@Override
    public void run() {
      if (LOG.isTraceEnabled()) {
        LOG.trace("Clearing JMX mbean cache.");
      }

      // This is pretty extreme but it's the best way that
      // I could find to get metrics to be removed.
      try {
        if (DefaultMetricsSystem.instance() != null) {
          DefaultMetricsSystem.instance().stop();
          // Sleep some time so that the rest of the hadoop metrics
          // system knows that things are done
          Thread.sleep(500);
          DefaultMetricsSystem.instance().start();
        }
      } catch (Exception exception) {
        LOG.debug("error clearing the jmx it appears the metrics system hasn't been started",
          exception);
      }
    }
Restarts the stopped service.
@see #stop()
hbase-hadoop-compat/src/main/java/org/apache/hadoop/metrics2/impl/JmxCacheBuster.java