100 lines
3.4 KiB
Java
100 lines
3.4 KiB
Java
/*
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* Copyright (c) 1997, 2005, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/* @test
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* @bug 4076287
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* @summary Invoking get on a SoftReference shouldn't pin the referent
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* @run main/othervm -ms16m -mx16m Pin
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* @author Peter Jones
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* @author Mark Reinhold
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*/
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import java.lang.ref.SoftReference;
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public class Pin {
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static final int NUM_BLOCKS = 128;
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static final int BLOCK_SIZE = 32768;
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public static void main(String[] args) throws Exception {
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SoftReference[] blocks = new SoftReference[NUM_BLOCKS];
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byte[] block;
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System.err.println("Filling array with " + NUM_BLOCKS +
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" SoftReferences to blocks of " +
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BLOCK_SIZE + " bytes.");
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for (int i = 0; i < NUM_BLOCKS; ++ i) {
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block = new byte[BLOCK_SIZE];
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SoftReference ref = new SoftReference(block);
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blocks[i] = ref;
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}
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block = null;
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System.err.println("Allowing SoftReferences to be enqueued.");
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System.gc();
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Thread.sleep(1000);
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/* -- Commenting out the following section will hide the bug -- */
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System.err.println("Invoking get() on SoftReferences.");
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for (int i = 0; i < NUM_BLOCKS; ++ i) {
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block = (byte[]) blocks[i].get();
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}
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block = null;
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/* -- end -- */
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System.err.println("Forcing desperate garbage collection...");
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java.util.Vector chain = new java.util.Vector();
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try {
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while (true) {
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System.gc();
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int[] hungry = new int[65536];
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chain.addElement(hungry);
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Thread.sleep(100); // yield, for what it's worth
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}
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} catch (OutOfMemoryError e) {
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chain = null; // Free memory for further work.
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System.err.println("Got OutOfMemoryError, as expected.");
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}
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int emptyCount = 0, fullCount = 0;
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System.err.print("Examining contents of array:");
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for (int i = 0; i < NUM_BLOCKS; ++ i) {
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block = (byte[]) blocks[i].get();
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if (block == null) {
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emptyCount++;
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} else {
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fullCount++;
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}
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}
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System.err.println(" " + emptyCount + " empty, " +
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fullCount + " full.");
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if (emptyCount == 0)
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throw new Exception("No SoftReference instances were cleared");
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}
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}
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