Kotlin - Access Modifiers

Access Modifiers tells the scope of classes,objects,properties Kotlin supports public, private, protected, internal access modifiers.

By default access modifier is public

Example

open class Parent() {
    var a = 1                 // public by default
    private var b = 2         // private to Parent class
    protected open val c = 3  // visible to the Parent and the Derived class
    internal val d = 4        // visible inside the same module

    protected fun e() { }     // visible to the Parent and the Derived class
}

class Derived: Parent() {

    // a, c, d, and e() of the Parent class are visible
    // b is not visible

    override val c = 9        // c is protected
}

fun main(args: Array) {
    val base = Parent()

    // base.a and base.d are visible
    // base.b, base.c and base.e() are not visible

    val derived = Derived()
    // derived.c is not visible
}

private modifier for Constructor

class Parent(val a: Int) {
    // code
}
    

This is default constructor, if we want to it private then we need to use contructor key word

class Parent private constructor(val a: Int) {
    // code
}