11.1 What is Kotlin?
Named after an island located in the Baltic Sea, Kotlin is a programming language created by JetBrains and follows Java in the tradition of naming programming languages after islands. Kotlin code is intended to be easier to understand and write and also safer than many other programming languages. The language, compiler and related tools are all open source and available for free under the Apache 2 license.
The primary goals of the Kotlin language are to make code both concise and safe. Code is generally considered concise when it can be easily read and understood. Conciseness also plays a role when writing code, allowing code to be written more quickly and with greater efficiency. In terms of safety, Kotlin includes a number of features that improve the chances that potential problems will be identified when the code is being written instead of causing runtime crashes.
A third objective in the design and implementation of Kotlin involves interoperability...