code: private void addRelationName(Relation rField)
      {
          if (rField != null && !rField.isRelatedViaJoinTable())
          {
              String relationName = getJoinColumnName(rField.getProperty());
              if (rField.getProperty().isAnnotationPresent(PrimaryKeyJoinColumn.class))
              {
                  relationName = this.getIdAttribute().getName();
              }
  
              addToRelationNameCollection(relationName);
          }
      }
docs: Method to add specific relation name for given relational field.
  
  @param rField
  relation object.