1/* 2 * Copyright (c) 2015, 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 24import java.util.concurrent.TimeUnit; 25import java.util.concurrent.locks.Condition; 26import java.util.concurrent.locks.ReentrantLock; 27 28import java.lang.reflect.Method; 29import java.lang.reflect.Field; 30 31/* 32 * @test 33 * @summary Unit test for FinalizerHistogram 34 * @modules java.base/java.lang.ref:open 35 * @run main FinalizerHistogramTest 36 */ 37 38public class FinalizerHistogramTest { 39 static ReentrantLock lock = new ReentrantLock(); 40 static volatile int wasInitialized = 0; 41 static volatile int wasTrapped = 0; 42 static final int objectsCount = 1000; 43 44 static class MyObject { 45 public MyObject() { 46 // Make sure object allocation/deallocation is not optimized out 47 wasInitialized += 1; 48 } 49 50 protected void finalize() { 51 // Trap the object in a finalization queue 52 wasTrapped += 1; 53 lock.lock(); 54 } 55 } 56 57 public static void main(String[] argvs) { 58 try { 59 lock.lock(); 60 for(int i = 0; i < objectsCount; ++i) { 61 new MyObject(); 62 } 63 System.out.println("Objects intialized: " + objectsCount); 64 System.gc(); 65 while(wasTrapped < 1); 66 67 Class<?> klass = Class.forName("java.lang.ref.FinalizerHistogram"); 68 69 Method m = klass.getDeclaredMethod("getFinalizerHistogram"); 70 m.setAccessible(true); 71 Object entries[] = (Object[]) m.invoke(null); 72 73 Class<?> entryKlass = Class.forName("java.lang.ref.FinalizerHistogram$Entry"); 74 Field name = entryKlass.getDeclaredField("className"); 75 name.setAccessible(true); 76 Field count = entryKlass.getDeclaredField("instanceCount"); 77 count.setAccessible(true); 78 79 System.out.println("Unreachable instances waiting for finalization"); 80 System.out.println("#instances class name"); 81 System.out.println("-----------------------"); 82 83 boolean found = false; 84 for (Object entry : entries) { 85 Object e = entryKlass.cast(entry); 86 System.out.printf("%10d %s\n", count.get(e), name.get(e)); 87 if (((String) name.get(e)).indexOf("MyObject") != -1 ) { 88 found = true; 89 } 90 } 91 92 if (!found) { 93 throw new RuntimeException("MyObject is not found in test output"); 94 } 95 96 System.out.println("Test PASSED"); 97 } catch(Exception e) { 98 System.err.println("Test failed with " + e); 99 e.printStackTrace(System.err); 100 throw new RuntimeException("Test failed"); 101 } finally { 102 lock.unlock(); 103 } 104 } 105} 106