How to turn a Mutable Collection into an Immutable one

Question

I was writing a small piece of code in which I internally handle my data in a mutable map, which in turn has mutable lists.

I wanted to expose my data to the API use

Answer 1

Use Collections to converts a Mutable list to Immutable list, Example:

Mutable list:

val mutableList = mutableListOf()

Converts to Immutable list:

val immutableList = Collections.unmodifiableList(mutableList)