多态的用法①

package new_doutai;class A{public void f(){System.out.printf("AAAA\n");}}class B extends A{public void f(){System.out.printf("BBBB\n");}}public class duotai {public static void G(A aa){aa.f();}public static void main(String[] args){A aa = new A();B bb = new B();G(aa);G(bb);}}