public Admin getAdmin() throws IOException {
    if (hbaseAdmin == null) {
      this.hbaseAdmin = getConnection().getAdmin();
    }
    return hbaseAdmin;
  }
Returns an Admin instance which is shared between HBaseTestingUtility instance users. Closing
it has no effect, it will be closed automatically when the cluster shutdowns
hbase-server/src/test/java/org/apache/hadoop/hbase/HBaseTestingUtil.java