Why would we use a null check here?

A call to withAdditionalAnnotations(null) should be resolved to the method withAdditionalAnnotations(List), shouldn't it?

And for any other call that adds a null to any part of the list / array, we don't check for null either. So we must be somehow consistent, i.e. checking for all for each add or require our clients to not pass in null as an annotation.

What do you think?