docs: private List getColumns(List fields)
      {
          ArrayList columns = new ArrayList();
  
          for (Iterator it = fields.iterator(); it.hasNext();)
          {
              FieldDescriptorDef fieldDef = (FieldDescriptorDef)it.next();
  
              columns.add(fieldDef.getProperty(PropertyHelper.OJB_PROPERTY_COLUMN));
          }
          return columns;
      }