2.9 KiB
2.9 KiB
Use Kotlin
Context and Problem Statement
Android applications can be written in Java, Kotlin, or a mix of the two. What should the project choose?
Considered Options
- Use Kotlin for all new code, migrate existing code
- Allow new code to be Kotlin or Java
- Use Java for all new code, migrate existing code
Decision Outcome
Chosen option: "Use Kotlin for all new code, migrate existing code", because comes out best (see below).
Consequences
- Good, because it simplifies the number of languages contributors need to know
- Good, because Kotlin has features that mitigate issues that require third party libraries in Java (null pointer exceptions, immutable collections, etc)
- Good, because Kotlin's support for structured concurrency resolves an entire class of bugs
- Good, because Android ecosystem, especially Google libraries, is increasingly moving to Kotlin. Google describes Kotlin as part of Modern Android Development
- Bad, because contributing to third party libraries used by the app may still require Java
- Bad, because Kotlin may be unfamiliar to potential contributors
- Neutral, because tools exist to automatically convert Java to equivalent (but possibly not idiomatic) Kotlin
Pros and Cons of the Options
Use Kotlin for all new code, migrate existing code
- Good, because the number of languages contributors need to know remains low
- Good, because Kotlin has features that mitigate issues that require third party libraries in Java (null pointer exceptions, immutable collections, etc)
- Good, because Kotlin's support for structured concurrency resolves an entire class of bugs
- Good, because Android ecosystem, especially Google libraries, is increasingly moving to Kotlin. Google describes Kotlin as part of Modern Android Development
- Bad, because contributing to third party libraries used by the app may still require Java
- Bad, because Kotlin may be unfamiliar to potential contributors
- Neutral, because tools exist to automatically convert Java to equivalent (but possibly not idiomatic) Kotlin
Allow new code to be Kotlin or Java
- Good, because it may be easier to attract new contributors already familiar with Java
- Bad, because a single PR may need to modify code in both languages, so contributors likely still need to be familiar with both
- Bad, because anyone conducting PR reviews must be familiar with both languages
- Bad, because although Java and Kotlin can interop it requires additional annotations and sometimes code on the Kotlin side, making the code more complicated
Use Java for all new code, migrate existing code
- Bad, because this is the opposite direction the Android ecosystem is moving in
- Bad, because Kotlin brings significant improvements to Java that would be thrown out
- Bad, because additional work