Kotlin is designed to be fully interoperable with Java, allowing developers to use both languages in the same project. Kotlin's modern syntax and features can lead to more concise and readable code compared to Java, reducing boilerplate and improving overall efficiency in development.

Yes, existing Java projects can be migrated to Kotlin. Kotlin provides tools to convert Java code to Kotlin, making the transition smooth. Migrating can help leverage Kotlin’s modern features and enhance the project's code quality and maintainability.

Kotlin is versatile and can be used to develop a wide range of applications, including Android apps, server-side applications, and web applications. Its flexibility and modern features make it suitable for various development needs, from simple apps to complex enterprise solutions.

Kotlin supports modern development practices through its features such as coroutines for asynchronous programming, extension functions for enhancing existing classes, and data classes for simplifying data handling. These features enable efficient and effective development, aligning with current industry best practices.