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Java example source code file (TestMetaspaceMemoryPool.java)

This example Java source code file (TestMetaspaceMemoryPool.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, compressed, expected, list, management, memorymanagermxbean, memorypoolmxbean, memoryusage, metaspace, runtimeexception, testmetaspacememorypool, util, xx\:\+usecompressedoops, xx\:maxmetaspacesize

The TestMetaspaceMemoryPool.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 TestMetaspaceMemoryPool
 * @bug 8000754
 * @summary Tests that a MemoryPoolMXBeans is created for metaspace and that a
 *          MemoryManagerMXBean is created.
 * @library /testlibrary
 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-UseCompressedOops TestMetaspaceMemoryPool
 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-UseCompressedOops -XX:MaxMetaspaceSize=60m TestMetaspaceMemoryPool
 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UseCompressedOops -XX:+UseCompressedClassPointers TestMetaspaceMemoryPool
 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UseCompressedOops -XX:+UseCompressedClassPointers -XX:CompressedClassSpaceSize=60m TestMetaspaceMemoryPool
 */
public class TestMetaspaceMemoryPool {
    public static void main(String[] args) {
        verifyThatMetaspaceMemoryManagerExists();

        boolean isMetaspaceMaxDefined = InputArguments.containsPrefix("-XX:MaxMetaspaceSize");
        verifyMemoryPool(getMemoryPool("Metaspace"), isMetaspaceMaxDefined);

        if (Platform.is64bit()) {
            if (InputArguments.contains("-XX:+UseCompressedOops")) {
                MemoryPoolMXBean cksPool = getMemoryPool("Compressed Class Space");
                verifyMemoryPool(cksPool, true);
            }
        }
    }

    private static void verifyThatMetaspaceMemoryManagerExists() {
        List<MemoryManagerMXBean> managers = ManagementFactory.getMemoryManagerMXBeans();
        for (MemoryManagerMXBean manager : managers) {
            if (manager.getName().equals("Metaspace Manager")) {
                return;
            }
        }

        throw new RuntimeException("Expected to find a metaspace memory manager");
    }

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

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

    private static void verifyMemoryPool(MemoryPoolMXBean pool, boolean isMaxDefined) {
        MemoryUsage mu = pool.getUsage();
        long init = mu.getInit();
        long used = mu.getUsed();
        long committed = mu.getCommitted();
        long max = mu.getMax();

        assertGTE(init, 0L);
        assertGTE(used, init);
        assertGTE(committed, used);

        if (isMaxDefined) {
            assertGTE(max, committed);
        } else {
            assertEQ(max, -1L);
        }
    }
}

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