interface

[michael ngangom]

What is the difference between the following two?

List l=new ArrayList();

and

ArrayList al=new ArrayList();

??

[gurpeet singh]

michael ngangom wrote:What is the difference between the following two?

List l=new ArrayList();

and

ArrayList al=new ArrayList();

??

in case of List l = new ArrayList(); the reference variable l is of type List which is an interface whereas in ArrayList al = new ArrayList(); al is of type ArrayList which is a class. well that was obvious you could say. it is said that it is a good practice to code in terms of interfaces. why ? suppose you have a method which takes list argument as follows :
method2(List list){} now this method can take any type of List. it can take ArrayList. suppose later you changed your implementation and supplied LinkedList , it will work. this flexibility does not come with the second option .

[michael ngangom]

Thanks! That clears my doubt!!