In this year top-5 promising languages list, I put Kotlin in fifth place among the languages that you should definitely check in 2017. This week Google I\O announced that Kotlin is now an officially supported language for Android Development. I like to be right in my forecast. However, I need to be honest. Back then, I didn’t know well why I put it there. I just had some kind of ethereal intuition.

In the article I wrote:

So, why Kotlin? There is no killer feature here. The only thing can push Kotlin as a solid replacement to Java is the company that it is developing it: JetBrains.

Everybody knows JetBrains and most of us love their IDEs. This can be enough to slowly push Kotlin in the wild, especially for Android development (Android Studio is based on JetBrains IDE, after all). It this enough? Probably, not. Will see.

I’m not convinced of this language, but I think we will definitely see if it can be something serious during this year. That’s why I put it here.

In this quote, there are things wrong and things on spot. The greatest mistake is that I was underestimating Kotlin. Some weeks after the article, I started looking deeper into Kotlin and I discovered that it is a real pleasure to work with. Probably, its killer feature is the complete 100% straightforward compatibility with existing Java code. It takes many things from other older attempts in JVM languages and, in my opinion, make them better and more intuitive for Java developers. In conclusion, I am much more convinced in Kotlin than 6 months ago.

However, I think I got something right. The selling point of Kotlin, its most promising feature, is the JetBrains and Android support. Kotlin had a very high chance of becoming the way to go for Android development. I didn’t expect this to be true so soon!

Now that Kotlin is an official language for Android, it is much more important to look at it in 2017! Congratulation to the Kotlin team!