code: Path[] getLocalFiles(JobConf conf, String subdir) throws IOException{
      String[] localDirs = getLocalDirsFromConf(conf);
      Path[] paths = new Path[localDirs.length];
      FileSystem localFs = FileSystem.getLocal(conf);
      for (int i = 0; i < localDirs.length; i++) {
        paths[i] = new Path(localDirs[i], subdir);
        paths[i] = paths[i].makeQualified(localFs);
      }
      return paths;
    }
docs: get the full paths of the directory in all the local disks.