Can inheritance be replaced completely by composition?

Question

This question is NOT question like \"inheritence vs composition\".

I understand completely how inheritance differs from composition, I know the Lisk

Answer 1

I think the real question here is inheritance vs. polymorphism. In popular languages like Java the two are combined, i.e. subtype polymorphism is only achieved through implementation inheritance. Go proves that polymorphism can be achieved without inheritance, even in a statically-typed language (and this was known before Go). So the question is, if you can have polymorphism without inheritance, why would you want it with inheritance?

The modern answer seems to be... you wouldn't. Conflating inheritance with polymorphism assumes inheritance is the most common use case. Even James Gosling admits that implementation inheritance was a mistake. That isn't to say it's useless; but the use cases for inheritance could be covered by a framework or DSL rather than forced into every subtype relationship. In this regard, Go had the opportunity to learn from Java's mistake.