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Try With Multiple Catch Blocks489

Given the following hierarchy of exceptions what will be the output of the program?

class AEx extends Exception
{
}

class BEx extends Exception
{
}

class CEx extends BEx
{
}

class TestExceptions
{
    public static void main(String s[])
    {
        try
        {
            System.out.println("Before A");
            methodA(false);
            System.out.println("Before B");
            methodB(true);
            System.out.println("Before C");
            methodC(false);
        }
        catch(AEx ax)
        {
            System.out.println("Exception A Occured");
        }
    }

    public static void methodA(boolean value) throws AEx
    {
        if(value) throw new AEx();
    }

    public static void methodB(boolean value) throws BEx
    {
        if(value) throw new BEx();
    }

    public static void methodC(boolean value) throws BEx
    {
        if(value) throw new CEx();
    }
}

A.	Before A Before B Before C
B.	Before A Before B Exception A Occured
C.	Compilation Error
D.	Runtime Error

Ans is C...Exception is an runtime error which wil cause an abnormal termination of the program..

we have Exception class Which is Child class of Throwble..
we have two type pf exceptions one is checked and Unchecked..
checked exceptions are checked at compile time only if they not handling than compiler wil raise an error, un checked exceptions wont checked by the compiler...

here we have 3 Exception classes named as AEx,BEx,CEx..all these classes are extending the Class Excpetion which checked exception..means all these 3 classes become Checked Exceptions..

Coming to the Program

we have three methods methodA(),methodB(),methodC() all these are taking boolean value as argument..these are static methods means we can call without creating the object..

we are calling methodA().by passing the arg as false,in methodA() if its true we are thrwoing the object of Class AEx..
throw--> it is an keyword which is used to throw an Exception object manually by the Programmer
throws--> it is keyword which is used to tel the caller of method should handle the exceptions iy any thing occurs in this method..here from main() we are calling all these method and these methods used throws keyword..means ew must handle it in main() while calling..in main() we put try catch mechanisam..in catch we wrote AEx means this try wil handle ony the exception type of class AEx..
methodA(false) here we not throwing any exception..
methodB(true) here we are throing BEx class Object which is Checked exception..but we use the keyword throws means caller must handle it..so the compiler wil check in main() we are not handling excpetion we wrote code to handle only AEx class exception not BEx..so Compiler wil gv erroe..Bcz it is checked Exception

in methodC(false) we are not thrwoing any Exception by we are using throws keyword by saying throws BEx...means caller should handle the BEx exception bt we are not handling so Error wil give at this line also

Posted by Uday Kumar 2014-10-10 12:18:36

Try With Multiple Catch Blocks489

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