1 /*
   2  * Copyright (c) 2010, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 import java.io.BufferedReader;
  25 import java.io.InputStream;
  26 import java.io.InputStreamReader;
  27 
  28 import static jdk.test.lib.Asserts.assertGreaterThan;
  29 import jdk.test.lib.process.ProcessTools;
  30 
  31 import com.sun.tools.attach.AttachNotSupportedException;
  32 import com.sun.tools.attach.VirtualMachine;
  33 
  34 import sun.tools.attach.HotSpotVirtualMachine;
  35 
  36 /*
  37  * @test
  38  * @bug 6942989
  39  * @summary Check for WeakReference leak in Logger and anonymous Logger objects
  40  * @library /test/lib
  41  * @modules jdk.attach/sun.tools.attach
  42  *          java.logging
  43  * @build jdk.test.lib.process.ProcessTools
  44  * @run main/othervm -Djdk.attach.allowAttachSelf TestLoggerWeakRefLeak Logger
  45  * @run main/othervm -Djdk.attach.allowAttachSelf TestLoggerWeakRefLeak AnonymousLogger
  46  */
  47 public class TestLoggerWeakRefLeak {
  48 
  49     private static final String TARGET_CLASS = "java.lang.ref.WeakReference";
  50     private static final int INSTANCE_COUNT = 100;
  51     private static int loggerCount = 0;
  52 
  53     public static void main(String[] args) throws Exception {
  54         if (args[0].equals("AnonymousLogger")) {
  55             System.out.println("Test for WeakReference leak in AnonymousLogger object");
  56             testIfLeaking(TestLoggerWeakRefLeak::callAnonymousLogger);
  57         } else {
  58             System.out.println("Test for WeakReference leak in Logger object");
  59             testIfLeaking(TestLoggerWeakRefLeak::callLogger);
  60         }
  61     }
  62 
  63     /**
  64      * For these particular WeakReference leaks, the count was always observed
  65      * to be increasing so if decreasing or the same count is observed,
  66      * then there is no leak.
  67      */
  68     private static void testIfLeaking(Runnable callLogger) throws Exception {
  69         long count = 0;
  70         int instanceCount = 0;
  71         int previousInstanceCount = 0;
  72         int increasingCount = 0;
  73         int decreasingCount = 0;
  74 
  75         while (true) {
  76             callLogger.run();
  77             count += INSTANCE_COUNT;
  78 
  79             if ((count % 1000) == 0) {
  80                 System.out.println("call count = " + count);
  81 
  82                 instanceCount = getInstanceCountFromHeapHisto();
  83                 if (instanceCount > previousInstanceCount) {
  84                     increasingCount++;
  85                 } else {
  86                     decreasingCount++;
  87                     System.out.println("increasing count: " + increasingCount);
  88                     System.out.println("decreasing or the same count: " + decreasingCount);
  89                     System.out.println("Test passed: decreasing or the same instance count is observed");
  90                     break;
  91                 }
  92                 previousInstanceCount = instanceCount;
  93             }
  94 
  95             delayExecution();
  96         }
  97     }
  98 
  99     /**
 100      * This Logger call is leaking two different WeakReferences:
 101      * - one in LogManager.LogNode
 102      * - one in Logger.kids
 103      */
 104     private static void callLogger() {
 105         for (int i = 0; i < INSTANCE_COUNT; i++) {
 106             java.util.logging.Logger.getLogger("logger-" + loggerCount);
 107             if (++loggerCount >= 25000) {
 108                 // Limit the Logger namespace used by the test so the weak refs
 109                 // in LogManager.loggers that are being properly managed
 110                 // don't skew the counts by too much.
 111                 loggerCount = 0;
 112             }
 113         }
 114     }
 115 
 116     /**
 117      * This Logger call is leaking a WeakReference in Logger.kids
 118      */
 119     private static void callAnonymousLogger() {
 120         for (int i = 0; i < INSTANCE_COUNT; i++) {
 121             java.util.logging.Logger.getAnonymousLogger();
 122         }
 123     }
 124 
 125     /**
 126      * 'vm.heapHisto("-live")' will request a full GC
 127      */
 128     private static int getInstanceCountFromHeapHisto() throws AttachNotSupportedException, Exception {
 129         int instanceCount = 0;
 130 
 131         HotSpotVirtualMachine vm = (HotSpotVirtualMachine) VirtualMachine
 132                 .attach(Long.toString(ProcessTools.getProcessId()));
 133         try {
 134             try (InputStream heapHistoStream = vm.heapHisto("-live");
 135                     BufferedReader in = new BufferedReader(new InputStreamReader(heapHistoStream))) {
 136                 String inputLine;
 137                 while ((inputLine = in.readLine()) != null) {
 138                     if (inputLine.contains(TARGET_CLASS)) {
 139                         instanceCount = Integer.parseInt(inputLine
 140                                 .split("[ ]+")[2]);
 141                         System.out.println("instance count: " + instanceCount);
 142                         break;
 143                     }
 144                 }
 145             }
 146         } finally {
 147             vm.detach();
 148         }
 149 
 150         assertGreaterThan(instanceCount, 0, "No instances of " + TARGET_CLASS + " are found");
 151 
 152         return instanceCount;
 153     }
 154 
 155     /**
 156      * Delay for 1/10 of a second to avoid CPU saturation
 157      */
 158     private static void delayExecution() {
 159         try {
 160             Thread.sleep(100);
 161         } catch (InterruptedException ie) {
 162             // Ignore any exceptions
 163         }
 164     }
 165 
 166 }