title: Retrieve SparkContext from SparkSession
body: <p>I'm running a spark batch job and uses <code>SparkSession</code> as I need a lot of spark-sql features to process in each of my components. 
  The <code>SparkContext</code> is initialized in my parent component and been passed to the child components as <code>SparkSession</code>. </p>
  
  <p>In one of my child components, I wanted to add two more configurations to my <code>SparkContext</code>. Hence, I need to retrieve the <code>SparkContext</code> from the <code>SparkSession</code>, stop it and recreate the <code>SparkSession</code> with the additional configuration. To do so, how can I <strong>retrieve SparkContext from SparkSession</strong>?</p>