J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003-2004 Sun Microsystems, 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 21 | * have any questions. |
| 22 | */ |
| 23 | |
| 24 | /* |
| 25 | * @test |
| 26 | * @bug 4530538 |
| 27 | * @summary Basic unit test of |
| 28 | * RuntimeMXBean.getObjectPendingFinalizationCount() |
| 29 | * 1. GC and runFinalization() to get the current pending number |
| 30 | * 2. Create some number of objects with reference and without ref. |
| 31 | * 3. Clear all the references |
| 32 | * 4. GC and runFinalization() and the finalizable objects should |
| 33 | * be garbage collected. |
| 34 | * @author Alexei Guibadoulline and Mandy Chung |
| 35 | * |
| 36 | */ |
| 37 | |
| 38 | import java.lang.management.*; |
| 39 | |
| 40 | public class Pending { |
| 41 | final static int NO_REF_COUNT = 600; |
| 42 | final static int REF_COUNT = 600; |
| 43 | final static int TOTAL_FINALIZABLE = (NO_REF_COUNT + REF_COUNT); |
| 44 | private static int finalized = 0; |
| 45 | private static MemoryMXBean mbean |
| 46 | = ManagementFactory.getMemoryMXBean(); |
| 47 | |
| 48 | private static final String INDENT = " "; |
| 49 | private static void printFinalizerInstanceCount() { |
| 50 | if (!trace) return; |
| 51 | |
| 52 | int count = sun.misc.VM.getFinalRefCount(); |
| 53 | System.out.println(INDENT + "Finalizable object Count = " + count); |
| 54 | |
| 55 | count = sun.misc.VM.getPeakFinalRefCount(); |
| 56 | System.out.println(INDENT + "Peak Finalizable object Count = " + count); |
| 57 | } |
| 58 | |
| 59 | private static boolean trace = false; |
| 60 | public static void main(String argv[]) throws Exception { |
| 61 | if (argv.length > 0 && argv[0].equals("trace")) { |
| 62 | trace = true; |
| 63 | } |
| 64 | |
| 65 | // Turn on verbose:gc to track GC |
| 66 | mbean.setVerbose(true); |
| 67 | |
| 68 | // Clean the memory and remove all objects that are pending |
| 69 | // finalization |
| 70 | System.gc(); |
| 71 | Runtime.getRuntime().runFinalization(); |
| 72 | |
| 73 | // Let the finalizer to finish |
| 74 | try { |
| 75 | Thread.sleep(200); |
| 76 | } catch (Exception e) { |
| 77 | throw e; |
| 78 | } |
| 79 | |
| 80 | // Create a number of new objects but no references to them |
| 81 | int startCount = mbean.getObjectPendingFinalizationCount(); |
| 82 | |
| 83 | System.out.println("Number of objects pending for finalization:"); |
| 84 | System.out.println(" Before creating object: " + startCount + |
| 85 | " finalized = " + finalized); |
| 86 | printFinalizerInstanceCount(); |
| 87 | |
| 88 | for (int i = 0; i < NO_REF_COUNT; i++) { |
| 89 | new MyObject(); |
| 90 | } |
| 91 | |
| 92 | Snapshot snapshot = getSnapshot(); |
| 93 | System.out.println(" Afer creating objects with no ref: " + snapshot); |
| 94 | printFinalizerInstanceCount(); |
| 95 | |
| 96 | Object[] objs = new Object[REF_COUNT]; |
| 97 | for (int i = 0; i < REF_COUNT; i++) { |
| 98 | objs[i] = new MyObject(); |
| 99 | } |
| 100 | snapshot = getSnapshot(); |
| 101 | System.out.println(" Afer creating objects with ref: " + snapshot); |
| 102 | printFinalizerInstanceCount(); |
| 103 | |
| 104 | // Now check the expected count - GC and runFinalization will be |
| 105 | // invoked. |
| 106 | checkFinalizerCount(NO_REF_COUNT, 0); |
| 107 | |
| 108 | // Clean the memory and remove all objects that are pending |
| 109 | // finalization again |
| 110 | objs = null; |
| 111 | snapshot = getSnapshot(); |
| 112 | System.out.println("Clear all references finalized = " + snapshot); |
| 113 | printFinalizerInstanceCount(); |
| 114 | |
| 115 | checkFinalizerCount(TOTAL_FINALIZABLE, NO_REF_COUNT); |
| 116 | |
| 117 | snapshot = getSnapshot(); |
| 118 | printFinalizerInstanceCount(); |
| 119 | |
| 120 | // Check the mbean now |
| 121 | if (snapshot.curFinalized != TOTAL_FINALIZABLE) { |
| 122 | throw new RuntimeException("Wrong number of finalized objects " |
