code: protected void setUserJobConfProps(boolean doEarlyProps) {
      Iterator it = userJobConfProps_.keySet().iterator();
      while (it.hasNext()) {
        String key = (String) it.next();
        String val = (String)userJobConfProps_.get(key);
        boolean earlyName = key.equals("fs.default.name");
        earlyName |= key.equals("stream.shipped.hadoopstreaming");
        if (doEarlyProps == earlyName) {
          msg("xxxJobConf: set(" + key + ", " + val + ") early=" + doEarlyProps);
          jobConf_.set(key, val);
        }
      }
    }
docs: This method sets the user jobconf variable specified
  by user using -jobconf key=value
  @param doEarlyProps