Spark job is failed due to java.io.NotSerializableException: org.apache.spark.SparkContext

Question

I am facing above exception when I am trying to apply a method(ComputeDwt) on RDD[(Int,ArrayBuffer[(Int,Double)])] input. I am even using extends Serialization option to serialize objects in spark.Here is the code snippet.

input:series:RDD[(Int,ArrayBuffer[(Int,Double)])] 
DWTsample extends Serialization is a class having computeDwt function.
sc: sparkContext

val  kk:RDD[(Int,List[Double])]=series.map(t=>(t._1,new DWTsample().computeDwt(sc,t._2)))

Error:
org.apache.spark.SparkException: Job failed: java.io.NotSerializableException: org.apache.spark.SparkContext
org.apache.spark.SparkException: Job failed: java.io.NotSerializableException: org.apache.spark.SparkContext
at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:760)
at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:758)
at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:60)
at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
at org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:758)
at org.apache.spark.scheduler.DAGScheduler.org$apache$spark$scheduler$DAGScheduler$$submitMissingTasks(DAGScheduler.scala:556)
at org.apache.spark.scheduler.DAGScheduler.org$apache$spark$scheduler$DAGScheduler$$submitStage(DAGScheduler.scala:503)
at org.apache.spark.scheduler.DAGScheduler.processEvent(DAGScheduler.scala:361)
at org.apache.spark.scheduler.DAGScheduler.org$apache$spark$scheduler$DAGScheduler$$run(DAGScheduler.scala:441)
at org.apache.spark.scheduler.DAGScheduler$$anon$1.run(DAGScheduler.scala:149)

Could anyone suggest me what could be the problem and what should be done to overcome this issue?

Answer 1

The line

series.map(t=>(t._1,new DWTsample().computeDwt(sc,t._2)))

references the SparkContext (sc) but SparkContext isn't serializable. SparkContext is designed to expose operations that are run on the driver; it can't be referenced/used by code that's run on workers.

You'll have to re-structure your code so that sc isn't referenced in your map function closure.