[michaelfeathers]

Close, but not quite there. You should leap over tall buildings to make sure that you never have to set y to null.

In my code, I'm only dealing with null if a API gives me one. At that point, I take some sort of action to make absolutely sure I'm not passing it along to anyone else. This means using exceptions, the null object pattern, or Optional without a need to dereference. The goal is to prevent a proliferation of references that could be null and therefore have to be checked.