code: public SimpleJob setSummarizer(Class<? extends Reducer<Key, Value, Key, Value>> clazz,
                                     boolean combine) {
          return setSummarizer(clazz, combine, DEFAULT_COMBAIN_CACHE);
      }
docs: Job {@link Summarizer} class setting.
  @param clazz {@link Summarizer} class
  @param combine If true is set the combiner in the Summarizer
  @return this