class A
{
public void fun1(){
System.out.println("1A");
}
public void fun2(){
this.fun1();
}
};
class B extends A
{
public void fun1(){
System.out.println("2B");
}
public void fun3(){
System.out.println("3B");
}
};
public class PolDemo
{
public static void main (String args[]){
A a = new B();
B b = (B)a;
b.fun3();
b.fun2();
}
}
那为什么经过向上转型A a = new B()后可以向下转型,而用A a = new A()直接新建一个A类就不能向下转型了呢?
追答这是语法规定,多说无益
应该不是,因为错误提示是不能转型