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Posted 5 Jul 2012

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# IMEI Validator using Java Swing

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How to create a simple IMEI validator application using Java Swing

## Introduction

This document covers how to create a simple IMEI validator application using Java Swing.

## IMEI Number

IMEI stands for International Mobile Equipment Identity. IMEI is used to identify a mobile device when it is connected to a network. Each GSM, CDMA, or satellite mobile has a unique IMEI number. This number will be printed in the device inside the battery component. A user can find his device IMEI number by calling “*#06#”. IMEI is a 15 digit number and the last digit is called as “Check Digit” and it can be identified by using Luhn algorithm.

## Luhn Algorithm

Luhn algorithm is also known as “Modulus 10” algorithm. It is a simple checksum formula used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers in US and Canadian Social Insurance Numbers. It was created by IBM scientist Hans Peter Luhn. Verification is done by validating check digit.

1. Double the value of every second digit from the right end (first right will be check digit number).
2. Add the individual digits comprising both the products from step (1) and unaffected digits in the original number.
3. If the total modulo 10 is equal to 0, then the number is valid, else it is not valid.

A simple example: IMEI no of mobile-354557030810924

### Step 2

`3+1+0+4+1+0+5+1+4+0+6+0+1+6+1+0+9+4+4=50`

### Step 3

`50%10=0`. So the above number is a valid number.

## Steps to Develop the Application

1. Open Eclipse and create a new Java project.

2. Name the project as `ImeiValidator` and click Finish.

3. Now open Package explorer and right click on `ImeiValidator`.

4. Create new class called `Imeivalidator`.

5. Write the following code in the class:
Java
```import javax.swing.*;
import java.awt.BorderLayout;
import java.awt.event.*;

public class Imei {
JFrame frame;
JButton button;
JTextField field;
JLabel label;
JLabel warninglabel;
Box panel;

public static void main(String[] args) {
Imei hl=new Imei();
hl.gui();
}
public void gui(){

panel = Box.createVerticalBox();
frame=new JFrame();
button=new JButton("Click");
field=new JTextField(15);
field.putClientProperty("JComponent.sizeVariant", "mini");

label=new JLabel("Enter the IMEI Number");
warninglabel=new JLabel("");

frame.setVisible(true);
frame.setSize(300,300);

}
public class buttonAction implements ActionListener{
public void actionPerformed(ActionEvent ev) {
int sum=0;
String ImeiNo=field.getText();
if (ImeiNo.length()!=15){
warninglabel.setText("IMEI Number should contain 15 characters");
}else
{
boolean errorflag = false;
for(int i=0;i<=14;i++){
//getting ascii value for each character
char c=ImeiNo.charAt(i);
int number=c;
//Assigning number values to corresponding ASCII value
if (number<48 || number>57){
warninglabel.setText("Enter only numerals");
errorflag = true;
break;
}else
{
switch(number){
case 48: number=0;break;
case 49: number=1;break;
case 50: number=2;break;
case 51: number=3;break;
case 52: number =4;break;
case 53:number =5;break;
case 54:number=6;break;
case 55:number=7;break;
case 56:number=8;break;
case 57:number=9;break;
}
//Double the even number and divide it by 10.
if ((i+1)%2==0){
number=number*2;
number=number/10+number%10;
}
sum=sum+number;
}
}
// Check the error flag to avoid overWriting of Warning Lable
if(!errorflag){
if(sum%10==0){
warninglabel.setText("Valid");
}
else
{
warninglabel.setText("Invalid");
}
}
}
}
}
}```

6. Now run the application by Run->Run As->Java Application.

7. The following window will get displayed:

8. Enter the IMEI number and click ‘Click’ as shown below:

## History

• 5th July, 2012: Initial version

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 Technical Lead EF (Education First) India
I graduated as Production Engineer and started my career as Software Developer then worked as tester for a while before moving into Windows application development using Microsoft Technologies. But for the last few years i am working on javascript, React, Node, AWS, Azure Chatbots