java中异常注意的细节2

class A extends Exception{
     A(){
        super();
     }
     A(String msg){
        super(msg);
     }
}
 
class B extends A{
     B(){
        super();
     }
     B(String msg){
        super(msg);
     }
}
 
public class Test{
   public static void main(String[] args){
       try{
          throw new B();
       }catch(A e){
          System.out.println("A");
       }catch(B e){//编译挂了知道不？异常中发生多态时一定要注意要将父类的异常写在下边！
          System.out.println("B");
       }catch(Exception e){
          System.out.println("Exception");
       }
   }
}