How to convert a java.util.List to a Scala list

You can simply convert the List using Scala's JavaConverters:

import scala.collection.JavaConverters._

def findAllQuestion():List[Question] = {
  questionDao.getAllQuestions().asScala.toList
}

import scala.collection.JavaConversions._

will do implicit conversion for you; e.g.:

var list = new java.util.ArrayList[Int](1,2,3)
list.foreach{println}