001package subclass.overload;
002
003class A {
004        public void m(String s) { System.out.println("A"); }
005}
006class B extends A {
007        public void m(Object o) { System.out.println("B"); }
008}
009
010class Main {
011        private Main() {}
012        public static void main(String[] args) {
013                String y = "?";
014                Object x = y;
015                B b = new B();
016                A a = b;
017                a.m(y);
018                // a.m(x);
019                b.m(y);
020                b.m(x);
021        }
022}