code: public static void addNamedOutput(JobConf conf, String namedOutput,
                                  Class<? extends OutputFormat> outputFormatClass,
                                  Class<?> keyClass, Class<?> valueClass) {
      addNamedOutput(conf, namedOutput, false, outputFormatClass, keyClass,
        valueClass);
    }
docs: Adds a named output for the job.
  <p/>
  
  @param conf              job conf to add the named output
  @param namedOutput       named output name, it has to be a word, letters
  and numbers only, cannot be the word 'part' as
  that is reserved for the
  default output.
  @param outputFormatClass OutputFormat class.
  @param keyClass          key class
  @param valueClass        value class