title: Get JavaSparkContext from a SparkSession
body: <p>Im am using a <code>SparkSession</code> to run my spark application because I use a lot of spark-sql features. I would like to use the <code>JavaSparkContext</code>to create an RDD from a list. But via the Session I can only get an <em>ordinary</em> <code>SparkContext</code>. Is there a way to transform the context in this direction? </p>