But there's an important difference: 0 is still a number and can safely be added to other numbers, "" is a string which can safely be concatenated with other st

But there's an important difference: 0 is still a number and can safely be added to other numbers, "" is a string which can safely be concatenated with other strings. Java null, however, does not denote a neutral value, it denotes an absence of value, a hole in the paper where a value should be. In fact, if a type has a neutral element on the conceptual level (like 0 or the empty string or the /dev/null logger), then the null-object pattern is applicable and we can return NullObjects instead of null references, so null references are superfluous. If the type has no conceptual neutral element, however, the null reference doesn't relate to a meaningful entity on the conceptual level, either. (Medusa cars which kill you if you try to read the license plate are an obvious exception)