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 
  25 /*
  26  * @test
  27  * @modules java.base/jdk.internal.misc
  28  *
  29  * @summary converted from VM Testbase vm/mlvm/anonloader/func/isGarbageCollected.
  30  * VM Testbase keywords: [feature_mlvm]
  31  * VM Testbase readme:
  32  * DESCRIPTION
  33  *     Load an anonymous class, drop all references to it and verify that it is collected
  34  *     by GC afterwards (call System.gc() just in case). PhantomReference is used to
  35  *     check that the anonymous class is gone.
  36  *
  37  * @library /vmTestbase
  38  *          /test/lib
  39  * @run driver jdk.test.lib.FileInstaller . .
  40  *
  41  * @comment build test class and indify classes
  42  * @build vm.mlvm.anonloader.func.isGarbageCollected.Test
  43  * @run driver vm.mlvm.share.IndifiedClassesBuilder
  44  *
  45  * @run main/othervm vm.mlvm.anonloader.func.isGarbageCollected.Test
  46  */
  47 
  48 package vm.mlvm.anonloader.func.isGarbageCollected;
  49 
  50 import java.lang.ref.PhantomReference;
  51 import java.lang.ref.Reference;
  52 import java.lang.ref.ReferenceQueue;
  53 
  54 import vm.mlvm.anonloader.share.AnonkTestee01;
  55 import vm.mlvm.share.MlvmTest;
  56 import vm.share.FileUtils;
  57 import vm.share.UnsafeAccess;
  58 
  59 public class Test extends MlvmTest {
  60     private static final Class<?> PARENT = AnonkTestee01.class;
  61 
  62     public boolean run() throws Exception {
  63         ReferenceQueue<Class<?>> refQueue = new ReferenceQueue<Class<?>>();
  64         PhantomReference<Class<?>> anonClassRef = createClass(refQueue);
  65         System.gc();
  66         Reference<? extends Class<?>> deletedObject = refQueue.remove();
  67         return anonClassRef.equals(deletedObject);
  68     }
  69 
  70     // a private method is great to keep anonClass reference local to make it GCed on the next cycle
  71     private PhantomReference<Class<?>> createClass(ReferenceQueue<Class<?>> refQueue) throws Exception {
  72         byte[] classBytes = FileUtils.readClass(PARENT.getName());
  73         Class<?> anonClass = UnsafeAccess.unsafe.defineAnonymousClass(PARENT,
  74                 classBytes, null);
  75         return new PhantomReference<Class<?>>(anonClass, refQueue);
  76     }
  77 
  78     public static void main(String[] args) { MlvmTest.launch(args); }
  79 }