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.util.List;
  29 
  30 import jdk.jfr.Recording;
  31 import jdk.jfr.consumer.RecordedEvent;
  32 import jdk.test.lib.Asserts;
  33 import jdk.test.lib.jfr.EventNames;
  34 import jdk.test.lib.jfr.Events;
  35 import jdk.test.lib.jfr.TestClassLoader;
  36 
  37 /**
  38  * @test
  39  * @key jfr
  40  *
  41  * @library /lib /
  42  * @build jdk.jfr.event.runtime.TestClasses
  43  * @run main/othervm jdk.jfr.event.runtime.TestClassLoadingStatisticsEvent
  44  */
  45 /**
  46  * This test will load a number of classes. After each load step we verify that
  47  * the loadedClassCount and unloadedClassCount attributes are correct.
  48  *
  49  * System.gc() will trigger class unloading if -XX:+ExplicitGCInvokesConcurrent
  50  * is NOT set. If this flag is set G1 will never unload classes on System.gc()
  51  * and CMS will not guarantee that all semantically dead classes will be
  52  * unloaded. As far as the "jfr" key guarantees no VM flags are set from the
  53  * outside it should be enough with System.gc().
  54  */
  55 public class TestClassLoadingStatisticsEvent {
  56 
  57     private final static String EVENT_PATH = EventNames.ClassLoadingStatistics;
  58     private final static String TESTCLASS_PUBLIC_STATIC =
  59                 "jdk.jfr.event.runtime.TestClasses$TestClassPublicStatic";
  60     private final static String TESTCLASS_PUBLIC_STATIC_INNER =
  61                 "jdk.jfr.event.runtime.TestClasses$TestClassPublicStatic$TestClassPublicStaticInner";
  62 
  63     // Declare unloadableClassLoader as "public static"
  64     // to prevent the compiler to optimize away all unread writes
  65     public static TestClassLoader unloadableClassLoader;
  66 
  67     public static void main(String[] args) throws Throwable {
  68         // Load twice to get more stable result.
  69         RecordedEvent event = getCurrentEvent();
  70         event = getCurrentEvent();
  71 
  72         // Declare class ClassLoadingStatisticsHelper.
  73         TestClasses[] helpers = new TestClasses[10];
  74         event = verifyCountDelta(event, 1, 0);
  75 
  76         // Should load classes TestClassPrivate and TestClassPrivateStatic.
  77         for (int c = 0; c < helpers.length; c++) {
  78             helpers[c] = new TestClasses();
  79         }
  80         event = verifyCountDelta(event, 2, 0);
  81 
  82         // Load classes TestClassProtected and B2.
  83         helpers[0].new TestClassProtected();
  84         helpers[1].new TestClassProtected(); // This class is already loaded.
  85         new TestClasses.TestClassProtectedStatic();
  86         event = verifyCountDelta(event, 2, 0);
  87 
  88         // Load classes TestClassProtected1 and TestClassProtectedStatic1.
  89         for (int c = 0; c < helpers.length; c++) {
  90             helpers[c].loadClasses();
  91         }
  92         event = verifyCountDelta(event, 2, 0);
  93 
  94         // Load the classes with separate class loader. Will be unloaded later.
  95         unloadableClassLoader = new TestClassLoader();
  96 
  97         unloadableClassLoader.loadClass(TESTCLASS_PUBLIC_STATIC_INNER);
  98         event = verifyCountDelta(event, 1, 0);
  99 
 100         unloadableClassLoader.loadClass(TESTCLASS_PUBLIC_STATIC);
 101         event = verifyCountDelta(event, 1, 0);
 102 
 103         // This System.gc() should not unload classes, since the
 104         // unloadableClassLoader object is still active.
 105         System.gc();
 106         event = verifyCountDelta(event, 0, 0);
 107 
 108         // make classes are unloaded.
 109         unloadableClassLoader = null;
 110         System.gc();
 111         event = verifyCountDelta(event, 0, 2);
 112     }
 113 
 114     private static RecordedEvent getCurrentEvent() throws Throwable {
 115         Recording recording = new Recording();
 116         recording.enable(EVENT_PATH);
 117         recording.start();
 118         recording.stop();
 119         List<RecordedEvent> events = Events.fromRecording(recording);
 120         Asserts.assertFalse(events.isEmpty(), "No events in recording");
 121         RecordedEvent event = events.get(0);
 122         return event;
 123     }
 124 
 125     private static RecordedEvent verifyCountDelta(
 126         RecordedEvent prevEvent, int loadDelta, int unloadDelta) throws Throwable {
 127         RecordedEvent currEvent = null;
 128         try {
 129             long prevLoad = Events.assertField(prevEvent, "loadedClassCount").getValue();
 130             long prevUnload = Events.assertField(prevEvent, "unloadedClassCount").getValue();
 131 
 132             currEvent = getCurrentEvent();
 133             Events.assertField(currEvent, "loadedClassCount").atLeast(prevLoad + loadDelta);
 134             Events.assertField(currEvent, "unloadedClassCount").atLeast(prevUnload + unloadDelta);
 135             return currEvent;
 136         } catch (Throwable t) {
 137             System.out.println("verifyCountDelta failed. prevEvent=" + prevEvent + ", currEvent=" + currEvent);
 138             throw t;
 139         }
 140     }
 141 
 142 }