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/**
 * @test TestTenuredGenPoolCollectionUsage
 * @bug 8175375
 * @requires vm.gc.G1 
 * @summary Verify that MemoryPoolMXBean.getCollectionUsage() works fine with
 * -XX:+UseG1GC and -XX:+ExplicitGCInvokesConcurrent
 * @library /test/lib /
 * @modules java.base/jdk.internal.misc
 * @modules java.management/sun.management
 * @run main/othervm -XX:+ExplicitGCInvokesConcurrent -XX:+UseG1GC
 * TestTenuredGenPoolCollectionUsage
 */

import java.util.ArrayList;
import java.util.List;
import java.lang.management.ManagementFactory;
import java.lang.management.MemoryPoolMXBean;
import java.lang.management.MemoryType;
import jdk.test.lib.Asserts;

public class TestTenuredGenPoolCollectionUsage {

    public static void main(String[] args) {
        new TestTenuredGenPoolCollectionUsage().test();
    }

    private final void test() {
        MemoryPoolMXBean tenuredGenPool = null;
        List<byte[]> data = new ArrayList<>();
        for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) {
            if (pool.getType() == MemoryType.HEAP && pool.isUsageThresholdSupported()) {
                tenuredGenPool = pool;
            }
        }
        data.add(new byte[1024 * 1024 * 50]);
        try {
            Thread.sleep(100);
        } catch(InterruptedException ie) {
            ie.printStackTrace();
        }
        System.gc();
        System.out.println("Collection usage = " + tenuredGenPool.getCollectionUsage().getUsed() + ", usage = " + tenuredGenPool.getUsage().getUsed());
        Asserts.assertTrue(tenuredGenPool.getCollectionUsage().getUsed() > 0);
    }
}