| 123 | + snapshot + ". Expected " |
| 124 | + TOTAL_FINALIZABLE); |
| 125 | } |
| 126 | |
| 127 | if (startCount != 0 || snapshot.curPending != 0) { |
| 128 | throw new RuntimeException("Wrong number of objects pending " |
| 129 | + "finalization start = " + startCount |
| 130 | + " end = " + snapshot); |
| 131 | } |
| 132 | |
| 133 | System.out.println("Test passed."); |
| 134 | } |
| 135 | |
| 136 | private static void checkFinalizerCount(int expectedTotal, int curFinalized) |
| 137 | throws Exception { |
| 138 | int prevCount = -1; |
| 139 | Snapshot snapshot = getSnapshot(); |
| 140 | if (snapshot.curFinalized != curFinalized) { |
| 141 | throw new RuntimeException( |
| 142 | "Unexpected finalized objects: " + snapshot + |
| 143 | " but expected = " + curFinalized); |
| 144 | } |
| 145 | int MAX_GC_LOOP = 6; |
| 146 | for (int i = 1; |
| 147 | snapshot.curFinalized != expectedTotal && i <= MAX_GC_LOOP; |
| 148 | i++) { |
| 149 | System.gc(); |
| 150 | |
| 151 | // Pause to give a chance to Finalizer thread to run |
| 152 | pause(); |
| 153 | |
| 154 | printFinalizerInstanceCount(); |
| 155 | // Race condition may occur; attempt to check this |
| 156 | // a few times before throwing exception. |
| 157 | for (int j = 0; j < 5; j++) { |
| 158 | // poll for another current pending count |
| 159 | snapshot = getSnapshot(); |
| 160 | if (snapshot.curFinalized == expectedTotal || |
| 161 | snapshot.curPending != 0) { |
| 162 | break; |
| 163 | } |
| 164 | } |
| 165 | System.out.println(" After GC " + i + ": " + snapshot); |
| 166 | |
| 167 | Runtime.getRuntime().runFinalization(); |
| 168 | |
| 169 | // Pause to give a chance to Finalizer thread to run |
| 170 | pause(); |
| 171 | |
| 172 | snapshot = getSnapshot(); |
| 173 | if (snapshot.curFinalized == expectedTotal && |
| 174 | snapshot.curPending != 0) { |
| 175 | throw new RuntimeException( |
| 176 | "Unexpected current number of objects pending for " + |
| 177 | "finalization: " + snapshot + " but expected = 0"); |
| 178 | } |
| 179 | |
| 180 | System.out.println(" After runFinalization " + i + ": " + snapshot); |
| 181 | printFinalizerInstanceCount(); |
| 182 | |
| 183 | try { |
| 184 | Thread.sleep(1000); |
| 185 | } catch (Exception e) { |
| 186 | throw e; |
| 187 | } |
| 188 | } |
| 189 | if (snapshot.curFinalized != expectedTotal) { |
| 190 | throw new RuntimeException( |
| 191 | "Unexpected current number of objects pending for " + |
| 192 | "finalization: " + snapshot + " but expected > 0"); |
| 193 | } |
| 194 | } |
| 195 | |
| 196 | private static Object lock = new Object(); |
| 197 | private static class MyObject { |
| 198 | Object[] dummy = new Object[10]; |
| 199 | public void finalize () { |
| 200 | synchronized (lock) { |
| 201 | finalized++; |
| 202 | } |
| 203 | } |
| 204 | } |
| 205 | |
| 206 | static class Snapshot { |
| 207 | public int curFinalized; |
| 208 | public int curPending; |
| 209 | Snapshot(int f, int p) { |
| 210 | curFinalized = f; |
| 211 | curPending = p; |
| 212 | } |
| 213 | public String toString() { |
| 214 | return "Current finalized = " + curFinalized + |
| 215 | " Current pending = " + curPending; |
| 216 | } |
| 217 | } |
| 218 | |
| 219 | private static Snapshot getSnapshot() { |
| 220 | synchronized (lock) { |
| 221 | int curCount = mbean.getObjectPendingFinalizationCount(); |
| 222 | return new Snapshot(finalized, curCount); |
| 223 | } |
| 224 | } |
| 225 | |
| 226 | private static Object pauseObj = new Object(); |
| 227 | private static void pause() { |
| 228 | // Enter lock a without blocking |
| 229 | synchronized (pauseObj) { |
| 230 | try { |
| 231 | // may need to tune this timeout for different platforms |
| 232 | pauseObj.wait(20); |
| 233 | } catch (Exception e) { |
| 234 | System.err.println("Unexpected exception."); |
| 235 | e.printStackTrace(System.err); |
| 236 | } |
| 237 | } |
| 238 | } |
| 239 | } |