@Sandesh Puligundla​ , Hm hard to tell, but I am pretty sure it is because of the objects you wrote.

Keep in mind that spark is distributed.

You might wanna check out these links:

https://www.placeiq.com/2017/11/how-to-solve-non-serializable-errors-when-instantiating-objects-in-s...

https://stackoverflow.com/questions/40596871/how-spark-handles-object

Not an actual answer to your question, sorry. But this error is hard to pinpoint (for me anyway, hopefully some good coders can solve this).