> Thanks for the clarification. My question is about the error above "error: > class $iwC needs to be abstract" >
This is a fairly confusing scala REPL (interpreter) error. Under the covers, to run the line you entered into the interpreter, scala is creating an object called $iwC with your code inserted into it. So this error is telling you that you cannot create a val in an object (or in a line of the REPL) without giving it a value. and what does the RDD brings, since I can do the DSL without the "people: people: > org.apache.spark.rdd.RDD[Person]" > This is just assigning the type for the variable people (which is really only there for people reading the code in this particular example). In the case of the line from the first example where we leave it out, the scala compiler will add it for us using type inference<http://docs.scala-lang.org/tutorials/tour/local-type-inference.html> .