In Java, the final modifier is required to make a local-variable non-assignable.

If you check that an object is instanceOf some class, then inside that if block, the variable will be treated as such, without you having to downcast it manually. Kotlin also does not require a cast operator. Java 10 has that too, but with Kotlin's stronger type system it's even more valuable. All of these can be extension methods now!įor all local variables, you just use var and the compiler will figure out the type on its own.

This also marks the death of the dreaded StringUtils class full of static methods. If you stick to Kotlin methodology, your programs are unable to throw the dreaded NullPointerExceptions at you.ĭid you ever want a null-safe variant of myStringVariable.isNullOrEmpty() in Java? Well, Kotlin has you covered! You can write static methods (with certain signatures) and call them as if they were regular member methods. String (non- null String) and String? (nullable String) are two distinct types in Kotlin. Less clutter in code, and my wrist is really happy about this.

Not 'optional' as in 'well most of the time it works without them, just sometimes it makes a difference' but as in 'use them or drop them, the program won't change'. I could fill entire books about the things I like about Kotlin. Kotlin is very interesting from a language perspective, it has many merits, but also some pitfalls and awkward design choices. Kotlin is a JVM-based language developed by Jetbrains, known for their IDEs and developer tools. I've seen my fair share of Kotlin and also used it in production. This is an article I've wanted to write for quite some time now.

Any kotlin