继承中的this

public class Parent  {
    //看这里的this指的是什么
    public Parent() {
        this.say();
    }
    
    protected void say() {
        System.out.println("father");
    }
}

public class Sun extends Parent{
    public Sun() {
    }

    @Override
    protected void say() {
        System.out.println("sun");
    }
}

public class TestExtends {
    public static void main(String[] args) {
        Sun sun = new Sun();
    }
}