1 /*
   2  * Copyright (c) 2019, Red Hat, Inc. 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 package gc.epsilon;
  25 
  26 /**
  27  * @test TestClasses
  28  * @requires vm.gc.Epsilon
  29  * @summary Epsilon is able to allocate a lot of classes
  30  *
  31  * @modules java.base/jdk.internal.org.objectweb.asm
  32  *          java.base/jdk.internal.misc
  33  *
  34  * @run main/othervm -Xmx128m -XX:MetaspaceSize=1m -XX:MaxMetaspaceSize=64m -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -Xlog:gc -Xlog:gc+metaspace gc.epsilon.TestClasses
  35  */
  36 
  37 import jdk.internal.org.objectweb.asm.ClassWriter;
  38 import jdk.internal.org.objectweb.asm.Opcodes;
  39 
  40 import java.util.*;
  41 import java.io.*;
  42 import java.nio.*;
  43 import java.nio.file.*;
  44 
  45 public class TestClasses {
  46 
  47   static final int COUNT = 32*1024;
  48 
  49   static volatile Object sink;
  50 
  51   static class MyClassLoader extends ClassLoader {
  52     public byte[] createClass(String name) {
  53       ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
  54       cw.visit(Opcodes.V1_8, Opcodes.ACC_PUBLIC | Opcodes.ACC_SUPER, name, null, "java/lang/Object", null);
  55       return cw.toByteArray();
  56     }
  57 
  58     public Class<?> loadClass(String name) throws ClassNotFoundException {
  59       if (!name.startsWith("Dummy")) {
  60         return super.loadClass(name);
  61       }
  62       byte[] cls = createClass(name);
  63       return defineClass(name, cls, 0, cls.length, null);
  64     }
  65   }
  66 
  67   public static void main(String[] args) throws Exception {
  68     ClassLoader cl = new MyClassLoader();
  69     for (int c = 0; c < COUNT; c++) {
  70       Class<?> clazz = Class.forName("Dummy" + c, true, cl);
  71       if (clazz.getClassLoader() != cl) {
  72         throw new IllegalStateException("Should have loaded by target loader");
  73       }
  74       sink = c;
  75     }
  76   }
  77 }