@Override
  public boolean clearNamedQueue() {
    if (!isBalancerRejectionRecording) {
      return false;
    }
    LOG.debug("Received request to clean up balancer rejection queue.");
    balancerRejectionQueue.clear();
    return true;
  }
In-memory Queue service provider for Balancer Rejection events
hbase-server/src/main/java/org/apache/hadoop/hbase/namequeues/impl/BalancerRejectionQueueService.java