In this second section of the book, you will dive deeper into the Kotlin language and standard library. More specifically, functions and functional programming as an alternative to object-oriented programming will be described. Next, more advanced Kotlin-specific features, such as properties and null safety, will be covered, with information on how these features relate back to Java. The advanced type system available in Kotlin will be discussed, with extensive examples on how safer code can be achieved when such a type system is available to the compiler. Next, one of the most fundamental parts of any system, data classes and collections, will be covered, focusing on how and where these improve on what is available in Java. Finally, all the topics will come together as you learn how to build your real-world application using the Lagom microservice...