Question

import java.util.*;

public class June16{
    public static void main(String[] args){
        Scanner kb = new Scanner(System.in);
        double b=0;
           boolean checkInput = true;
        do{
            try{
                System.out.println("Input b : ");
                b = kb.nextDouble();
                checkInput = false;
            }catch(InputMismatchException ime){
            }
        }while(checkInput);
    }
}

After InputMismatchException is thrown, why my program not prompt for input? 😀

Answer 1

From the documentation:

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.

This is why you end up in an infinite loop if you don’t enter a valid double. When you handle the exception, move to the next token with kb.next().