In this section, you’ll learn how to use Java code in a Kotlin file. The code for this article can be downloaded from the GitHub repository.

Other than IntelliJ IDEA, this article does not require any specific installations. Finally, you’ll have a quick look at how to call Kotlin's object class in Java. You’ll also see the replacement of Kotlin filenames and function names using a Kotlin-provided JVM annotation. You’ll then see how to handle the Kotlin reserve words and utilize Kotlin written code in Java with variables, functions, extension functions, and the Kotlin class.

You’ll start by calling Java static variables and functions in Kotlin, then move onto the Java collections, and explore some examples of calling Java classes in Kotlin. Similarly, you can call Kotlin code in Java. Instead, you can use each and every line of Java code in Kotlin and start writing new functionalities here. For example, if you have an existing Java project with classes and functions, then you do not need to rewrite everything in Kotlin from scratch. This gives you the advantage of code reusability. You can call Kotlin functions in Java as well as Java methods and variables in Kotlin code.

Interoperability refers to the ability to use both the Java and Kotlin languages in a single project. Learn about interoperability between Java and Kotlin in this article by Abid Khan, an application developer and test engineer with over 10 years of experience, and Igor Kucherenko, an Android developer at Techery, a software development company that uses Kotlin as the main language for Android development.

Static kotlin