How to make an Integer instance not nullable [duplicate]

Question

Is there a way to ensure an Integer variable not to be null?

I need to create a list of integer values, so I cannot use int type. I need to work with a List<Integer> but this will allow null values for elements...

Do I need to use some particular implementation of List or is there some way to set Integer not nullable?

Note I need a List, not a Set.

Answer 1

You could override the add method of a List and check whether the element is null.

new LinkedList<Integer>() {
    @Override
    public boolean add(Integer e) {
        if(e == null)
            return false;
        return super.add(e);
    }
};

You may need to add this check to the other insertion Methods like add(int pos, E value) or set(int pos, E value).