static Map<byte[], ListMultimap<String, UserPermission>> loadAll(Configuration conf)
    throws IOException {
    Map<byte[], ListMultimap<String, UserPermission>> allPerms =
      new TreeMap<>(Bytes.BYTES_RAWCOMPARATOR);

    // do a full scan of _acl_, filtering on only first table region rows

    Scan scan = new Scan();
    scan.addFamily(ACL_LIST_FAMILY);

    ResultScanner scanner = null;
    // TODO: Pass in a Connection rather than create one each time.
    try (Connection connection = ConnectionFactory.createConnection(conf)) {
      try (Table table = connection.getTable(ACL_TABLE_NAME)) {
        scanner = table.getScanner(scan);
        try {
          for (Result row : scanner) {
            ListMultimap<String, UserPermission> resultPerms =
              parsePermissions(row.getRow(), row, null, null, null, false);
            allPerms.put(row.getRow(), resultPerms);
          }
        } finally {
          if (scanner != null) {
            scanner.close();
          }
        }
      }
    }

    return allPerms;
  }
Load all permissions from the region server holding {@code _acl_}, primarily intended for
testing purposes.
hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/PermissionStorage.java