Meta has been on a years-long undertaking to translate our entire Android codebase from Java to Kotlin. Today, despite having one of the largest Android codebases in the world, we’re well past the halfway point and still going. We’re sharing some of the tradeoffs we’ve made to support automating our transition to Kotlin, seemingly simple transformations that are surprisingly tricky, and how we’re collaborating with other companies to capture hundreds more corner cases. Android development at Met...