(单选) 以下 Spark filter 算子输出结果为()

 public static void filter(){
        //创建SparkConf
        SparkConf conf = new SparkConf().setAppName("map").setMaster("local");
        //创建javaSparkContext
        JavaSparkContext sc = new JavaSparkContext(conf);

        //插入数据
        List<Tuple2<Integer, String>> list = new ArrayList<Tuple2<Integer, String>>();
        list.add(new Tuple2<Integer, String>(1,"a"));
        list.add(new Tuple2<Integer, String>(2,"b"));
        list.add(new Tuple2<Integer, String>(3,"C"));
        list.add(new Tuple2<Integer, String>(4,"d"));
        list.add(new Tuple2<Integer, String>(2,"e"));
        list.add(new Tuple2<Integer, String>(3,"f"));
        list.add(new Tuple2<Integer, String>(2,"g"));

        JavaPairRDD<Integer, String> pair = sc.parallelizePairs(list);

        //filter筛选
        JavaPairRDD<Integer, String> filter = pair.filter(new Function<Tuple2<Integer, String>, Boolean>() {
            public Boolean call(Tuple2<Integer, String> t) throws Exception {
                return t._1%2==0;
            }
        });
        System.out.println(filter.collect());
    }