### Question:
ActionRDD { @Transient public Tuple2 getReduce(Tuple2<Integer, Integer> x, Tuple2<Integer, Integer> y) { Integer a = x._1(); Integer b = x._2(); a += y._1(); b += y._2(); return new Tuple2(a, b); }  void testReduce(); @Transient Tuple2 getReduce(Tuple2<Integer, Integer> x, Tuple2<Integer, Integer> y); void testCollect(); void testCount(); void testFirst(); void testTake(); void testCountByKey(); void testForEach();  }### Answer:
@Test public void testReduce() { JavaRDD<Integer> parallelize = sparkContext.parallelize(Arrays.asList(1, 2, 3, 4), 3); Tuple2<Integer, Integer> reduce = parallelize.mapToPair(x -> new Tuple2<>(x, 1)) .reduce((x, y) -> getReduce(x, y)); System.out.println("数组sum:" + reduce._1 + " 计算次数:" + (reduce._2 - 1)); }