code: public void createRelationFieldMap(Props props)
     {
        byte[] fieldMapData = null;
        for (Integer key : RELATION_KEYS)
        {
           fieldMapData = props.getByteArray(key);
           if (fieldMapData != null)
           {
              break;
           }
        }
  
        if (fieldMapData == null)
        {
           populateDefaultData(getDefaultRelationData());
        }
        else
        {
           createFieldMap(fieldMapData);
        }
     }
docs: Creates a field map for relations.
  
  @param props props data