Kotlin is an object-oriented programming (OOP) language with support for higher-order functions. If you don't know what higher-order functions mean, then do not worry, as there is, Chapter 5, Higher-Order Functions and Functional Programming, dedicated to them. If you have been using a functional language prior to Kotlin, then you will find many functional programming constructs supported in Kotlin.
Over time, software complexity has increased, and OOP abstraction has allowed us to model problems we have to solve in terms of objects. You can view each object as a minicomputer on its own—it has a state and can perform actions. An object through its available actions exhibits some sort of behavior; therefore, there is a clear analogy between objects/entities and real life.
The first characteristic of an object-oriented abstraction...
