Does Kotlin's MutableList add() function always add to the end of the list?

Question

I am adding an element into a MutableList and I want to know its index.

mutableList.add(foo)

Will the index of the most recently added element always be the last index mutableList.size - 1 like it is with ArrayList?

I don't want to use mutableList.indexOf(foo) because I believe it takes O(n). I'm not finding lot of documentation on these.

Answer 1

Yes, MutableList.add() always adds to the end of the list (this is a requirement for any class implementing the interface). I've filed an issue to say this explicitly in the documentation.