SystemGCOnForegroundCollector.java

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/**
 * @test SystemGCOnForegroundCollector
 * @summary CMS: Call reset_after_compaction() only if a compaction has been done
 * @bug 8013184
 * @key gc
 * @key regression
 * @library /testlibrary
 * @run main/othervm SystemGCOnForegroundCollector
 * @author [email protected]
 */

import com.oracle.java.testlibrary.*;

public class SystemGCOnForegroundCollector {
  public static void main(String args[]) throws Exception {

    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
      "-showversion",
      "-XX:+UseConcMarkSweepGC",
      "-XX:MaxTenuringThreshold=1",
      "-XX:-UseCMSCompactAtFullCollection",
      ThreePlusMSSystemGC.class.getName()
      );

    OutputAnalyzer output = new OutputAnalyzer(pb.start());

    output.shouldNotContain("error");

    output.shouldHaveExitValue(0);
  }

  static class ThreePlusMSSystemGC {
    public static void main(String [] args) {
      // From running this test 3 System.gc() were always
      // enough to see the failure but the cause of the failure
      // depends on how objects are allocated in the CMS generation
      // which is non-deterministic.  Use 30 iterations for a more
      // reliable test.
      for (int i = 0; i < 30; i++) {
        System.gc();
      }
    }
  }
}