1 /*
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23 
24 /*
25  * @test TestDisableExplicitGC
26  * @requires vm.opt.DisableExplicitGC == null
27  * @summary Verify GC behavior with DisableExplicitGC flag.
28  * @library /test/lib
29  * @modules java.base/jdk.internal.misc
30  * @modules jdk.management/com.sun.management.internal
31  * @run main/othervm                             -Xlog:gc=debug TestDisableExplicitGC
32  * @run main/othervm/fail -XX:+DisableExplicitGC -Xlog:gc=debug TestDisableExplicitGC
33  * @run main/othervm      -XX:-DisableExplicitGC -Xlog:gc=debug TestDisableExplicitGC
34  */
35 import java.lang.management.GarbageCollectorMXBean;
36 import java.util.List;
37 import static jdk.test.lib.Asserts.*;
38 
39 public class TestDisableExplicitGC {
40 
main(String[] args)41     public static void main(String[] args) throws InterruptedException {
42         List<GarbageCollectorMXBean> list = java.lang.management.ManagementFactory.getGarbageCollectorMXBeans();
43         long collectionCountBefore = getCollectionCount(list);
44         System.gc();
45         long collectionCountAfter = getCollectionCount(list);
46         assertLT(collectionCountBefore, collectionCountAfter);
47     }
48 
getCollectionCount(List<GarbageCollectorMXBean> list)49     private static long getCollectionCount(List<GarbageCollectorMXBean> list) {
50         int collectionCount = 0;
51         for (GarbageCollectorMXBean gcMXBean : list) {
52             collectionCount += gcMXBean.getCollectionCount();
53         }
54         return collectionCount;
55     }
56 }
57