1 /*

     2  * Copyright (c) 2013, 2016, 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 G1AddMetaspaceDependency

    26  * @bug 8010196

    27  * @requires vm.gc.G1

    28  * @summary Checks that we don't get locking problems when adding metaspace dependencies with the G1 update buffer monitor

    29  * @run main/othervm -XX:+UseG1GC -XX:G1UpdateBufferSize=1 G1AddMetaspaceDependency

    30  */

    31 

    32 import java.io.InputStream;

    33 

    34 public class G1AddMetaspaceDependency {

    35 

    36   static byte[] getClassBytes(String name) {

    37     byte[] b = null;

    38     try (InputStream is = ClassLoader.getSystemResourceAsStream(name)) {

    39       byte[] tmp = new byte[is.available()];

    40       is.read(tmp);

    41       b = tmp;

    42     } finally {

    43       if (b == null) {

    44         throw new RuntimeException("Unable to load class file");

    45       }

    46       return b;

    47     }

    48   }

    49 

    50   static final String a_name = G1AddMetaspaceDependency.class.getName() + "$A";

    51   static final String b_name = G1AddMetaspaceDependency.class.getName() + "$B";

    52 

    53   public static void main(String... args) throws Exception {

    54     final byte[] a_bytes = getClassBytes(a_name + ".class");

    55     final byte[] b_bytes = getClassBytes(b_name + ".class");

    56 

    57     for (int i = 0; i < 1000; i += 1) {

    58       runTest(a_bytes, b_bytes);

    59     }

    60   }

    61 

    62   static class Loader extends ClassLoader {

    63     private final String myClass;

    64     private final byte[] myBytes;

    65     private final String friendClass;

    66     private final ClassLoader friendLoader;

    67 

    68     Loader(String myClass, byte[] myBytes,

    69            String friendClass, ClassLoader friendLoader) {

    70       this.myClass = myClass;

    71       this.myBytes = myBytes;

    72       this.friendClass = friendClass;

    73       this.friendLoader = friendLoader;

    74     }

    75 

    76     Loader(String myClass, byte[] myBytes) {

    77       this(myClass, myBytes, null, null);

    78     }

    79 

    80     @Override

    81     public Class<?> loadClass(String name) throws ClassNotFoundException {

    82       Class<?> c = findLoadedClass(name);

    83       if (c != null) {

    84         return c;

    85       }

    86 

    87       if (name.equals(friendClass)) {

    88         return friendLoader.loadClass(name);

    89       }

    90 

    91       if (name.equals(myClass)) {

    92         c = defineClass(name, myBytes, 0, myBytes.length);

    93         resolveClass(c);

    94         return c;

    95       }

    96 

    97       return findSystemClass(name);

    98     }

    99 

   100   }

   101 

   102   private static void runTest(final byte[] a_bytes, final byte[] b_bytes) throws Exception {

   103     Loader a_loader = new Loader(a_name, a_bytes);

   104     Loader b_loader = new Loader(b_name, b_bytes, a_name, a_loader);

   105     Loader c_loader = new Loader(b_name, b_bytes, a_name, a_loader);

   106     Loader d_loader = new Loader(b_name, b_bytes, a_name, a_loader);

   107     Loader e_loader = new Loader(b_name, b_bytes, a_name, a_loader);

   108     Loader f_loader = new Loader(b_name, b_bytes, a_name, a_loader);

   109     Loader g_loader = new Loader(b_name, b_bytes, a_name, a_loader);

   110 

   111     Class<?> c;

   112     c = b_loader.loadClass(b_name);

   113     c = c_loader.loadClass(b_name);

   114     c = d_loader.loadClass(b_name);

   115     c = e_loader.loadClass(b_name);

   116     c = f_loader.loadClass(b_name);

   117     c = g_loader.loadClass(b_name);

   118   }

   119   public class A {

   120   }

   121   class B extends A {

   122   }

   123 }