protected String mapKey(String[] keys, int maxkl) {
    if (keys.length < 1) {
      throw new IllegalArgumentException("at least 1 key fragments expected");
    }
    // shortest map key is namespace
    StringBuilder strb = new StringBuilder(namespace);
    for(int k = 0; k < Math.min(maxkl, keys.length - 1); ++k) {
      strb.append('.');
      strb.append(keys[k]);
    }
    return strb.toString();
  }
Compose a property map key from property key fragments.
@param keys the property key fragments
@param maxkl the maximum number of fragments in the map key
@return the property key used by the store
standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/properties/PropertyManager.java