[bookwormAT]

We are using Kotlin in production for two projects. One is a spring boot backend for an online banking app for a large european bank. The other is an Android app for an NGO that gives out microloans to farmers who would not get a loan from a bank.

I find Kotlin a low-risk alternative to Java. Your code still feels like a normal Java project: You use the same frameworks, you have excellent tool support, you can keep searching for java questions on stackoverflow. Kotlin is fast and fully compatible with your Java code.

We are hiring at the moment, and our offer asks for an experienced Java/Spring developer. We just mention Kotlin at the end of the description.

Kotlin is not the right tool if you "hate" Java. It feels like the language that the Java 8 team would have built if backwards compatibility was not an issue.

Apart from some very useful syntactic sugar, it has

  - no checked exceptions
  - classes and methods are by default final
  - no primitives that need to be (auto)boxed to and from objects
  - no "static" context
  - first class functions
  - named function arguments that can have defaults
  - null safety
  - less broken generics

I like Java as a platform, and I think the language is perfectly fine. But Kotlin offers a cleanup and improvement, at almost no cost.