private void loadFromNamespace() throws IOException {
    try (Table table = masterServices.getConnection().getTable(TableName.NAMESPACE_TABLE_NAME);
      ResultScanner scanner =
        table.getScanner(TableDescriptorBuilder.NAMESPACE_FAMILY_INFO_BYTES)) {
      for (Result result;;) {
        result = scanner.next();
        if (result == null) {
          break;
        }
        addToCache(result, TableDescriptorBuilder.NAMESPACE_FAMILY_INFO_BYTES,
          TableDescriptorBuilder.NAMESPACE_COL_DESC_BYTES);
      }
    }
  }
This is a helper class used internally to manage the namespace metadata that is stored in the ns
family in meta table.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/TableNamespaceManager.java