Exception in thread "main" org.apache.spark.SparkException: Task not serializable

spark context serializable에 관한 글

https://stackoverflow.com/questions/38807066/unable-to-serialize-sparkcontext-in-foreachrdd

*객체 직렬화를 위해 object에 따로 변수 두기

https://stackoverflow.com/questions/31664819/spark-how-to-use-sparkcontext-within-classes?rq=1

RDD는 drive에서만!

https://stackoverflow.com/questions/31448069/sparkcontext-not-serializable-inside-a-companion-object