2.8. Option, Some, and None: Avoiding nulls

We’ll discuss the standard type hierarchy for Scala in Section 7.4. However, three useful classes to understand now are the Option class and its two subclasses, Some and None.

Most languages have a special keyword or object that’s assigned to reference variables when there’s nothing else for them to refer to. In Java, this is null; in Ruby, it’s nil. In Java, null is a keyword, not an object, and thus it’s illegal to call any methods on it. But this is a confusing choice on the language designer’s part. Why return a keyword when the programmer expects an object?