Initialize List> in Java

Question

How can I initialize List> in Java?

I know List is an interface and I can use ArrayList or Linked

Answer 1

Use

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

or since Java 1.7

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

Answer 2

You can define it as List<List<Integer>> list = new LinkedList();

Answer 3

You can define it as List<List<Integer>> list = new ArrayList<List<Integer>>();.

Then while defining the inner List you can take care of initialising it as ArrayList<Integer>.