class FuShuException extends Exception{
private int val;
FuShuException(String mess,int val){
  super(mess);
  this.val = val;
}
public int getVal(){
  return val;
}
}


class Demo｛//Demo这显示错误
  int div(int a ,int b)throws FuShuException{
  if(b<0)
  throw new FuShuException("出现负数",b);
  return a/b;
}
}

public class ExceptionDemo2{
public static void main(String args []){
Demo d  = new Demo();
try{
  int x = d.div(4,-1);//传入数字测试
  System.out.println("x = "+x);
} catch(FuShuException e){
  
  System.out.println("程序出现异常");
  System.out.println(e.toString());
  System.out.println("错误数字："+ e.getVal());
}
  System.out.println("OVER");
}
}

看毕老师视频，写的这个代码，怎么上边Demo类这出现错误。。。求解释。。。

class FuShuException extends Exception{
private int val;
FuShuException(String mess,int val){
  super(mess);
  this.val = val;
}
public int getVal(){
  return val;
}
}


class Demo｛//Demo这显示错误
  int div(int a ,int b)throws FuShuException{
  if(b<0)
  throw new FuShuException("出现负数",b);
  return a/b;
}
}

public class ExceptionDemo2{
public static void main(String args []){
Demo d  = new Demo();
try{
  int x = d.div(4,-1);//传入数字测试
  System.out.println("x = "+x);
} catch(FuShuException e){
  
  System.out.println("程序出现异常");
  System.out.println(e.toString());
  System.out.println("错误数字："+ e.getVal());
}
  System.out.println("OVER");
}
}

看毕老师视频，写的这个代码，怎么上边Demo类这出现错误。。。求解释。。。