Date: 2013aug27 Language: Scala Q. Scala: Scala has many collection classes and it can also use the Java collections. What should I use? A. MUTABLE Use mutable.ArrayList when you want something with order than can change. Use mutable.Set when you want a set you can change. Use mutable.HashMap when you want a hash you can change. These require:

import collection.mutable

You can convert a Java ArrayList into a Scala mutable.ArrayList with asScalaBuffer() IMMUTABLE I don't have preferences for immutable connections yet.