1 /*
   2  * Copyright (c) 2016, 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 /*
  25  * @test
  26  * @bug 8151486
  27  * @summary Call Class.forName() on the system classloader from a class loaded
  28  *          from a custom classloader.
  29  * @library /lib/testlibrary
  30  * @build jdk.testlibrary.Utils JarUtils
  31  * @build ClassForName ClassForNameLeak
  32  * @run main/othervm/policy=test.policy -Djava.security.manager ClassForNameLeak
  33  */
  34 
  35 import java.io.IOException;
  36 import java.lang.ref.PhantomReference;
  37 import java.lang.ref.Reference;
  38 import java.lang.ref.ReferenceQueue;
  39 import java.net.MalformedURLException;
  40 import java.net.URL;
  41 import java.net.URLClassLoader;
  42 import java.nio.file.Path;
  43 import java.nio.file.Paths;
  44 import java.util.List;
  45 import java.util.concurrent.Callable;
  46 import java.util.concurrent.ExecutorService;
  47 import java.util.concurrent.Executors;
  48 import java.util.concurrent.Future;
  49 import java.util.stream.Collectors;
  50 import java.util.stream.Stream;
  51 import jdk.testlibrary.Utils;
  52 
  53 /*
  54  * Create .jar, load ClassForName from .jar using a URLClassLoader
  55  */
  56 public class ClassForNameLeak {
  57     private static final long TIMEOUT = (long)(5000.0 * Utils.TIMEOUT_FACTOR);
  58     private static final int THREADS = 10;
  59     private static final Path jarFilePath = Paths.get("cfn.jar");
  60     private static final ReferenceQueue<ClassLoader> rq = new ReferenceQueue<>();
  61 
  62     static class TestLoader {
  63         private final PhantomReference<ClassLoader> ref;
  64         TestLoader() {
  65             this.ref = loadAndRun();
  66         }
  67 
  68         // Use a new classloader to load the ClassForName class, then run its
  69         // Runnable.
  70         PhantomReference<ClassLoader> loadAndRun() {
  71             try {
  72                 ClassLoader classLoader =
  73                     new URLClassLoader("LeakedClassLoader",
  74                         new URL[]{jarFilePath.toUri().toURL()},
  75                         ClassLoader.getPlatformClassLoader());
  76 
  77                 Class<?> loadClass = Class.forName("ClassForName", true, classLoader);
  78                 ((Runnable) loadClass.newInstance()).run();
  79 
  80                 return new PhantomReference<>(classLoader, rq);
  81             } catch (MalformedURLException|ReflectiveOperationException e) {
  82                 throw new RuntimeException(e);
  83             }
  84         }
  85 
  86         PhantomReference<ClassLoader> getRef() {
  87             return ref;
  88         }
  89     }
  90 
  91     public static void main(String... args) throws Exception {
  92         // create the JAR file
  93         setup();
  94 
  95         // Make simultaneous calls to the test method, to stress things a bit
  96         ExecutorService es = Executors.newFixedThreadPool(THREADS);
  97 
  98         List<Callable<TestLoader>> callables =
  99                 Stream.generate(() -> {
 100                     Callable<TestLoader> cprcl = TestLoader::new;
 101                     return cprcl;
 102                 }).limit(THREADS).collect(Collectors.toList());
 103 
 104         List<Future<TestLoader>> futures = es.invokeAll(callables);
 105 
 106         // Give the GC a chance to enqueue the PhantomReferences
 107         for (int i = 0; i < 10; i++) {
 108             System.gc();
 109         }
 110 
 111         // Make sure all PhantomReferences to the leaked classloader are enqueued
 112         for (int j = 0; j < futures.size(); j++) {
 113             Reference rmRef = rq.remove(TIMEOUT);
 114             if (rmRef == null) {
 115                 throw new RuntimeException("ClassLoader was never enqueued!");
 116             } else {
 117                 System.out.println("Enqueued " + rmRef);
 118             }
 119         }
 120         es.shutdown();
 121         System.out.println("All ClassLoaders successfully enqueued");
 122     }
 123 
 124     private static final String CLASSFILENAME = "ClassForName.class";
 125     private static void setup() throws IOException {
 126         String testclasses = System.getProperty("test.classes", ".");
 127 
 128         // Create a temporary .jar file containing ClassForName.class
 129         Path testClassesDir = Paths.get(testclasses);
 130         JarUtils.createJarFile(jarFilePath, testClassesDir, CLASSFILENAME);
 131     }
 132 }