package?com.duotai; public?class?cat?implements?Animals{ public?void?eat(){ System.out.println("吃魚"); } public?void?catchMouse()?? ????{?? ????????System.out.println("抓老鼠");?? ????}?? } public??interface?Animals?{ ???????public??void?eat(); } public?void?animalTest(String?className)?throws?ClassNotFoundException,?IllegalAccessException,?InstantiationException?{ ????//利用反射獲得類的對(duì)象 ????Class?animalClass?=?Class.forName(className); ????Animals?animal?=?(Animals)?animalClass.newInstance(); ????animal.eat(); } public?class?demo?{ public?static?void?main(String[]?args)?{ demo?a?=new?demo(); try?{ a.animalTest("cat"); }?catch?(ClassNotFoundException?e)?{ //?TODO?Auto-generated?catch?block e.printStackTrace(); }?catch?(IllegalAccessException?e)?{ //?TODO?Auto-generated?catch?block e.printStackTrace(); }?catch?(InstantiationException?e)?{ //?TODO?Auto-generated?catch?block e.printStackTrace(); } ????????} } 對(duì)于多態(tài)的定義以及使用方法我都可以理解，但是我最不理解的就是多態(tài)到底具有什么用處，我查了網(wǎng)上大部分都是舉例父類animal，，，子類dog，cat ?。。。。animal a=new dog（）;然后調(diào)用方法a.方法，，，，，，，但是我不理解的就是我直接dog a = new dog();調(diào)用方法a.方法不就可以了，多態(tài)的優(yōu)點(diǎn)在哪里呢？在代碼方面我也并沒有看到有優(yōu)化的作用啊。并且與繼承相比較，多態(tài)好像只多了一個(gè)重載的一個(gè)作用？，希望各位指導(dǎo)一下，十分感謝！！