@Override
  public void handleNotification(StatisticsNotification notification) {
    for (StatisticId statId : notification) {
      StatisticDescriptor descriptor = statId.getStatisticDescriptor();
      String name = descriptor.getName();
      Number value;

      try {
        value = notification.getValue(statId);
      } catch (StatisticNotFoundException e) {
        value = 0;
      }

      log(name, value);
      statsMap.put(name, value);
    }

    refreshStats();
  }
Right now it only refreshes CPU usage in terms of percentage. This method can be used for any
other computation based on Stats in future.
geode-core/src/main/java/org/apache/geode/management/internal/beans/stats/VMStatsMonitor.java