Servelt

[parag dandegaonkar]

please tell me in overriding why we can not throw broder exception

[Sebastian Janisch]

Hey,

first, please choose a meaningful title for your topic, as it's pretty obvious that it's about servlets if it's posted in the Servlets forum ;-)

Your question is more about Java in general. When overriding your method you may throw lesser, narrower, or no exceptions compared to the super class method. Having said that it is not possible to throw a broader exception in a servlet.

What you can do however is chain an exception meaning wrapping it in a servlet exception. That's common practice and looks like this.

try {
    ///
}
catch (StringIndexOutOfBoundsException e) {
    throw new ServletException(e);
}

[Bear Bibeault]

Please take the time to choose the correct forum for your posts. This forum is for questions on Servlets. For more information, please read this.

This post has been moved to a more appropriate forum.

[Rob Spoor]

parag dandegaonkar wrote: please tell me in overriding why we can not throw broder exception

Because calling code will not expect it. Consider this example:

class A
{
    public void doSomething() throws IOException
    {
        throw new IOException("Cannot do something");
    }
}

class B extends A
{
    @Override
    public void doSomething() throws Exception // broader exception
    {
        throw new SQLException("Still cannot do something");
    }
}

class C
{
    public static void main(String[] args)
    {
        A a = new B();
        try
        {
            a.doSomething(); // declares to throw only IOException
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        // but what if a.doSomething() actually throws the SQLException?
    }
}