自己写的异常类的问题？谢谢！！

Question

是对继承类的认识错误：）正确的代码如下：
package execptiondl;
import execptiondl.dlexception;
public class Ninetyeight  //throws dlexecption
{
    public Ninetyeight(  )
    {
       int i = 0;
String DiavArray[] = {"A","B","C","D"};
System.out.println("Hello World!");
try{
while(i<5)
{
System.out.println(DiavArray[i]);
       i++;
}
  }//try
//catch(ArrayIndexOutOfBoundsException e)
catch(dlexception e){
System.out.println(e.toString( ));}    }
public static void main(String[] args) //throws Exception
{
 Ninetyeight d = new Ninetyeight();
}
}package execptiondl;
import java.lang.Throwable.*;
public class  dlexception extends ArrayIndexOutOfBoundsException
{public String toStrng( )
{
    return  "异常抛出  ！";
}
}