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kotlinlang

Hi all
Why do I need parentheses at the end of the following inheritance:
```class NoInterestsFound : RuntimeException() ```

They signify that you’re _extending_ a class. If you omit the parentheses, you’re _implementing_ an interface. Since `RuntimeException` is a class, it is being extended and requires the parentheses as it is effectively calling the superclass constructor

Because `RuntimeException` is a class and you have to call its constructor. It's like calling `super()` in the first line of a Java constructor, kotlin just forces you to do it explicitly.

as there are no keywords like `extends` and `implements` in kotlin, I'd say it's also very useful as a differentiation between interfaces and superclasses (as <@UD17D4K8W> said)