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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * 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).
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 * 2 along with this work; if not, write to the Free Software Foundation,
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/*
 * @test
 * @bug 8143157
 * @summary vmoperation=debug should have logging output
 * @requires vm.flagless
 * @library /test/lib
 * @modules java.base/jdk.internal.misc
 *          java.management
 * @run driver VMOperationTest
 */

import java.lang.ref.WeakReference;
import jdk.test.lib.process.OutputAnalyzer;
import jdk.test.lib.process.ProcessTools;

public class VMOperationTest {
    public static void main(String[] args) throws Exception {
        ProcessBuilder pb = ProcessTools.createLimitedTestJavaProcessBuilder("-Xlog:vmoperation=debug",
                                                                             "-Xmx128m",
                                                                             "-Xms128m",
                                                                             InternalClass.class.getName());
        OutputAnalyzer output = new OutputAnalyzer(pb.start());
        output.shouldContain("VM_Operation (");
        output.shouldHaveExitValue(0);
    }

    public static class InternalClass {
        public static byte[] garbage;
        public static volatile WeakReference<Object> weakref;

        public static void createweakref() {
            Object o = new Object();
            weakref = new WeakReference<>(o);
        }

        // Loop until a GC runs.
        public static void main(String[] args) throws Exception {
            createweakref();
            while (weakref.get() != null) {
                garbage = new byte[8192];
                System.gc();
            }
        }
    }
}