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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 *

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/*

 * @test

 * @bug     4982301

 * @summary Sanity Test for GarbageCollectorMXBean.getLastGcInfo().

 * @author  Mandy Chung

 *

 * @run main/othervm -XX:-ExplicitGCInvokesConcurrent LastGCInfo

 */

// Passing "-XX:-ExplicitGCInvokesConcurrent" to force System.gc()

// run on foreground when CMS is used and prevent situations when "GcInfo"

// is missing even though System.gc() was successfuly processed.

import java.lang.management.ManagementFactory;

import java.lang.management.MemoryUsage;

import java.lang.management.MemoryPoolMXBean;

import java.util.*;

import com.sun.management.GcInfo;

import com.sun.management.GarbageCollectorMXBean;

public class LastGCInfo {

    public static void main(String[] argv) throws Exception {

        boolean hasGcInfo = false;

        System.gc();

        List mgrs = ManagementFactory.getGarbageCollectorMXBeans();

        for (ListIterator iter = mgrs.listIterator(); iter.hasNext(); ) {

            Object mgr = iter.next();

            if (mgr instanceof GarbageCollectorMXBean) {

                GarbageCollectorMXBean gc = (GarbageCollectorMXBean) mgr;

                GcInfo info = gc.getLastGcInfo();

                if (info != null) {

                    checkGcInfo(gc.getName(), info);

                    hasGcInfo = true;

                }

            }

        }

        if (! hasGcInfo) {

            throw new RuntimeException("No GcInfo returned");

        }

        System.out.println("Test passed.");

    }

    private static void checkGcInfo(String name, GcInfo info) throws Exception {

        System.out.println("GC statistic for : " + name);

        System.out.print("GC #" + info.getId());

        System.out.print(" start:" + info.getStartTime());

        System.out.print(" end:" + info.getEndTime());

        System.out.println(" (" + info.getDuration() + "ms)");

        Map usage = info.getMemoryUsageBeforeGc();

        List pnames = new ArrayList();

        for (Iterator iter = usage.entrySet().iterator(); iter.hasNext(); ) {

            Map.Entry entry = (Map.Entry) iter.next();

            String poolname = (String) entry.getKey();

            pnames.add(poolname);

            MemoryUsage busage = (MemoryUsage) entry.getValue();

            MemoryUsage ausage = (MemoryUsage) info.getMemoryUsageAfterGc().get(poolname);

            if (ausage == null) {

                throw new RuntimeException("After Gc Memory does not exist" +

                    " for " + poolname);

            }

            System.out.println("Usage for pool " + poolname);

            System.out.println("   Before GC: " + busage);

            System.out.println("   After GC: " + ausage);

        }

        // check if memory usage for all memory pools are returned

        List pools = ManagementFactory.getMemoryPoolMXBeans();

        for (Iterator iter = pools.iterator(); iter.hasNext(); ) {

            MemoryPoolMXBean p = (MemoryPoolMXBean) iter.next();

            if (!pnames.contains(p.getName())) {

                throw new RuntimeException("GcInfo does not contain " +

                    "memory usage for pool " + p.getName());

            }

        }

    }

}