@Override
  public void close() {
    if (pool != null) {
      pool.shutdown();
    }
    admin.close();
  }
A helper to modify or remove HBase granted user default and access HDFS ACLs over hFiles.
hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/SnapshotScannerHDFSAclHelper.java