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

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 1897 times

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

If you enjoyed this post, please consider leaving a comment or subscribing to the RSS feed to have future articles delivered to your feed reader.

Leave a Comment


You might be Interested in these Posts

How to get the Number of Elements in an Array in C# ?

You can use the Length property of the array to return the number of elements in it. Note that once ...

How to get the Machine Name from a .NET Application using C# ?

You can use the MachineName property defined in the System.Environment class in order to get the Mac...

How to append an array to another in JavaScript ?

In JavaScript , you may want to append one array to another array(s) to combine their elements resul...