@Override
  public void incrMiscInvocations() {
    stochasticSource.incrMiscInvocations();
  }
This function overrides the initSource in the MetricsBalancer, use
MetricsStochasticBalancerSource instead of the MetricsBalancerSource.
hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/MetricsStochasticBalancer.java