code: public static String[] getListOfDataDirs(Configuration conf) {
      String[] configFilePath = conf.getStrings("dfs.datadir.confpath");
      String[] dataDirs = null;
      if(configFilePath != null && (configFilePath.length != 0)) {
        try {
          DataDirFileReader reader = new DataDirFileReader(configFilePath[0]);
          dataDirs = reader.getArrayOfCurrentDataDirectories();
          if(dataDirs == null) {
            LOG.warn("File is empty, using dfs.data.dir directories");
          }
        } catch (Exception e) {
          LOG.warn("Could not read file, using directories from dfs.data.dir" +
                                                           " Exception: ", e);
        }
      } else {
        LOG.warn("No dfs.datadir.confpath not defined, now using default " +
                                                                "directories");
      }
      if(dataDirs == null) {
        dataDirs = conf.getStrings("dfs.data.dir");
      }
      return dataDirs;
  
    }
docs: Returns a list of data directories from the file provided by the
  dfs.datadir.confpath. If it cannot get the list of data directories
  then the method will return the default dataDirs from dfs.data.dir.