@ApiOperation(value = "OAuth2 SignIn/SignUp (Apple)")
	@ApiResponses(value = {@ApiResponse(code = 200, message = "Success", response = TokenResponse.class),
			@ApiResponse(code = 401, message = "Unauthorized"),
			@ApiResponse(code = 403, message="Forbidden"),
			@ApiResponse(code = 404, message = "Not Found"),
			@ApiResponse(code = 500, message = "Failure")})
	@GetMapping("oauth2/apple")
	public ResponseEntity<Response> appleSignUpIn(@RequestParam(value = "authorizationCode") String authorizationCode, @RequestParam(value = "roleIdentifier", required = false) RoleIdentifier roleIdentifier , @RequestParam(value = "referralCode",required = false) String referralCode) throws NoSuchAlgorithmException, InvalidKeySpecException {
		AppleUser appleClaims;
		UriComponentsBuilder builder;
		ObjectMapper objectMapper = new ObjectMapper();
		if (referralCode != null) {
			Response response = this.loginService.validateReferralCode(referralCode);
			if (!response.isSuccess()){
				return new ResponseEntity<Response>(response,response.getStatus());
			}
		}
		String jwt = null;
		AuthorizationTokenResponse authorizationTokenResponse = null;
		try {
			jwt = appleVerifyAuthorizationService.generateJWT();
		} catch (Exception e) {
			e.printStackTrace();
			logger.error(e.getLocalizedMessage());
			return Response.getResponseData(false,"Could not generate JWT from private key.",null);
		}
		try {
			authorizationTokenResponse = appleVerifyAuthorizationService.getAuthTokenFromApple(jwt,authorizationCode);
		} catch (JsonProcessingException e) {
			logger.error(e.getLocalizedMessage());
			e.printStackTrace();
			return Response.getResponseData(false,"JSON processing exception",null);
		}
		if (authorizationTokenResponse == null) {
			return Response.getResponseData(false,"Authorization Failed", null);
		}

		System.out.println(authorizationTokenResponse.getId_token());
		//Getting Apple User Code Starts Here
		IdTokenHeader idTokenHeaderNew = null;
		try{
			idTokenHeaderNew = objectMapper.readValue(appleUserService.decodeIdTokenAndGetHeader(authorizationTokenResponse.getId_token()), IdTokenHeader.class);
		} catch (JsonProcessingException exception) {
			return Response.getResponseData(false,"Invalid form of new id token.", null);
		}
		System.out.println("kid - " + idTokenHeaderNew.getKid());
		//
		builder = UriComponentsBuilder.fromHttpUrl(appleConstants.getApplePublicKeyUri());
		Key key = appleUserService.getActualKeyOfApple(builder,idTokenHeaderNew.getKid());
		if (key == null) {
			return Response.getResponseData(false,"kId does not match with Apple.",null);
		}
		PublicKey publicKey = appleUserService.createAppleKeyToPublicKey(key);

		Claims claims = appleUserService.getClaims(publicKey, authorizationTokenResponse.getId_token());
		if (claims == null) {
			return Response.getResponseData(false,"Claims generation failed.",null);
		}
		System.out.println("CLAIMS ->>>>" +claims);
		appleClaims = appleUserService.getAppleClaimsFromClaims(claims);
		if (appleClaims == null) {
			return Response.getResponseData(false,"Could not retrieve Apple User",null);
		}
		logger.info(appleClaims.getEmail() + " successfully logged via apple login.");
		User prevUser = loginService.findByEmail(appleClaims.getEmail());
		if (prevUser == null && roleIdentifier == null) {
			return Response.getResponseData(false,"Looks like you don't have an account with us. Please click sign up to create a new account.",null);
		}

		User user = this.loginService.saveAppleUser(appleClaims.getEmail(), roleIdentifier,referralCode);
		if(user.getStatus()==UserStatus.BANNED) {
			return Response.getResponseData(false,"User is banned from the system.", null);
		}

		final UserDetails userDetails = customUserDetailsService.loadUserByUsername(user.getEmail());
		String accessToken = tokenProvider.generateToken(userDetails);

		return Response.getResponseData(true,"User Logged in",new TokenResponse(accessToken,refreshTokenService.createRefreshToken(user.getId()).getToken(),user) );

	}

<!---------------------------------------------------------------------------------------------------------------->

@Service
public class AppleUserService {

    public Key getActualKeyOfApple (UriComponentsBuilder uriComponentsBuilder, String keyIdentifierFromApp) {
        RestTemplate restTemplate = new RestTemplate();
        UriComponentsBuilder builder;
        ApplePublicKeyResponse applePublicKeyResponse = restTemplate.getForObject(uriComponentsBuilder.toUriString(),ApplePublicKeyResponse.class);
        List<Key> appleKeys = applePublicKeyResponse.getKeys();
        Key actualKey = null;
        for (Key key : appleKeys) {
            if (key.getKid().contentEquals(keyIdentifierFromApp)) {
                actualKey = key;
            }
        }
        return actualKey;
    }

    public PublicKey createAppleKeyToPublicKey(Key applePublicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        var modulus = new BigInteger(1, java.util.Base64.getUrlDecoder().decode(applePublicKey.getN()));
        var exponent = new BigInteger(1, java.util.Base64.getUrlDecoder().decode(applePublicKey.getE()));
        return KeyFactory.getInstance(applePublicKey.getKty()).generatePublic(new RSAPublicKeySpec(modulus, exponent));
    }

    public Claims getClaims(PublicKey publicKey, String idToken){
        try {
            Claims claims = Jwts.parser().setSigningKey(publicKey).parseClaimsJws(idToken).getBody();
            return claims;
        } catch(Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    public AppleUser getAppleClaimsFromClaims(Claims claims) {
        String iss = claims.get("iss", String.class);
        String aud = claims.get("aud", String.class);
        Date exp = claims.get("exp", Date.class);
        Date iat = claims.get("iat", Date.class);
        String appleIdentifier = claims.get("sub", String.class);
        String atHash = claims.get("at_hash", String.class);
        Long authTime = claims.get("auth_time", Long.class);
        String email = claims.get("email", String.class);
        String emailVerified = claims.get("email_verified", String.class);
        return new AppleUser(iss,aud,exp,iat,appleIdentifier,atHash,authTime,emailVerified,email);
    }

    public String decodeIdTokenAndGetHeader(String idTokenJWT){
        String[] split_string = idTokenJWT.split("\\.");
        String base64EncodedHeader = split_string[0];
        String base64EncodedBody = split_string[1];
        Base64 base64Url = new Base64(true);
        String header = new String(base64Url.decode(base64EncodedHeader));
        System.out.println(header);
        String body = new String(base64Url.decode(base64EncodedBody));
        return header;
    }

}