Kotlin vs Java for Android today
Google has treated Android development as Kotlin-first since 2019, and its modern libraries, samples and documentation assume Kotlin. Jetpack Compose, the recommended UI toolkit, is Kotlin-only. Kotlin's null safety, coroutines for asynchronous work and concise syntax remove whole categories of crashes and boilerplate that Java apps carry.
Java still runs a huge number of existing apps, and the two languages interoperate fully, so there is no need for a risky big-bang rewrite. Our Kotlin vs Java comparison covers the differences, but the practical path is simple: write new features in Kotlin, convert Java classes when you touch them anyway, and migrate screens to Compose gradually.
For teams with Java experience, the learning curve is short, since Kotlin runs on the same platform and uses the same Android APIs. Pairing Java developers with experienced Kotlin engineers for a few sprints, and agreeing coding conventions early, makes the switch smooth without slowing delivery.


