| /* |
| * Copyright (c) 2003, 2004, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * @test |
| * @bug 4530538 |
| * @summary Basic unit test of |
| * RuntimeMXBean.getObjectPendingFinalizationCount() |
| * 1. GC and runFinalization() to get the current pending number |
| * 2. Create some number of objects with reference and without ref. |
| * 3. Clear all the references |
| * 4. GC and runFinalization() and the finalizable objects should |
| * be garbage collected. |
| * @author Alexei Guibadoulline and Mandy Chung |
| * |
| */ |
| |
| import java.lang.management.*; |
| |
| public class Pending { |
| final static int NO_REF_COUNT = 600; |
| final static int REF_COUNT = 600; |
| final static int TOTAL_FINALIZABLE = (NO_REF_COUNT + REF_COUNT); |
| private static int finalized = 0; |
| private static MemoryMXBean mbean |
| = ManagementFactory.getMemoryMXBean(); |
| |
| private static final String INDENT = " "; |
| private static void printFinalizerInstanceCount() { |
| if (!trace) return; |
| |
| int count = sun.misc.VM.getFinalRefCount(); |
| System.out.println(INDENT + "Finalizable object Count = " + count); |
| |
| count = sun.misc.VM.getPeakFinalRefCount(); |
| System.out.println(INDENT + "Peak Finalizable object Count = " + count); |
| } |
| |
| private static boolean trace = false; |
| public static void main(String argv[]) throws Exception { |
| if (argv.length > 0 && argv[0].equals("trace")) { |
| trace = true; |
| } |
| |
| // Turn on verbose:gc to track GC |
| mbean.setVerbose(true); |
| |
| // Clean the memory and remove all objects that are pending |
| // finalization |
| System.gc(); |
| Runtime.getRuntime().runFinalization(); |
| |
| // Let the finalizer to finish |
| try { |
| Thread.sleep(200); |
| } catch (Exception e) { |
| throw e; |
| } |
| |
| // Create a number of new objects but no references to them |
| int startCount = mbean.getObjectPendingFinalizationCount(); |
| |
| System.out.println("Number of objects pending for finalization:"); |
| System.out.println(" Before creating object: " + startCount + |
| " finalized = " + finalized); |
| printFinalizerInstanceCount(); |
| |
| for (int i = 0; i < NO_REF_COUNT; i++) { |
| new MyObject(); |
| } |
| |
| Snapshot snapshot = getSnapshot(); |
| System.out.println(" Afer creating objects with no ref: " + snapshot); |
| printFinalizerInstanceCount(); |
| |
| Object[] objs = new Object[REF_COUNT]; |
| for (int i = 0; i < REF_COUNT; i++) { |
| objs[i] = new MyObject(); |
| } |
| snapshot = getSnapshot(); |
| System.out.println(" Afer creating objects with ref: " + snapshot); |
| printFinalizerInstanceCount(); |
| |
| // Now check the expected count - GC and runFinalization will be |
| // invoked. |
| checkFinalizerCount(NO_REF_COUNT, 0); |
| |
| // Clean the memory and remove all objects that are pending |
| // finalization again |
| objs = null; |
| snapshot = getSnapshot(); |
| System.out.println("Clear all references finalized = " + snapshot); |
| printFinalizerInstanceCount(); |
| |
| checkFinalizerCount(TOTAL_FINALIZABLE, NO_REF_COUNT); |
| |
| snapshot = getSnapshot(); |
| printFinalizerInstanceCount(); |
| |
| // Check the mbean now |
| if (snapshot.curFinalized != TOTAL_FINALIZABLE) { |
| throw new RuntimeException("Wrong number of finalized objects " |
| + snapshot + ". Expected " |
| + TOTAL_FINALIZABLE); |
| } |
| |
| if (startCount != 0 || snapshot.curPending != 0) { |
| throw new RuntimeException("Wrong number of objects pending " |
| + "finalization start = " + startCount |
| + " end = " + snapshot); |
| } |
| |
| System.out.println("Test passed."); |
| } |
| |
| private static void checkFinalizerCount(int expectedTotal, int curFinalized) |
| throws Exception { |
| int prevCount = -1; |
| Snapshot snapshot = getSnapshot(); |
| if (snapshot.curFinalized != curFinalized) { |
| throw new RuntimeException( |
| "Unexpected finalized objects: " + snapshot + |
| " but expected = " + curFinalized); |
| } |
| int MAX_GC_LOOP = 6; |
| for (int i = 1; |
| snapshot.curFinalized != expectedTotal && i <= MAX_GC_LOOP; |
| i++) { |
| System.gc(); |
| |
| // Pause to give a chance to Finalizer thread to run |
| pause(); |
| |
| printFinalizerInstanceCount(); |
| // Race condition may occur; attempt to check this |
| // a few times before throwing exception. |
| for (int j = 0; j < 5; j++) { |
| // poll for another current pending count |
| snapshot = getSnapshot(); |
| if (snapshot.curFinalized == expectedTotal || |
| snapshot.curPending != 0) { |
| break; |
| } |
| } |
| System.out.println(" After GC " + i + ": " + snapshot); |
| |
| Runtime.getRuntime().runFinalization(); |
| |
| // Pause to give a chance to Finalizer thread to run |
| pause(); |
| |
| snapshot = getSnapshot(); |
| if (snapshot.curFinalized == expectedTotal && |
| snapshot.curPending != 0) { |
| throw new RuntimeException( |
| "Unexpected current number of objects pending for " + |
| "finalization: " + snapshot + " but expected = 0"); |
| } |
| |
| System.out.println(" After runFinalization " + i + ": " + snapshot); |
| printFinalizerInstanceCount(); |
| |
| try { |
| Thread.sleep(1000); |
| } catch (Exception e) { |
| throw e; |
| } |
| } |
| if (snapshot.curFinalized != expectedTotal) { |
| throw new RuntimeException( |
| "Unexpected current number of objects pending for " + |
| "finalization: " + snapshot + " but expected > 0"); |
| } |
| } |
| |
| private static Object lock = new Object(); |
| private static class MyObject { |
| Object[] dummy = new Object[10]; |
| public void finalize () { |
| synchronized (lock) { |
| finalized++; |
| } |
| } |
| } |
| |
| static class Snapshot { |
| public int curFinalized; |
| public int curPending; |
| Snapshot(int f, int p) { |
| curFinalized = f; |
| curPending = p; |
| } |
| public String toString() { |
| return "Current finalized = " + curFinalized + |
| " Current pending = " + curPending; |
| } |
| } |
| |
| private static Snapshot getSnapshot() { |
| synchronized (lock) { |
| int curCount = mbean.getObjectPendingFinalizationCount(); |
| return new Snapshot(finalized, curCount); |
| } |
| } |
| |
| private static Object pauseObj = new Object(); |
| private static void pause() { |
| // Enter lock a without blocking |
| synchronized (pauseObj) { |
| try { |
| // may need to tune this timeout for different platforms |
| pauseObj.wait(20); |
| } catch (Exception e) { |
| System.err.println("Unexpected exception."); |
| e.printStackTrace(System.err); |
| } |
| } |
| } |
| } |