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Java example source code file (TestPerfCountersAndMemoryPools.java)

This example Java source code file (TestPerfCountersAndMemoryPools.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

class, exception, excpted, list, management, memorypoolmxbean, metaspace, runtimeexception, string, testperfcountersandmemorypools, util, xx\:\+usecompressedklasspointers

The TestPerfCountersAndMemoryPools.java Java example source code

/*
 * Copyright (c) 2013, 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.
 */

import java.util.List;
import java.lang.management.*;

import com.oracle.java.testlibrary.*;
import static com.oracle.java.testlibrary.Asserts.*;

/* @test TestPerfCountersAndMemoryPools
 * @bug 8023476
 * @library /testlibrary
 * @summary Tests that a MemoryPoolMXBeans and PerfCounters for metaspace
 *          report the same data.
 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-UseCompressedOops -XX:-UseCompressedKlassPointers -XX:+UseSerialGC -XX:+UsePerfData -Xint TestPerfCountersAndMemoryPools
 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UseCompressedOops -XX:+UseCompressedKlassPointers -XX:+UseSerialGC -XX:+UsePerfData -Xint TestPerfCountersAndMemoryPools
 */
public class TestPerfCountersAndMemoryPools {
    public static void main(String[] args) throws Exception {
        checkMemoryUsage("Metaspace", "sun.gc.metaspace");

        if (InputArguments.contains("-XX:+UseCompressedKlassPointers") && Platform.is64bit()) {
            checkMemoryUsage("Compressed Class Space", "sun.gc.compressedclassspace");
        }
    }

    private static MemoryPoolMXBean getMemoryPool(String memoryPoolName) {
        List<MemoryPoolMXBean> pools = ManagementFactory.getMemoryPoolMXBeans();
        for (MemoryPoolMXBean pool : pools) {
            if (pool.getName().equals(memoryPoolName)) {
                return pool;
            }
        }

        throw new RuntimeException("Excpted to find a memory pool with name " +
                                   memoryPoolName);
    }

    private static void checkMemoryUsage(String memoryPoolName, String perfNS)
        throws Exception {
        MemoryPoolMXBean pool = getMemoryPool(memoryPoolName);

        // Must do a GC to update performance counters
        System.gc();
        assertEQ(getMinCapacity(perfNS), pool.getUsage().getInit());

        // Must do a second GC to update the perfomance counters again, since
        // the call pool.getUsage().getInit() could have allocated some
        // metadata.
        System.gc();
        assertEQ(getUsed(perfNS), pool.getUsage().getUsed());
        assertEQ(getCapacity(perfNS), pool.getUsage().getCommitted());
    }

    private static long getMinCapacity(String ns) throws Exception {
        return PerfCounters.findByName(ns + ".minCapacity").longValue();
    }

    private static long getCapacity(String ns) throws Exception {
        return PerfCounters.findByName(ns + ".capacity").longValue();
    }

    private static long getUsed(String ns) throws Exception {
        return PerfCounters.findByName(ns + ".used").longValue();
    }
}

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