Why does List in Kotlin not have add and remove methods, and Map does not have put?

Hi everyone! I just started learning Kotlin, coming from Java, and encountered a confusing situation. In Java, we are used to working with ArrayList, HashMap and freely calling list.add(), map.put(), etc. But in Kotlin, when I write: ```kotlin val myList = listOf(1, 2, 3) myList.add(4) // Error: Unresolved reference: add val myMap = mapOf("a" to 1, "b" to 2) myMap.put("c", 3) // Error: Unresolved reference: put ``` The compiler complains that such methods don't exist. I tried using mutableListOf and mutableMapOf — there add and put work. But why don't regular listOf and mapOf have them? Is this a language bug? Or am I misunderstanding Kotlin's philosophy? Please tell me how to properly work with collections in Kotlin when I need to both add elements and just read data? And what is the difference between mutable and immutable collections in Kotlin?