BIT STUFFING IN JAVA WITH SOURCE CODE AND DESCRIPTION

Bit Stuffing is one of the framing technique used in Data-Link Layer (layer 2) of OSI Reference Model.
  In Bit-Stuffing technique, stuffing is done at the bit level. It was developed for the once very popular HDLC(High-Level Data Link Layer) protocol. Each frame begins and ends with a special bit pattern 01111110 or 0x7E in hexadecimal. This pattern is a flag byte.

"Whenever the sender's data link layer encounters five consecutive 1s in the data, it automatically stuffs a 0 bit into the outgoing bit stream" 
     "Whenever the receiver sees five consecutive incoming 1 bits, followed by a 0 bit, it automatically destuffs (i.e, deletes) the 0 bit."

For Example: 

If the user data contain the flag pattern, 01111110, this flag is transmitted as 011111010 but stored in the receiver's memory as 01111110, as shown in fig below:

fig.a) Original Data. b) Stuffed Data. c) Received Data

Source Code

import java.util.*;

public class SEFBS

                {

       public static void main(String[] args)

                                   {

              System.out.print("Enter the Binary message: ");

              Scanner sn=new Scanner(System.in);

              String data = sn.nextLine();

              String res = new String();

              String out=new String();

              int counter = 0;

              for(int i=0;i<data.length();i++)

                {

                   

                   if (data.charAt(i)!='1' && data.charAt(i)!='0')

                        {

                            System.out.println("Enter only Binary values!!!");

                            return;

                        }

                   if(data.charAt(i) == '1')

                        {

                            counter++;

                            res = res + data.charAt(i);

                        }

                   else

                        {

                            res = res + data.charAt(i);

                            counter = 0;

                        }

                   if(counter == 5)

                        {

                            res = res + '0';

                            counter = 0;

                        }

                }

            String inc="01111110"+res+"01111110";

            System.out.println("The Message to be transfered: " +inc);

            System.out.println("Seding Message....");

            counter=0;

            for(int i=0;i<res.length();i++)

                {

                   

                    if(res.charAt(i) == '1')

                        {

                            

                            counter++;

                            out = out + res.charAt(i);

                           

                        }

                    else

                        {

                             out = out + res.charAt(i);

                             counter = 0;

                        }

                   if(counter == 5)

                        {

                              if((i+2)!=res.length())

                              out = out + res.charAt(i+2);

                              else

                              out=out + '1';

                              i=i+2;

                              counter = 1;

                        }

               }

          

             System.out.println("Message Recevied...Successfully!!!");

             System.out.println("The Destuffed Message is: "+out);

       }

}

Output