public static List<File> sortInBatch(File file,Comparator<String> cmp) throws IOException {
  return sortInBatch(file,cmp,DEFAULTMAXTEMPFILES);
}

public static List < File > sortInBatch ( File file , Comparator < String > cmp ) throws IOException { return sortInBatch ( file , cmp , DEFAULTMAXTEMPFILES ) ; }
this will simply load the file by blocks of x rows , then sort them in - memory , and write the result to temporary files that have to be merged later .
