Caused by: java.lang.ClassCastException: cannot assign instance of scala.collection.immutable.List$S

使用Spark写的WordCount程序如下：

​
package rdd

import org.apache.spark.{SparkConf, SparkContext}

/**
  * Created by leboop on 2019/3/11.
  */
object WordCount {
  private val hdfsUrl="hdfs://bigdata111:9000"
  private val sparkMaster="spark://bigdata111:7077"
  private val filePath="/input/data.txt"
  private val savePath="hdfs://bigdata111:9000/output/wc"

  def main(args: Array[String]): Unit = {
    val conf=new SparkConf().setAppName("word-count").setMaster(sparkMaster)
    val sc=new SparkContext(conf)
    sc.textFile(hdfsUrl+filePath)
      .flatMap(_.split(" ")).map((_,1)).reduceByKey(_+_).saveAsTextFile(savePath)
    sc.stop()
  }
}

​

在开发工具中直接运行，报如下错误：

Caused by: java.lang.ClassCastException: cannot assign instance of scala.collection.immutable.List$SerializationProxy to field org.apache.spark.rdd.RDD.org$apache$spark$rdd$RDD$$dependencies_ of type scala.collection.Seq in instance of org.apache.spark.rdd.MapPartitionsRDD
    at java.io.ObjectStreamClass$FieldReflector.setObjFieldValues(ObjectStreamClass.java:2133)
    at java.io.ObjectStreamClass.setObjFieldValues(ObjectStreamClass.java:1305)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2251)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2169)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2027)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1535)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2245)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2169)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2027)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1535)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:422)
    at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:75)
    at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:114)
    at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:85)
    at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:53)
    at org.apache.spark.scheduler.Task.run(Task.scala:99)

但是将程序打包到Linux系统（Spark集群）上使用Spark submit运行正常。原因是saveAsTextFile(savePath)