Q:

array and object declaration

I'm trying to create an array list of objects. I am a student and my professor requires that all declaration are before the executable code and that all instantiations or initializations (not sure which term) are done in the executable code. I'm new to the List or ArrayList concept and i can't quite figure out how to get this started.
List <Room> roomAry;    //declare array object for rooms

//initialize room array
roomAry = new List<Room>();

This keeps telling me it can't compile.
The error follows:

List is abstract; cannot be instantiated      roomAry = new List
  ();

A:

Because it should be roomAry = new ArrayList<Room> (). It's correct for both .NET and JAVA.
List is just an interface (JAVA)

