I would like to share a project I developed: an internal fitness tracking app created using Java and Kotlin. This app monitors users' fitness activities, including steps taken, calories burned, and distance covered.

Throughout this project, I encountered several challenges:

1. **Interoperability**: Ensuring seamless interoperability between Java and Kotlin was a significant hurdle. I addressed this through careful integration and thorough testing.
2. **Legacy Code Migration**: Gradually migrating existing Java code to Kotlin without disrupting the app was quite challenging. I adopted a step-by-step approach and conducted extensive testing.
3. **Performance Optimization**: Ensuring the app performed well, especially with Kotlin, was demanding. I optimized the code and utilized resources efficiently to tackle this issue.
4. **Code Quality**: Maintaining high code quality and consistency between Java and Kotlin was essential. I achieved this through regular code reviews and adherence to best practices.
5. **Real-Time Data Synchronization**: Integrating wearable devices and managing real-time data synchronization proved to be tricky. I leveraged the Android Wearable API for effective communication.

Through persistence and careful planning, I overcame these challenges, resulting in a more robust and efficient app.