Exceptions

[Lovleen Gupta]

Whats the use of having a return statement in a catch or finally block?
Basically, how does the rpogram flow, once it encounters a return statement?
For exp, in the program below, what will be the output if "Hello.txt" doesn't exist:

   import java.io.*;
public class Mine {
    public static void main(String argv[]){
Mine m=new Mine();
System.out.println(m.amethod());
    }
    public int amethod() {
try {
    FileInputStream dis=new FileInputStream("Hello.txt");
}catch (FileNotFoundException fne) {
    System.out.println("No such file found");
    return -1;
}catch(IOException ioe) {
} finally{
    System.out.println("Doing finally");
}
 
return 0;
    }
 

Thanks..

[Chandra Bhatt]

Hi Guptajee,

Posted By Lovleen Gupta
Whats the use of having a return statement in a catch
or finally block? Basically, how does the rpogram flow,
once it encounters a return statement?

Suppose,if exception is thrown, you want to make return statement,
and no other statement execution of the method to proceed. But finally
will execute for sure unless you write System.exit(1) or something that
terminates the program. Suppose you dont write "return -1;" in your catch
clause, even after exception comes, a line that may outside of the try catch
clause will execute and may yield undesirable result. So you wrote "return -1" there.

Got it?


Regards,
cmbhatt

[Lovleen Gupta]

Originally posted by Chandra Bhatt:
Hi Guptajee,



Suppose,if exception is thrown, you want to make return statement,
and no other statement execution of the method to proceed. But finally
will execute for sure unless you write System.exit(1) or something that
terminates the program. Suppose you dont write "return -1;" in your catch
clause, even after exception comes, a line that may outside of the try catch
clause will execute and may yield undesirable result. So you wrote "return -1" there.



Got it?


Regards,
cmbhatt

So, in this program, why is -1 printed and not 0?
Please explain.

Thanks.
[ April 12, 2007: Message edited by: Lovleen Gupta ]

[Chandra Bhatt]

Hey Gupta,

System.exit(0); //Normal termination of the program
System.exit(-1); //Supposed to be an abnormal termination of program

But as you return anything from the method, generally -1 shows that something
went wrong. You can even return 3, 13 , and 43 if you treat as it is abnormal
return from the method. (It is upto you). But general practice says negative returned value, something abnormal happened there.


Got it Guptajee?

Regards,
cmbhatt