dump(p);
+        try (RecordingFile rf = new RecordingFile(p)) {
+            for (EventType et : rf.readEventTypes()) {
+                if (et.getName().equals(eventName)) {
+                    return et;
+                }
+            }
+
+        }
+        return null;
+    }
+}
+