Why my code runs to infinite loop when I enter a non-integer input?

Question

Why I'm having an infinite loop when I enter a non-digit token?

public class ExceptionHandling {
    static int i;
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        boolean b=true;
        Scanner in=new Scanner(System.in);
        while (b ==true) { 
            try{
                i=in.nextInt();
                b=false;
                // System.out.println("not executrd bcoz above exception");
            }
            catch(InputMismatchException e){      
                System.out.println(i);
            }     
        }            
    }
}

thats fine because u entering integer if u enter non integer exception should be there but it is going in finite loop after that. — Arjun Chaudhary, May 10 '15 at 10:20

score 2 · Answer 1 · answered May 10 '15 at 10:20

2

You're actually asking "why my code runs to infinite loop when I enter a non-integer input".

Well, you need to call in.next() in the catch clause to solve this. Why? See the Scanner docs:

When a scanner throws an InputMismatchException, the scanner will not pass the token that caused the exception, so that it may be retrieved or skipped via some other method.

answered May 10 '15 at 10:20

Maroun

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tahnks man somebody understood – Arjun Chaudhary May 10 '15 at 10:22
is there any other solution. – Arjun Chaudhary May 10 '15 at 10:43
@ArjunChaudhary Yes, you can reinitialize the scanner object in the `catch` clause: `in = new Scanner(System.in);` – Maroun May 10 '15 at 10:44
I think the problem is of extra tab that is after entering digits when we press Enter nextLine() read that and don't asks for input. – Arjun Chaudhary May 10 '15 at 11:01
@ArjunChaudhary tabs has nothing to do with Java. You can add 100000 tab, Java doesn't care. I already explained what's the problem. – Maroun May 10 '15 at 11:02

Why my code runs to infinite loop when I enter a non-integer input?

1 Answers1