Worked on modernizing the facebook/react-native Android codebase by migrating property exposure annotations from Java to Kotlin. Focused on converting ReactPropGroup, ReactPropertyHolder, and ReactProp to Kotlin, this effort improved maintainability and type safety for the annotation processing pipeline. The migration unified annotation support across the Android bridge, reducing fragmentation between Java and Kotlin code and enabling safer future contributions. Leveraged skills in Android development, code conversion, and annotation processing, utilizing both Java and Kotlin throughout the process. The work enhanced static analysis capabilities and aligned the codebase with ongoing Kotlin-based modernization efforts, supporting long-term maintainability for React Native Android.