There’s a strand of thinking which holds that null references are a common source of avoidable errors that the compiler could have prevented in a better-designe

There’s a strand of thinking which holds that null references are a common source of avoidable errors that the compiler could have prevented in a better-designed language. The objection is not so much that nulls exist, but that it’s impossible to declare a reference variable as “not null” in a way that the compiler can check. Tony Hoare recently (2009) called null references his “Billion Dollar Mistake” [1, 2, 3]. 1. http://qconlondon.com/london-2009/presentation/Null+References:+The+Billion+Dollar+Mistake http://qconlondon.com/london-2009/presentation/Null+Referenc... 2. http://www.infoq.com/presentations/Null-References-The-Billion-Dollar-Mistake-Tony-Hoare http://www.infoq.com/presentations/Null-References-The-Billi... 3. http://lambda-the-ultimate.org/node/3186 http://lambda-the-ultimate.org/node/3186