Collections.unmodifiableList and defensive copy

Question

If I write

List a1 = Arrays.asList(1, 2, 3);
List a2 = Collections.unmodifiableList(a1);

a2 is r

Answer 1

The idea is that you can't modify the list via a2.

Modifying the a1 list will indeed modify what you see in a2 - this is intended.

Just dont have a public way to access the list a1, and you should have what you want :)