Java – How to read a valid Integer number from Console ?

Published on March 2, 2016 by abundantcode

Filed under Java

Last modified March 2, 2016

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Problem Statement

You need to read a valid integer number from the Console in your java program. If the number is invalid , show appropriate message.


To read a valid integer from a console program , you can use the Scanner class and pass the as the parameter to its constructor. The scanner class exposes a method called nextInt() which can be used to find out if the number is a valid integer or not as shown below.

import java.util.InputMismatchException;
import java.util.Scanner;

public class Main {
    static Scanner helper = new Scanner(;
    public static void main(String[] args) {
       System.out.println("Please enter a valid integer for ");
       int retValue;
               retValue = helper.nextInt();
           catch(InputMismatchException ex)
               System.out.println("This is a invalid number at");
        System.out.println("You have entered an valid number");


Output of the above program is

Please enter a valid integer for


This is a invalid number at


You have entered an valid number

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