code: public static List < String > getNonUniqueCobolNames(
              final List < CobolDataItem > cobolDataItems) {
          List < String > cobolNames = new ArrayList < String >();
          List < String > nonUniqueCobolNames = new ArrayList < String >();
          for (CobolDataItem cobolDataItem : cobolDataItems) {
              getNonUniqueCobolNames(cobolDataItem, cobolNames,
                      nonUniqueCobolNames);
          }
          return nonUniqueCobolNames;
      }
docs: Create a list of COBOL names which are not unique. This is useful when we
  build complex type names from the COBOL names. Complex type names need to
  be unique within a target namespace.
  
  @param cobolDataItems a list of root data items
  @return a list of COBOL names which are not unique