Obtains the akka.actor.ActorSystem associated with the active org.apache.spark.SparkEnv.
Default configuration for org.apache.spark.SparkContext.
Obtains the active org.apache.spark.SparkContext object.
Ensures that the currently running org.apache.spark.SparkContext uses the provided configuration.
Ensures that the currently running org.apache.spark.SparkContext uses the provided configuration.
If the configurations are different or force is true
Spark context is stopped and started again
with the given configuration.