//定義一個(gè)Animal類，Cat類繼承Animal。 public?class?Animal?{ String?str; public?void?voice(){ System.out.println("普通動(dòng)物的叫聲！"); } } class?Cat?extends?Animal{ public?void?voice(){ System.out.println("喵喵喵"); } public?void?catchMouse(){ System.out.println("抓老鼠"); } }public?class?Test?{ public?static?void?testAnimalVoice(Animal?a){ a.voice(); } public?static?void?main(String[]?args){ Animal?a?=?new?Cat(); testAnimalVoice(a); } }Animal?a?=?new?Cat();相當(dāng)于Cat?c?=?new?Cat();? Animal?a?=?c;按我的理解：加載Cat類，建立局部變量c用于存放地址，然后新建了一個(gè)以Cat為模版的對(duì)象，把這個(gè)對(duì)象的地址賦給c；加載Animal類，建局部變量a，把c的值賦給a。我的問(wèn)題：把c的值賦給a的過(guò)程中為何需要繼承，假如Cat類沒(méi)有繼承Animal類，Animal a = c照樣是局部變量的值傳遞啊，為何賦不了值？？？！?。?