@jerryshao sure we can rename.

IMHO it's not a good idea to have a SparkConfiguration class with getters and setters.  Mutable configuration systems (like Hadoop's) produce a LOT of hard to diagnose bugs, because methods change the configuration and have unintended side effects.  The Typesafe Config API does not have setters, and this is intentional.

Instead, a more idiomatic Scala way is to have methods to produce a new configuration object with updated keys.  Something like `val newConfig = originalConfig ++ Map("updated.key" -> updatedValue)`.