!7

import javax.management.*;
import javax.management.openmbean.CompositeData;
import com.sun.management.GcInfo;
import com.sun.management.GarbageCollectionNotificationInfo;

sclass GCPause {
  long start, duration;
  S name, cause, action;
  
  toString {
    ret "GCPause duration=" + duration + " ms, start=" + start + " (VM time). " + renderStructs(+name, +cause, +action);
  }
}

static L<GCPause> pauses = synchroList();

p {
  onGCNotification(voidfunc(GarbageCollectionNotificationInfo info) {
    GcInfo gcInfo = info.getGcInfo();
    GCPause pause = nu(GCPause,
      start := gcInfo.getStartTime(),
      duration := gcInfo.getDuration(),
      name := info.getGcName(),
      cause := info.getGcCause(),
      action := info.getGcAction());
    pauses.add(pause);
    print("Have GC pause: " + pause);
  });
  showButtons("Make some garbage", f makeSomeGarbage);
}

Began life as a copy of #1013395