Regarding Overriden method Exception----very urgent

Question

if we override a method , Is this method can throw a super class exception of overridden method...
i.e
class Base
public void show() throws Exception1
class Derived extends Base
public void show() throws Exception2
Is Exception 2 should be the subclass of Exceptio 1 or not.........is there any contraint...............bcz some conditions are working some are not working....
if question is not clear....let me know i will explain clearly

Answer 1

Information collected from the site:
The Overridden Method can throw either Same Exception or Subclass of that Exception defined the base class method.
Even if the base class method is throwing an Exception, it is not mandatory that the overridden method should throw any Exception (We can override that method without throwing any Exception)
Irrespecive of the Exception throws in the Base class method, Overridden method can throw any RuntimeException.
Reference: http://javalive.com/modules/articles/article.php?id=19
Case 1: this code giving compilation error ( as per the rule i.e overridden method exception should be subclass of base class method exception)
class Base
Public void test() throws NullPointerException
     System.out.println(�hello�);
Class Derived extends Base
     Public void test() throws Exception
     System.out.println(�hello�);
Case 2: this code is compiling properly, but it should give compile time error as per the rule�.Why.?
class Base
Public void test() throws NullPointerException
     System.out.println(�hello�);
Class Derived extends Base
     Public void test() throws RuntimeException
     System.out.println(�hello�);
}