From simple comments that live alongside the code to complex websites like the Android Developer documentation that cover things like platform APIs, build tools, samples, etc., it’s all documentation. They often utilize method chaining to reduce the lines of code as much as possible.Good documentation can make a developer prefer one library over others.ĭocumentation comes in many forms. Builderīuilders provide a simpler way to construct complex objects. This simple delegate makes any lazy initialization thread-safe and easy to read at the same time.

the lambda passed to lazy is only executed once, even in concurrent contexts.service is lazily instantiated upon its first access.The lazy property delegate (if you don't know about them, read: Delegated properties) ensures two things for us: So instead of this Java code: void log(String message) Īnd that's it. While function overloading is still possible in Kotlin, it can be considered a code smell because it's way easier to define functions with parameter default values. Most of you already know this, but it is an especially cumbersome Java pattern that Kotlin solved brilliantly, so I quickly want to gloss over it. Overloading methods/cascading constructors The patterns will start simple but become more complex further in the article so make sure you check out all the sections. However, even if you write Kotlin daily, there still might be some things you did not yet know.

I assume you understand basic Kotlin syntax and basic principles like nullable types. Note that this article is aimed at beginners with little Kotlin experience. Stay tuned, read along, and find out why Kotlin is not just less, more concise, and idiomatic code, but also more fun to write :) After the Kotlin 2021 Premier Online Event taking place just recently and the book 'Java to Kotlin: A Refactoring Guidebook' by Duncan McGregor and Nat Pryce coming out, I thought it was a good time to write about Java patterns and how Kotlin can help you implement them or can even make them obsolete!įor all the Java gurus asking themselves: 'why even bother with Kotlin when I have Java?' Switching from Java to Kotlin is not just a different syntax and null-safety (which by itself would be the killer argument to switch) but also a different kind of programming.

Any type in kotlin