Derived class properties not getting serialized in kotlin - kotlin

Question

I am trying to serialize derived object using Gson in Kotlin and on serialization I am getting only parent class attributes Gson is ignoring all derived class attributes.
Here is my code:
fun main(args: Array<String>) {
val somename = Sample(1, "somename")
val car = Car(somename, 4)
val car2 = Car(somename, 4)
val vehicles = object : ArrayList<Vehicle>() {
}
vehicles.add(car)
vehicles.add(car2)
val sampleClassResponse = SampleClassResponse(1, vehicles)
val gson = Gson()
val x = gson.toJson(sampleClassResponse)
println(x)
// System.out.println(car.tyre);
}
// Base class:
public class Vehicle {
int number;
String name;
}
Sub class:
import Sample.Sample;
public class Car extends Vehicle {
int tyre;
public Car(Vehicle sample, int tyre) {
super(sample.number, sample.name);
this.tyre = tyre;
}
}
SampleResponse class
public class SampleClassResponse {
private int status;
private List<Vehicle> vehicles;
public SampleClassResponse(int status, List<Vehicle> vehicles){
this.status = status;
this.vehicles = vehicles;
}
}
So here in the main class when I am serializing SampleClass response I am getting output as(with ignored Tyre values)
{"vehicles":[{"number":1,"name":"somename"},{"number":1,"name":"somename"}],"status":1}
and when same code is written in java I am getting output as:
{"status":1,"vehicles":[{"tyre":4,"number":1,"name":"somename"},{"tyre":4,"number":1,"name":"somename"}]}
Could anyone help me in figuring out what am i doing wrong in this kotlin code.
Note: I have used intellij converter to convert code to Kotlin
Here is the java code
public class MainObject {
public static void main(String[] args) {
Sample somename = new Sample(1, "somename");
Car car = new Car(somename, 4);
Car car2 = new Car(somename, 4);
ArrayList vehicles = new ArrayList<Vehicle>() {
};
vehicles.add(car);
vehicles.add(car2);
SampleClassResponse sampleClassResponse = new
SampleClassResponse(1, vehicles);
Gson gson = new Gson();
String x = gson.toJson(sampleClassResponse);
System.out.println(x);
}
}
Base Class:
public class Vehicle {
int number;
String name;
}
Derived class:
public class Car extends Vehicle {
int tyre;
public Car(Sample sample, int tyre) {
this.number = sample.number;
this.name = sample.name;
this.tyre = tyre;
}
}
SampleResponse class:
public class SampleClassResponse {
int status;
List<Vehicle> vehicles = new ArrayList<>();
public SampleClassResponse(int status, List<Vehicle> vehicles){
this.status = status;
this.vehicles = vehicles;
}
}

Answer 1

your code does not compile and that's why I do not know where the problem is.
my proposition of the code in the kotlin is as follows
fun main(args: Array<String>) {
val vehicle = Vehicle("somename", 1)
val car = Car(vehicle, 4)
val car2 = Car(vehicle, 4)
val vehicles = listOf(car, car2)
val response = SampleClassResponse(1, vehicles)
val json = Gson().toJson(response)
println(json)
}
class SampleClassResponse(val status: Int, val vehicles: List<Vehicle>)
open class Vehicle(var name: String?, var number: Int = 0)
class Car(sample: Vehicle, var tyre: Int) : Vehicle(sample.name, sample.number)
now is what you would like to get
{"status":1,"vehicles":[{"tyre":4,"name":"somename","number":1},{"tyre":4,"name":"somename","number":1}]}