1.  Interoperability refers to the ability to use both the Java and Kotlin languages in a single project. We can call Kotlin functions in Java as well as Java methods and variables in Kotlin code. This gives us the advantage of code reusability.
2. When a Kotlin function is called in Java, it is required use a filename as a reference with kt keyword, for example, KotlinToJavakt.functionName()  However, Kotlin makes it possible to assign different names to file and functions by using JVM annotation. JVM annotation allows the programmer to assign new names to files and functions according to the coding convention.