private String name="FATHER";
public Father(){
whoAmI();
tellName(name);
}
public void whoAmI(){
System.out.println("Father says, I am " + name);
}
public void tellName(String name){
System.out.println("Father's name is " + name);
}
}
class Son extends Father{
private String name="SON";
public Son(){
whoAmI();
tellName(name);
}
public void whoAmI(){
System.out.println("Son says, I am " + name);
}
public void tellName(String name){
System.out.println("Son's name is " + name);
}
}
public class Demo29 {
public static void main (String [] args){
Father f = new Son();
}
}
Son's name is FATHER
Son says, I am SON
Son's name is SON
2.当执行Father()时,它有两条语句,是调用的两个方法,子类重写了父类的这两个方法。由于主函数里Father f = new Son();是典型的父类引用指向子类对象,复合多态性质,所以执行的是重写以后的方法,即子类的方法。
3.这一条最复杂,由于JAVA是动态运行的,只要当执行只才分配值,此时只是Father被new入内存,Son还没有,所以此时的状态是Father.name=FATHER,Son.name=null.其它的都简单了