Java program to check whether the number is IMEI Number or not

Program to check valid IMEI number in java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class CheckIMEINumber
{
	// Function for finding and returning sum of digits of a number
	int sumDig(int n) 
	{
		// initialise here.
		int a = 0;
	    while(n>0)
	    {
	    	a = a + n%10;
	        n = n/10;
	    }
	    return a;
	}
	     
	public static void main(String args[])throws IOException
	{
		// create object here.
		CheckIMEINumber ob = new CheckIMEINumber();
	    BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
	         
	    // The 'Long' data type is used to store 15 digits.
	    System.out.print("Enter a 15 digit IMEI code : ");
	    long n = Long.parseLong(br.readLine()); 
	         
	    // Converting the number into String for finding length
	    String s = Long.toString(n); 
	    int l = s.length();
	    
	    // If length is not 15 then IMEI is Invalid
	    if(l!=15) 
	    System.out.println("Output : Invalid Input");
	    
	    else
	    {
	    	int d = 0, sum = 0;
	        for(int i=15; i>=1; i--)
	        {
	        	d = (int)(n%10);
	                 
	        	if(i%2 == 0)
	            {
	        		// Doubling every alternate digit
	        		d = 2*d; 
	            }
	 
	        	// Finding sum of the digits
	        	sum = sum + ob.sumDig(d); 
	        	n = n/10;
	        }
	             
	        System.out.println("Output : Sum = "+sum);
	        
	        if(sum%10==0)    
	        	System.out.println("Valid IMEI Code");
	        else
	            System.out.println("Invalid IMEI Code");
	    }
	}
}

Output

First run:
Enter a 15 digit IMEI code : 111111111111111
Output : Sum = 22
Invalid IMEI Code

Second run:
Enter a 15 digit IMEI code : 474154203237518
Output : Sum = 60
Valid IMEI Code