kotlin - 10 минутный интеллектуальный оргазм.

[ax_mct]

Lack of polymorphism
http://www.natpryce.com/articles/000815.html

Exactly how happy we’ve been with Kotlin has depended on the design style of the code we’re writing:

For functional programming, Kotlin has occasionally been frustrating, because we cannot use parametric polymorphism to factor out duplicated logic as much as we’d like.

For object-oriented programming, Kotlin’s concise syntax for class definitions and language support for delegation avoids a lot of Java’s boilerplate.