我正在阅读Sierra Kathe SCJP 6的书，我陷入了矛盾之中： 
 
 最重要的方法可以抛出更少或更少的异常。 仅仅因为被覆盖的方法“冒风险”并不意味着覆盖的子类'异常具有相同的风险。 底线：无论重写的方法声明什么，重写方法都不必声明它将永远不会抛出的任何异常。 
 
 意味着如果重写方法可以抛出异常，如果子类中的相同方法抛出了exeption，但在测试之后我发现它不可能出现任何异常，如Exception或SQLException或IOException。 但是对于一些例外的NullPointerException，它可以很好地工作 

I am reading the book of Sierra Kathe SCJP 6 and I fell into a contradiction:
 
The overriding method can throw narrower or fewer exceptions. Just because an overridden method "takes risks" doesn't mean that the overriding subclass' exception takes the same risks. Bottom line: an overriding method doesn't have to declare any exceptions that it will never throw, regardless of what the overridden method declares.
 
Mean that if the overriding method can throw an exception if the same method from the subclass threw the exeption, but after testing I found that its impossible for any exception as Exception or SQLException or IOException. But for some exception such NullPointerException it works perfectly

原文：https://stackoverflow.com/questions/28136651