In the simple example given, there is no particular advantage; however, in many situations it is often useful to interact with the derived class using only the interface contract from which is was derived.
Using constructs of this type are useful when it is not known in advance which of its many potential derived class implementations will be actually be instantiated. This allows generic programming constructs to be applied to a plethora of potential run-time variations.
Can someone please explian more eloborately on this one? Using List list = new ArrayList(), will I be invoking list's methods or the ArrayList methods with the reference variable list
List is an interface where as Arraylist is a class. Arraylist implements all the methods in List... So the arraylist's methods are invoked as the method body is present in Arralist
