What's the main reason to prefer List(interface) over Linkedist etc(implementations)

Question

Suppose we wanna define and use a LinkedList in our code. I would define it this way:

LinkedList<String> list= new LinkedList<>(); 

Why some people use the interface List

List<String> list = new LinkedList<>();

to define a LinkedList? What are the advantages?

Answer 1

If you use following :

List<String> list = new LinkedList<>();

Then everywhere, in your code, you just using List<String> list. It means, that if you want use ArrayList, the only thing you have to do is to change one line : List<String> list = new ArrayList<>(); and it will work perfectly in all other code, no matter how complex it is.

If you are using LinkedList, you can have huge problems with switching to something else.