A brief history
Android was built on Java. For the first decade of the platform's existence, Java was the only real option for native Android development. Millions of applications were written in it, and it served its purpose — but it also came with limitations that became increasingly difficult to ignore as mobile development matured.
In 2017, Google announced that Kotlin would be an officially supported language for Android development. In 2019, it went further — Kotlin became the preferred language for Android. Today, all of Google's own Android development documentation is written in Kotlin first. New Android APIs are designed with Kotlin in mind. The direction has been clear for years.
What Kotlin actually improves
The differences between Kotlin and Java are not superficial. They reflect a fundamentally more modern approach to writing software safely and clearly.
Null safety is the most significant practical improvement. In Java, null pointer exceptions are one of the most common sources of application crashes. Kotlin's type system distinguishes between nullable and non-nullable types at the language level, making an entire class of bugs impossible to introduce without the compiler catching them first. For users, this means more stable applications. For developers, it means less time debugging crashes that should never have happened.
Kotlin's syntax is also significantly more concise than Java. Less boilerplate code means less code to write, less code to read, and less code to maintain. This is not a cosmetic benefit — it has real implications for development speed, code quality, and the ability to reason about what a piece of code is actually doing.
Kotlin does not just make Android development faster — it makes it safer. Fewer crashes, more readable code, and better tools for writing software that behaves predictably.
Coroutines and asynchronous programming
One of the historically difficult aspects of Android development has been managing asynchronous operations — network calls, database queries, and other tasks that run in the background while keeping the user interface responsive. Java's approach to this has always been verbose and error-prone.
Kotlin introduces coroutines — a powerful and elegant solution to asynchronous programming that allows developers to write code that reads sequentially while executing efficiently in the background. This results in cleaner code, fewer threading bugs, and applications that perform better under real-world conditions.
Jetpack Compose and the Kotlin ecosystem
Jetpack Compose — Google's modern toolkit for building Android user interfaces — is written entirely in Kotlin and is designed to be used with Kotlin. It represents the future of Android UI development, and it is simply not accessible to developers working exclusively in Java. The entire direction of Android tooling is tied to Kotlin.
Beyond Compose, the broader Kotlin ecosystem — libraries, tools, documentation, and community resources — is growing rapidly. The investment Google and the wider Android development community have made in Kotlin means that the best tools, the most current examples, and the most relevant learning resources are all Kotlin-first.
What this means for new applications
For anyone starting a new Android application today, the choice is straightforward. Java remains a functional option for maintaining existing codebases, but for new development, Kotlin is not just the better choice — it is the correct one. Building on the current recommended stack means access to the best tooling, the clearest documentation, and the strongest long-term support from both Google and the Android development community.
At Extroid Technology, Kotlin is the only language we use for Android development. It is not a preference — it is a standards decision that reflects where the platform is and where it is going.