协变返回类型

协变返回类型:子类方法重写父类方法,但返回类型是相应父类方法 返回值的子类(接口也行)。

class Something {

}

class Bone extends Something{

}

class Animal {

public Something eat() {

System.out.println("eat something");

return new Something();

}

}

class Dog extends Animal {

public Bone eat() {

System.out.println("eat bone");

return new Bone();

}

}

public class CovariantReturn {

public static void main(String[] args) {

Animal m = new Animal();

Dog d = new Dog();

m.eat();

d.eat();

}

}