KotlinClass Inheritance


Any object-oriented programming language has some form of class inheritance. Let me revise:

Imagine you had to program a bunch of fruit: Apples, Oranges and Pears. They all differ in size, shape and color, that's why we have different classes.

But let's say their differences don't matter for a second and you just want a Fruit, no matter which exactly? What return type would getFruit() have?

The answer is class Fruit. We create a new class and make all fruits inherit from it!


  • open {Base Class}
  • class {Derived Class} : {Base Class}({Init Arguments})
  • override {Function Definition}
  • {DC-Object} is {Base Class} == true


Base ClassClass that is inherited from
Derived ClassClass that inherits from Base Class
Init ArgumentsArguments passed to constructor of Base Class
Function DefinitionFunction in Derived Class that has different code than the same in the Base Class
DC-Object”Derived Class-Object“ Object that has the type of the Derived Class