groupBy(int) is undefined for the type SingleOutputStreamOperator while running streaming example provided on webpage

[Vinaya M S]

Hi,

I'm new to Flink. Can anyone help me with the error below.

Exception in thread "main" java.lang.Error: Unresolved compilation problem:

The method groupBy(int) is undefined for the type
SingleOutputStreamOperator<Tuple2<String,Integer>,capture#1-of ?>


The code snippet is:

DataStream<Tuple2<String, Integer>> dataStream = env

                .socketTextStream("localhost", 9999)

                .flatMap(new Splitter())

                .groupBy(0)

                .sum(1);


Thank you.