Hacker News Reader

If you construct an object once, then what is the difference between that and a singleton?

The answer is scope. Singletons exist explicitly for the purpose of violating scoping for the convenience of not having to thread that dependency through constructors.

https://testing.googleblog.com/2008/08/root-cause-of-singlet...

View on HN

Calling these "singletons" maybe created confusion here, I'm more talking about singleton in the sense of a value that is created once and shared (i.e. injecting a value as a "Singleton" via something like Guice). I'm not arguing that you need to have values in global scope, I'm arguing that parameterless constructors prevent you from using shared values (actually _unless_ you have singletons in global scope).

Reply on news.ycombinator.com