Question

I am new to Java.
I want to know the difference between:

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

and

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

and

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

Thanks

Answer 1

The first one is only valid since Java 7, and is the equivalent of

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

It’s just less verbose.

Same for the third one, which is equivalent to

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

and thus strictly equivalent to the second one.

You should prefer the first one, for the reasons mentioned in the answers to the following question: List versus ArrayList as reference type?