Changes

//map to only words

JavaRDD<String> wordsRDD = removeBlankLineRDD.flatMap(sentence -> Arrays.asList(sentence.split(" ")).iterator());

JavaPairRDD<String, Long> pairRDD = wordsRDD.mapToPair(word -> new Tuple2<>(word, 1L));

//get frequency

//make frequency as the key

JavaPairRDD<Long, String> reversedMap = totals.mapToPair(t -> new Tuple2(t._2, t._1));

List<Tuple2<Long, String>> results = reversedMap.sortByKey(false).collect();

results.forEach(t->System.out.println(t));

//close