Re: Exception Handling

From:
Jeff KE7NVY <unclejeff@verizon.net>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 10 Mar 2010 08:49:57 -0800 (PST)
Message-ID:
<3d5be5ce-2fbc-426d-bc20-e05723d3ca81@k6g2000prg.googlegroups.com>
On Mar 9, 9:53 pm, Javas <deepan...@gmail.com> wrote:

public class Qn24 {

        static class A
        {
                void process() throws Exception { throw n=

ew

Exception(); }
        }

        static class B extends A
        {
                void process() { System.out.println("B ")=

; }

        }

        public static void main(String[] args)
        {
                A a = new B();
                a.process();
        }

}

Why does the above code results in a compilation error? since it is
always invoking class B's process() method which doesnt throw any
exception.


Exception is a checked exception. That means that whenever you
declare
a method that (potentially) throws it, you must do one of two things
in
the code that calls that method. Either handle the exception by
putting
the call inside a try/catch block:

public static void main(String[] args) {
    A a = new B();
    try {
        a.process();
    }
    catch (Exception e) {
        System.out.println("main: Exception caught");
    }
}

Or, declare the calling method as also throwing Exception:

public static void main(String[] args) throws Exception {
    A a = new B();
    a.process();
}

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