I developed a XML RPC server which will be triggered by a servlet code and it will in-turn run a spark-submit application. XML RPC will then wait for spark-submit to complete and send the result back to servlet.

My question is :-
Can I write a XML RPC server inside my spark job, and serve all request directly from my servlet with using standalone XML RPC server ?
What is the correct method to trigger Apache spark for each web service request ?