@Override
  protected void sampleProcessStats(boolean prepareOnly) {
    if (prepareOnly || osStatsDisabled() || !osStatisticsProvider.osStatsSupported()) {
      return;
    }
    List<Statistics> statisticsList = getStatisticsManager().getStatsList();
    if (statisticsList == null) {
      return;
    }
    if (stopRequested()) {
      return;
    }
    osStatisticsProvider.readyRefreshOSStats();
    for (Statistics statistics : statisticsList) {
      if (stopRequested()) {
        return;
      }
      StatisticsImpl statisticsImpl = (StatisticsImpl) statistics;
      if (statisticsImpl.usesSystemCalls()) {
        osStatisticsProvider.refresh((LocalStatisticsImpl) statisticsImpl);
      }
    }
  }
Returns the <code>ProcessStats</code> for this Java VM. Note that <code>null</code> will be
returned if operating statistics are disabled.

@since GemFire 3.5
geode-core/src/main/java/org/apache/geode/internal/statistics/GemFireStatSampler.java