what is the sense of final ArrayList?

Question

Which advantages/disadvantages we can get by making ArrayList (or other Collection) final? I still can add to ArrayList new elements, remove elements and update it. But what

Answer 1

I personally mark the collections field of my classes as final to save the users of my class from checking whether it is null or not. This works because, once the value is already assigned to a final variable, it can never be reassigned to another value, including null.