publicclassTset04{publicstaticvoidmain(String[] args){//这段由程序员A编写AnimalTest at =newAnimalTest();
at.test(newCat());
at.test(newBird());}}classAnimalTest{//这段由程序员B编写,//不知道传参传过来个啥。publicvoidtest(Animal a){if(a instanceofCat){Cat c =(Cat)a;
c.catchNouse();}elseif(a instanceofBird){Bird b =(Bird)a;
b.sing();}}}