A modern programming language that makes developers happier.

kotlinlang

<https://jelmini.dev/post/2020-01-02-kotlin-classes-final-by-default/>

I do find it interesting that was a *controversial* design choice. I could see how designs that heavily relied on inheritance could find it tedious

I still stand by what I said on that original thread four years ago: the upside of classes being `open` by far outweighs the rare cases where extending a class will break it.

I find myself very rarely extending classes anyways. Most of my use cases wind up being refactored to use composition or delegates. Even before I was doing that, only a fairly small portion (10-15% on an inheritance-heavy project) were classes that ever got extended anyways

The article was good. Would have been better if it had gone on to show extensibility through delegation. It showed `by` used with an Interface, but an example of then replacing the implementation would have been good. I know it’s simple, if you were going to tell me that.