jdk

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/*
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 * Copyright (c) 2015, 2019, 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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package gc;
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/*
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 * @test TestDisableExplicitGC
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 * @requires vm.opt.DisableExplicitGC == null
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 * @requires vm.compMode != "Xcomp"
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 * @summary Verify GC behavior with DisableExplicitGC flag.
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 * @library /test/lib
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 * @modules java.base/jdk.internal.misc
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 * @modules jdk.management/com.sun.management.internal
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 * @run main/othervm                             -Xlog:gc=debug gc.TestDisableExplicitGC
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 * @run main/othervm/fail -XX:+DisableExplicitGC -Xlog:gc=debug gc.TestDisableExplicitGC
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 * @run main/othervm      -XX:-DisableExplicitGC -Xlog:gc=debug gc.TestDisableExplicitGC
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 */
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import java.lang.management.GarbageCollectorMXBean;
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import java.util.List;
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import static jdk.test.lib.Asserts.*;
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public class TestDisableExplicitGC {
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    public static void main(String[] args) throws InterruptedException {
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        List<GarbageCollectorMXBean> list = java.lang.management.ManagementFactory.getGarbageCollectorMXBeans();
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        long collectionCountBefore = getCollectionCount(list);
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        System.gc();
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        long collectionCountAfter = getCollectionCount(list);
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        assertLT(collectionCountBefore, collectionCountAfter);
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    }
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    private static long getCollectionCount(List<GarbageCollectorMXBean> list) {
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        int collectionCount = 0;
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        for (GarbageCollectorMXBean gcMXBean : list) {
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            collectionCount += gcMXBean.getCollectionCount();
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        }
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        return collectionCount;
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    }
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}
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