flink基于集合的Source代码运行的时候报错

        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setRuntimeMode(RuntimeExecutionMode.AUTOMATIC);

        //2.source
        // * 1.env.fromElements(可变参数);
        DataStream<String> ds1 = env.fromElements("hadoop", "spark", "flink");
        // * 2.env.fromColletion(各种集合);
        DataStream<String> ds2 = env.fromCollection(Arrays.asList("hadoop", "spark", "flink"));
        // * 3.env.generateSequence(开始,结束);
        DataStream<Long> ds3 = env.generateSequence(1, 10);
        //* 4.env.fromSequence(开始,结束);
        DataStream<Long> ds4 = env.fromSequence(1, 10);

        //3.Transformation

        //4.sink
        ds1.print();
        ds2.print();
        ds3.print();
        ds4.print();

        //5.execute
        env.execute();

刚开始学习，照着网上的代码运行，现在报错，请大神协助