Question

If I had the following declaration of the list:

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

and

List< HashSet < Integer>> c = new ArrayList< HashSet< Integer>>();

I was wondering how would I be able to add b to c?

I’ve tried c.add(b);
but this doesn’t work.

Thanks for any help!

Answer 1

You cant add a HashSet of integers to a list of integers. They’re two different datatypes. If you would have a HashSet of integers instead of a List of integers, then you would be able to add them to your list.

like this:

HashSet< Integer> b = new HashSet< Integer>();
List< HashSet < Integer>> c = new ArrayList< HashSet< Integer>>();
c.add(b);