Kotlin has introduced many improvements over Java while, at the same time, keeping many of the features that have made Java one of the most popular languages over the past two decades. After reading this chapter, you should feel comfortable with the different types of variables, and understand type inference and the various data types in the Kotlin language. You should also understand the new contracts support added in Kotlin 1.3.
Chapter 3, Object-Oriented Programming in Kotlin, will take you through OOP with Kotlin. Whether or not you have programmed in an OOP language before, you will learn about the key concepts of this software design approach, and how you can write code that is object-oriented, using the new features available in Kotlin to make it more structured and readable.