public void map() { JavaRDD<Integer> rdd = sc.parallelize(Arrays.asList(1, 2, 3, 4, 5)); JavaDoubleRDD doubles = rdd.mapToDouble(x -> 1.0 * x).cache(); doubles.collect(); JavaPairRDD<Integer, Integer> pairs = rdd.mapToPair(x -> new Tuple2<>(x, x)) .cache(); pairs.collect(); JavaRDD<String> strings = rdd.map(Object::toString).cache(); strings.collect(); }