And then you may implement your function. That's not a problem, we just mark this receiver as nullable. Indeed, in Kotlin, you can define functions on a nullable receiver, like extension functions.

Here we have a nullable string, and we want to call this function on a nullable string. And the most interesting thing here is that the receiver might be nullable. The task here is to implement an extension function IsEmpyOrNull. We'll discuss: basic syntax, nullability, functional programming with Kotlin, object-oriented programming with Kotlin, the power of the Kotlin standard library, and Java interoperability. Note that this course won't cover the programming fundamentals. The course is based on your Java experience it shows the similarities between the two languages and focuses on what's going to be different. We'll have a basic overview of the language, as well as a discussion of many corner cases, especially concerning Java interoperability. This course aims to share with you the power and the beauty of Kotlin. Kotlin code might be compiled not only to JVM bytecode but to JavaScript and Native code as well, but this course is focused on Kotlin/JVM. It’s a pragmatic language with a very low learning curve, and can be quickly grasped by Java developers. Kotlin is 100% compatible with all existing Java frameworks, and has good tooling support. It can be used almost everywhere Java is used today: for server-side development, Android apps, and much more. Kotlin is concise, safe, pragmatic, and focused on interoperability with Java code. The Kotlin programming language is a modern language that gives you more power for your everyday tasks.

Kotlin check for null