throwing exceptions

[sin sai]

when "main method" throws an exception, where is the exception thrown to and who catches the exception?
example:

public static void main(String args[]) throws Exception {
  System.out.println("Hello World");
}

sin sai

[Jeff Bosch]

I don't believe you can catch that exception.
To catch an exception, you need a try-catch block, which must be declared inside a method. The JVM calls main(), not another class, so where could you put try-catch? I guess, technically, the JVM would "catch" the exception by terminating your program and printing a stack trace, but it would do that anyway, so why type the extra code?
The declaration is legal, but I don't think it's particularly useful.

[Kevin Hooke]

It will be uncaught, and like Jeff said, the JVM will terminate your application. If you don't want this to happen, then you should catch any exceptions you are expecting within the main() method and handle them appropriately, to avoid your app abnormally ending.
Kevin

[Jeff Bosch]

Thanks, Kevin. I was thinking of having main() inside a try-catch, which would be illegal. I think you're saying that the code could be modified to something like:

public static void main(String args[]) {
    try {
        System.out.println("Hello World");
        // other code that could throw Exception
    } 
    catch( Exception e ){
        System.err.println( "Oops! " + e )
    }
}

Now you're catching the exception, printing a stack trace, but not terminating the program.

[Anupam Sinha]

Hi Sin
Using throws in the main() method may be useful in case you yourself would like to call main() from your program. As in the program. But I guess that this approach is hardly used.

public class Test
{
private static boolean flag=true;

public static void main(String args[]) throws InterruptedException
{
if(flag)
{
callMain();
}
else
{
throw new InterruptedException();
}
}

public static void callMain()
{
String a[]=new String[1];
flag=false;
try
{
main(a);
}
catch(InterruptedException e)
{
System.out.println("Exception Caught");
}

}
}

[Jeff Bosch]

There is another possibility if you really need to catch Exception from main(): Have only one method call in main(), say, to doMainStuff().

public static void main(String args[]) {
    try {
        doMainStuff();
    }
     catch( Exception e ){
        System.err.println( "Oops! " + e )
    }
}
public static void doMainStuff() throws Exception {
    // do main() stuff
}

It's not pretty, but I think it would accomplish what Sin Sai seemed to be trying to do.