在多態(tài)中，子類對(duì)象向上提升為父類類型后，對(duì)于數(shù)據(jù)域和靜態(tài)的，編譯和運(yùn)行都是父類的，但是方法卻是編譯看父類有沒(méi)有，沒(méi)有就不通過(guò)編譯，運(yùn)行則是執(zhí)行子類的方法。為什么呢？

public class Test {
    public static void main(String[] args) {
        Parent p = new Child();
        System.out.println(p.name + "\t" + p.address);
        p.sayName();
    }
}

class Parent {
    public String name = "father";
    public static String address = "JiangXi";
    
    public void sayName() {
        System.out.println(name + "\t" + address);
    }
}

class Child extends Parent {
    public String name = "son";
    public static String address = "ZheJiang";
    
    public void sayName() {
        System.out.println(name + "\t" + address);
    }
}

執(zhí)行結(jié)果為

father  JiangXi
son ZheJiang