1 /*
   2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.jfr.api.metadata.eventtype;
  27 
  28 import java.io.ByteArrayOutputStream;
  29 import java.io.IOException;
  30 import java.io.InputStream;
  31 import java.nio.file.Path;
  32 
  33 import jdk.jfr.Event;
  34 import jdk.jfr.EventType;
  35 import jdk.jfr.FlightRecorder;
  36 import jdk.jfr.Recording;
  37 import jdk.jfr.consumer.RecordingFile;
  38 import jdk.jfr.internal.JVM;
  39 import jdk.test.lib.Utils;
  40 
  41 /**
  42  * @test
  43  * @key jfr
  44  * @summary Test that verifies event metadata is removed when an event class is unloaded.
  45  * @requires vm.hasJFR
  46  *
  47  * @library /test/lib
  48  * @modules jdk.jfr/jdk.jfr.internal
  49  *          java.base/jdk.internal.misc
  50  *
  51  * @run main/othervm -Xlog:class+unload -Xlog:gc jdk.jfr.api.metadata.eventtype.TestUnloadingEventClass
  52  */
  53 public class TestUnloadingEventClass {
  54 
  55     private static final String EVENT_NAME = "jdk.jfr.api.metadata.eventtype.TestUnloadingEventClass$ToBeUnloaded";
  56 
  57     public static class ToBeUnloaded extends Event {
  58     }
  59 
  60     static public class MyClassLoader extends ClassLoader {
  61         public MyClassLoader() {
  62             super("MyClassLoader", null);
  63         }
  64 
  65         public final Class<?> defineClass(String name, byte[] b) {
  66             return super.defineClass(name, b, 0, b.length);
  67         }
  68     }
  69 
  70     private static final JVM jvm = JVM.getJVM();
  71     public static ClassLoader myClassLoader;
  72 
  73     public static void main(String[] args) throws Throwable {
  74         assertEventTypeNotAvailable();
  75         myClassLoader = createClassLoaderWithEventClass();
  76 
  77         try (Recording r0 = new Recording()) {
  78             r0.start();
  79             r0.stop();
  80             if (getEventType(r0, 0, EVENT_NAME) == null) {
  81                 throw new Exception("Expected event class to have corresponding event type");
  82             }
  83         }
  84 
  85         try (Recording r1 = new Recording(); Recording r2 = new Recording(); Recording r3 = new Recording()) {
  86             r1.start();
  87             r2.start();
  88             System.out.println("Class loader with name " + myClassLoader.getName() + " is on the heap");
  89             unLoadEventClass();
  90             r3.start();
  91 
  92             assertEventTypeNotAvailable();
  93             r3.stop();
  94             r2.stop();
  95             r1.stop();
  96 
  97             if (getEventType(r1, 1, EVENT_NAME) == null) {
  98                 throw new Exception("Expected event class to have corresponding event type in recording with all chunks");
  99             }
 100             if (getEventType(r2, 2, EVENT_NAME) == null) {
 101                 throw new Exception("Expected event class to have corresponding event type in recording where event class was unloaded");
 102             }
 103             if (getEventType(r3, 3, EVENT_NAME) != null) {
 104                 throw new Exception("Unexpected metadata found for event class tha has been unloaded.");
 105             }
 106         }
 107     }
 108 
 109     private static MyClassLoader createClassLoaderWithEventClass() throws Exception {
 110         String resourceName = EVENT_NAME.replace('.', '/') + ".class";
 111         try (InputStream is = TestUnloadingEventClass.class.getClassLoader().getResourceAsStream(resourceName)) {
 112             ByteArrayOutputStream baos = new ByteArrayOutputStream();
 113             byte[] buffer = new byte[4096];
 114             int byteValue = 0;
 115             while ((byteValue = is.read(buffer, 0, buffer.length)) != -1) {
 116                 baos.write(buffer, 0, byteValue);
 117             }
 118             baos.flush();
 119             MyClassLoader myClassLoader = new MyClassLoader();
 120             Class<?> eventClass = myClassLoader.defineClass(EVENT_NAME, baos.toByteArray());
 121             if (eventClass == null) {
 122                 throw new Exception("Could not define test class");
 123             }
 124             if (eventClass.getSuperclass() != Event.class) {
 125                 throw new Exception("Superclass should be jdk.jfr.Event");
 126             }
 127             if (eventClass.getSuperclass().getClassLoader() != null) {
 128                 throw new Exception("Class loader of jdk.jfr.Event should be null");
 129             }
 130             if (eventClass.getClassLoader() != myClassLoader) {
 131                 throw new Exception("Incorrect class loader for event class");
 132             }
 133             eventClass.newInstance(); // force <clinit>
 134             return myClassLoader;
 135         }
 136     }
 137 
 138     private static void unLoadEventClass() throws Exception {
 139         long firstCount = jvm.getUnloadedEventClassCount();
 140         System.out.println("Initial unloaded count: " + firstCount);
 141         myClassLoader = null;
 142         System.out.println("Cleared reference to MyClassLoader");
 143         long newCount = 0;
 144         do {
 145             System.out.println("GC triggered");
 146             System.gc();
 147             Thread.sleep(1000);
 148             newCount = jvm.getUnloadedEventClassCount();
 149             System.out.println("Unloaded count: " + newCount);
 150         } while (firstCount + 1 != newCount);
 151         System.out.println("Event class unloaded!");
 152         System.out.println("Event classes currently on the heap:");
 153         for (Class<?> eventClass : JVM.getJVM().getAllEventClasses()) {
 154             System.out.println(eventClass + " " + (eventClass.getClassLoader() != null ? eventClass.getClassLoader().getName() : null));
 155         }
 156 
 157     }
 158 
 159     private static void assertEventTypeNotAvailable() throws Exception {
 160         for (EventType type : FlightRecorder.getFlightRecorder().getEventTypes()) {
 161             if (type.getName().equals(EVENT_NAME)) {
 162                 throw new Exception("Event type should not be available");
 163             }
 164         }
 165     }
 166 
 167     private static Object getEventType(Recording r, long id, String eventName) throws IOException {
 168         Path p = Utils.createTempFile("unloading-event-class-recording-" + id + "_", ".jfr");
 169         r.dump(p);
 170         try (RecordingFile rf = new RecordingFile(p)) {
 171             for (EventType et : rf.readEventTypes()) {
 172                 if (et.getName().equals(eventName)) {
 173                     return et;
 174                 }
 175             }
 176 
 177         }
 178         return null;
 179     }
 180 }
 181