explain the code: $//$ import required classes and package, if any

import java.util.Scanner;

$//$ create class CaesarCipherExample for encryption and decryption

public class CaesarCipherExample

$\{$

$//$ ALPHABET string denotes alphabet from a$-$z

public static final String ALPHABET $=$ "abcdefghijklmnopqrstuvwxyz";

$//$ create encryptData$()$ method for encrypting user input string with given shift key

public static String encryptData$($String inputStr, int shiftKey$)$

$\{$

$//$ convert inputStr into lower case

inputStr $=$ inputStr.toLowerCase$()$;

$//$ encryptStr to store encrypted data

String encryptStr $=""$;

$//$ use for loop for traversing each character of the input string

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

$\{$

$//$ get position of each character of inputStr in ALPHABET

int pos $=$ ALPHABET.indexOf$($inputStr$.$charAt$($i$))$;

$//$ get encrypted char for each char of inputStr

int encryptPos $=($shiftKey $+$ pos$)\%26$;

char encryptChar $=$ ALPHABET.charAt$($encryptPos$)$;

$//$ add encrypted char to encrypted string

encryptStr $+=$ encryptChar;

$\}$

$//$ return encrypted string

return encryptStr;

$\}$

$//$ create decryptData$()$ method for decrypting user input string with given shift key

public static String decryptData$($String inputStr, int shiftKey$)$

$\{$

$//$ convert inputStr into lower case

inputStr $=$ inputStr.toLowerCase$()$;

$//$ decryptStr to store decrypted data

String decryptStr $=""$;

$//$ use for loop for traversing each character of the input string

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

$\{$

$//$ get position of each character of inputStr in ALPHABET

int pos $=$ ALPHABET.indexOf$($inputStr$.$charAt$($i$))$;

$//$ get decrypted char for each char of inputStr

int decryptPos $=($pos $-$ shiftKey$)\%26$;

$//$ if decryptPos is negative

if $($decryptPos $<0)\{$

decryptPos $=$ ALPHABET.length$()+$ decryptPos;

$\}$

char decryptChar $=$ ALPHABET.charAt$($decryptPos$)$;

$//$ add decrypted char to decrypted string

decryptStr $+=$ decryptChar;

$\}$

$//$ return decrypted string

return decryptStr;

$\}$

$//$ main$()$ method start

public static void main$($String$[]$ args$)$

$\{$

$//$ create an instance of Scanner class

Scanner sc $=$ new Scanner$($System$.$in$)$;

$//$ take input from the user

System.out.println$("$Enter a string for encryption using Caesar Cipher: $")$;

String inputStr $=$ sc$.$nextLine$()$;

System.out.println$("$Enter the value by which each character in the plaintext message gets shifted: $")$;

int shiftKey $=$ Integer.valueOf$($sc$.$nextLine$())$;

System.out.println$("$Encrypted Data $===>"+$encryptData$($inputStr$,$ shiftKey$))$;

System.out.println$("$Decrypted Data $===>"+$decryptData$($encryptData$($inputStr$,$ shiftKey$),$ shiftKey$))$;

$//$ close Scanner class object

sc$.$close$()$;

$\}$

$\}$