How do I get an IntStream from a List?

I guess (or at least it is an alternative) this way is more performant:

public static IntStream baz(List<Integer> list)
{
    return list.stream().mapToInt(Integer::intValue);
}

since the function Integer::intValue is fully compatible with ToIntFunction since it takes an Integer and it returns an int. No autoboxing is performed.

I was also looking for an equivalent of Function::identity, i hoped to write an equivalent of your bar method :

public static IntStream qux(List<Integer> list)
{
    return list.stream().mapToInt(IntFunction::identity);
}

but they didn’t provide this identity method. Don’t know why.