Kotlin

Something that has always been a bit of a limitation in the Java numeric type system is the lack of support for unsigned integers. It is not particularly common to have to work with unsigned types, but when it does happen, it’s usually unpleasant in some way. Libraries like Guava have provided utilities to make it cleaner, and recent updates to Java 8 also included some unsigned helper methods.

Kotlin 1.3 has an experimental feature to make unsigned types a full citizen of the type system, while still having all of the performance of primitive integer types. Let’s take a look!

With Kotlin 1.3, a new experimental feature called “Inline Classes” is now available. This post is a somewhat deep dive into the nature of the implementation, how it works, where the edges are, and what limitations currently exist. Let’s take a look!

Kotlin 1.3 is bringing a new experimental feature to the compiler to help with improving program correctness via the type-system: contracts.

Contracts are a tool that allow library code (both standard library and your libraries) hint to the compiler about the constraints that are ensured on types based on the use of functions in your program. Let’s see how this can be used in practice.

Recently I wrote an article about de-structuring in TypeScript, and hinted that Kotlin has a similar feature, but in more of a “strongly typed” language style.

Kotlin has an annotation called @JvmDefault which, like most of the “Jvm” prefixed annotations, exists to help massage the Kotlin compiler output to match Java classes in a certain way. This annotation was added in 1.2.40, and has now seen some experimental enhancements in 1.2.50, so it seems worth exploring what this is all about.