code: private String getJoinColumnName(Field relation)
      {
          String columnName = null;
          JoinColumn ann = relation.getAnnotation(JoinColumn.class);
          if (ann != null)
          {
              columnName = ann.name();
  
          }
          return StringUtils.isBlank(columnName) ? relation.getName() : columnName;
      }
docs: Gets the relation field name.
  
  @param relation
  the relation
  @return the relation field name