code: public SimpleJob setSimpleJoin(String[] masterLabels, String[] masterColumns,
                                     String[] dataColumns, String masterPath) throws DataFormatException {
          String separator = conf.get(SEPARATOR);
          return setSimpleJoin(masterLabels, masterColumns, dataColumns, masterPath, separator, false);
      }
docs: Easily supports the Join. To use the setSimpleJoin,
  you must be a size master data appear in the memory of the task.
  @param masterLabels label of master data
  @param masterColumns master column's
  @param dataColumns data column's
  @param masterPath master data HDFS path
  @return this
  @throws DataFormatException