运行Flink作业时出错：

ClassCastException: cannot assign instance of java.util.LinkedHashMap to field org.apache.flink.runtime.jobgraph.JobVertex.results of type java.util.ArrayList in instance of org.apache.flink.runtime.jobgraph.InputOutputFormatVertex

下面是源代码

ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

        ParameterTool params = ParameterTool.fromArgs(args);

        env.getConfig().setGlobalJobParameters(params);

        DataSet<String> text = env.readTextFile(params.get("input"));

        DataSet<String> filtered = text.filter(new FilterFunction<String>()

        {
            public boolean filter(String value)
            {
                return value.startsWith("N");
            }
        });
        DataSet<Tuple2<String, Integer>> tokenized = filtered.map(new Tokenizer());

        DataSet<Tuple2<String, Integer>> counts = tokenized.groupBy(new int[] { 0 }).sum(1);
        if (params.has("output"))
        {
            counts.writeAsText(params.get("output"));

            env.execute("WordCount Example");
        }
    }

    public static final class Tokenizer
            implements MapFunction<String, Tuple2<String, Integer>>
    {
        public Tuple2<String, Integer> map(String value)
        {
            return new Tuple2(value, Integer.valueOf(1));
        }
    }

错误：Error image