This typically should not be used outside of Spark. This gets called automatically if you've instantiated a SparkContext before you log anything. The issue in this case is that the REPL directly creates an object that uses `Logging` (it creates its own `HttpServer`) before it ever creates a SparkContext. So as a result, this initialization doesn't happen in time and some log messages are sent before it's initialized resulting in a log4j warning.

I think this deviates from the behavior we expect of applications - notably that it triggers a log message through spark before ever creating a SparkContext. Maybe it would still be good to add a doc here explaining what's going on.