1 /*
   2  * Copyright (c) 2013, 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.event.runtime;
  27 
  28 import java.time.Duration;
  29 import java.util.List;
  30 
  31 import jdk.jfr.Recording;
  32 import jdk.jfr.consumer.RecordedClass;
  33 import jdk.jfr.consumer.RecordedClassLoader;
  34 import jdk.jfr.consumer.RecordedEvent;
  35 import jdk.test.lib.Asserts;
  36 import jdk.test.lib.jfr.EventNames;
  37 import jdk.test.lib.jfr.Events;
  38 import jdk.test.lib.jfr.TestClassLoader;
  39 
  40 /**
  41  * @test
  42  * @summary The test verifies that a class unload event is created when class is unloaded
  43  * @key jfr
  44  *
  45  * @library /lib /
  46  * @build jdk.jfr.event.runtime.TestClasses
  47  * @run main/othervm -XX:+PrintGCDetails -XX:+PrintGC  -verbose:class -Xmx16m jdk.jfr.event.runtime.TestClassUnloadEvent
  48  */
  49 
  50 /**
  51  * System.gc() will trigger class unloading if -XX:+ExplicitGCInvokesConcurrent is NOT set.
  52  * If this flag is set G1 will never unload classes on System.gc() and
  53  * CMS will not guarantee that all semantically dead classes will be unloaded.
  54  * As far as the "jfr" key guarantees no VM flags are set from the outside
  55  * it should be enough with System.gc().
  56  */
  57 public final class TestClassUnloadEvent {
  58     private final static String TEST_CLASS_NAME = "jdk.jfr.event.runtime.TestClasses";
  59     private final static String EVENT_PATH = EventNames.ClassUnload;
  60 
  61     // Declare unloadableClassLoader as "public static"
  62     // to prevent the compiler to optimize away all unread writes
  63     public static TestClassLoader unloadableClassLoader;
  64 
  65     public static void main(String[] args) throws Throwable {
  66         Recording recording = new Recording();
  67         recording.enable(EVENT_PATH).withThreshold(Duration.ofMillis(0));
  68         unloadableClassLoader = new TestClassLoader();
  69         recording.start();
  70         unloadableClassLoader.loadClass(TEST_CLASS_NAME);
  71         unloadableClassLoader = null;
  72         System.gc();
  73         recording.stop();
  74 
  75         List<RecordedEvent> events = Events.fromRecording(recording);
  76         Events.hasEvents(events);
  77         boolean isAnyFound = false;
  78         for (RecordedEvent event : events) {
  79             System.out.println("Event:" + event);
  80             RecordedClass unloadedClass = event.getValue("unloadedClass");
  81             if (TEST_CLASS_NAME.equals(unloadedClass.getName())) {
  82                 RecordedClassLoader definingClassLoader = unloadedClass.getClassLoader();
  83                 Asserts.assertEquals(TestClassLoader.class.getName(), definingClassLoader.getType().getName(),
  84                     "Expected " + TestClassLoader.class.getName() + ", got " + definingClassLoader.getType().getName());
  85                 //Asserts.assertEquals(TestClassLoader.CLASS_LOADER_NAME, definingClassLoader.getName(),
  86                   //  "Expected " + TestClassLoader.CLASS_LOADER_NAME + ", got " + definingClassLoader.getName());
  87                 Asserts.assertFalse(isAnyFound, "Found more than 1 event");
  88                 isAnyFound = true;
  89             }
  90         }
  91         Asserts.assertTrue(isAnyFound, "No events found");
  92     }
  93 }