Covariant Return Type in Java

Overview

Before Java 5 It was restricted to return a subtype from an overridden method of the child class. for example- In the below code getVehicle() method from Vehicle class is returning Car but in its child class SportsVehicle we are returning SportsCar which is a subtype of Car. Covariant Return type allows the more specific return type from the child class.

Example

class Car{
	public String toString(){
		return "Toyota";
	}
}

class SportsCar extends Car{
  
	public String toString() {
		return "Porsche";
	}
}


class Vehicle{
	Car getVehicle() {
		return new Car();
	}
} 

class SportsVehicle extends Vehicle{
	
	@Override
	SportsCar getVehicle() {
		return new SportsCar();
	}
} 

public class CovariantReturnType {
	
	public static void main(String[] args) {
		Vehicle v = new Vehicle();
		Car car = v.getVehicle();
		System.out.println(car);
		v = new SportsVehicle();
		car = v.getVehicle();
		System.out.println(car);
	}

}

Output:

Toyota
Porsche