Kotlin ClassesLesson 24Free preview

Kotlin Inheritance

This lesson is part of Kotlin · All levels

Summary

This lesson discusses inheritance in Kotlin to build a hierarchy of parent classes (superclass) and subclasses (subclass). By default, all classes in Kotlin are 'final' (closed). To allow a class to be inherited or a method to be overridden, the programmer must explicitly mark it with the keyword 'open'.

Key points

The inheritance is declared using the colon symbol ':' after the name of the subclass
The parent class must be given an 'open' modifier to be inherited
The method that wants to replace its behavior in the subclass must be given an 'open' modifier in the parent and an 'override' in the child.
The keyword 'super' is used to call a constructor or method belonging to the parent class

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