kotlin-for-java-developers | Solutions for the Kotlin for Java Developers | Machine Learning library

The printMe() method has two receivers: the dispatch receiver and the extension receiver. The dispatch receiver is the instance of the class in which the extension is declared, and the extension receiver is the instance of the receiver type of the extension method. You are accessing contaiverVal in the context of a Container instance (dispatch receiver), not a Data instance (extension receiver).

If you try to do the opposite and access a private property of the Data class inside the printMe(), you will get a compiler error.

when you define an extension function as a member of a class, it is only usable in the context that class. You can access it inside the class or using a scope function where the context object is available as a lambda receiver (this). Those functions are run, with and apply.