Kotlin vs Java @Overrides

Question

As shown here, https://stackoverflow.com/a/16639438/8949356 , in Java you can override the function of a declared class when it is public

But I want to know how to do this exact same code in Kotlin, I've tried a lot but haven't found anywhere something on this topic. And I could just go and do this in Java but the rest of my code is in Kotlin, plus I just can't stay with this kind of doubt; Kotlin feels like a great tool to me and want to learn it all.

Answer 1

If you want to override method, Use override keyword.

Like this.

override fun addNumber(i : Int) {
  val sum = i+10
}

You must declare method that be overrided with open keyword. If you don't, You can't override it.

open fun addNumber(i : T)

Answer 2

You can override functions and properties with the override keyword . Note though, that in Kotlin, classes are not extensible by default, so you have to declare the parent with open (ie open class MyClass() ) if you want to extend it (Java classes are still extensible unless final ).