以下程序,请说一下他们的调用关系是怎么样的,以及为什么会输出右边的字符,他们的调用逻辑是怎么样的?


public class Test1 {
     static class A{
        public String run(D obj) {
            return ("A & D");
        }


        public String run(A obj){
            return ("A & A");
        }
    }

     static class B extends A{
        public String run(B obj) {
            return ("B & B");
        }

        public String run(A obj){
            return ("B & A");
        }
    }
        static class C extends B {}
        static class D extends B {}

    static class E{
        public static void main(String[] args) {

            A aa = new A();
            A ab = new B();
            B b = new B();
            C c = new C();
            D d = new D();
            System.out.println(aa.run(b)); //1, A & A    
            System.out.println(aa.run(c)); //2, A & A
            System.out.println(aa.run(d)); //3, A & D

            System.out.println(ab.run(b)); //4, B & A
            System.out.println(ab.run(c)); //5, B & A
            System.out.println(ab.run(d)); //6, A & D

            System.out.println(b.run(b)); //7, B & B
            System.out.println(b.run(c)); //8, B & B
            System.out.println(b.run(d)); //9, A & D
        }

    }
}

java的override方法重写不关注左侧类型,只关注new的类型,调用的是new类型中的方法,也就是从子类方法开始向上寻找,参数类型同理