To give some credit to Java, it is a robust language that has been around for twenty-two years and has introduced so many new features over these years that can be implemented due to its massiveness.
Java vis-a-vis Kotlin
100% interoperability with Java: Kotlin’s main popularity is the interoperability with Java. You can also have Java and Kotlin code co-exist well in the same project and compile perfectly. And because Kotlin and Java can co-exist so well, you can start using Kotlin without having to convert an entire project or starting afresh. Due to the interoperability and interchangeability, you can also benefit from the huge number of Java libraries and frameworks available in the developers market in your Kotlin projects.
Concise and idiomatic: Kotlin requires way less code to write. For example, in Java to write a POJO class with two variables, you have to declare the variables and then assign Getters/Setters for those variables, whereas in Kotlin all you need is
data class User(var name: String, var age: Int)
It drastically reduces the amount of boilerplate code that programmers need to write. The fewer the code, the better it’s execution.
No cost adoption: Kotlin, being open source project, you can use a high quality, one-click Java-to-Kotlin converter tool converting existing Java projects file at a time and convert big and complex projects with millions of lines of code.
Easy learning curve: Kotlin is approachable and can be acquired in a few hours by simply reading the language reference. It has a clean and intuitive syntax. For Java developers, Kotlin is designed to have a gentle learning path and they will find that most of the Kotlin syntax feels familiar.
Less buggy, safer option: Kotlin makes it possible to avoid entire classes of errors such as NullPointExceptions. It protects you from mistakenly operating on nullable types, including those from Java. If you check a type is right, the compiler will auto-cast it for you.
And last but not the least Kotlin has the top rated support of Android Studio since the development of both (Kotlin and Android Studio) is by JetBrains – the company behind the IntelliJ – the IDE for Android Studio.