What's Kotlin Backing Field For?

Question

As a Java developer, the concept of a backing field is a bit foreign to me. Given:

class Sample {
    var counter = 0 // the initializer value is written directly         


        

Answer 1

My understanding is using field identifier as a reference to the property's value in get or set, when you want to change or use the property's value in get or set.

For example:

class A{
    var a:Int=1
        get(){return field * 2}    // Similiar to Java: public int geta(){return this.a * 2}
        set(value) {field = value + 1}
}

Then:

var t = A()
println(t.a)    // OUTPUT: 2, equal to Java code: println(t.a * 2)
t.a = 2         // The real action is similar to Java code: t.a = t.a +1
println(t.a)    // OUTPUT: 6, equal to Java code: println(t.a * 2)