The Kotlin Standard library provides numerous functions that make working with Kotlin much more idiomatic and enjoyable. These include functions and extension functions for working with strings, collections, and other common JDK classes. The Standard library also includes several functions such as let and apply, which really encapsulate what people often think of when they consider idiomatic Kotlin.
In Chapter 12, Fully Functional – Embracing Functional Programming, you'll discover more about Kotlin's rich Standard library of functions and learn about Arrow, a library for fully functional programming with Kotlin.
Let's now move on to understand some improvements to be made and kept in mind before being able to integrate Java with Kotlin.