1. Caller statement: OAuthService
2. PrivateKey privateKey = encryptionUtilities.string2PrivateKey(strPrivateKey);
3.             long startTime = System.currentTimeMillis();
4.             String accessToken = jwtHelper.generateToken(payload, privateKey, tokenExpirationInMilliSeconds);
5.             LOGGER.info("Time spend in getOauthToken jwtHelper.generateToken {}", System.currentTimeMillis() - startTime);
6.  
7.  
8. EncryptionUtil.java
9. public PrivateKey string2PrivateKey(String privateKeyString) {
10.         long startTime = System.currentTimeMillis();
11.         try {
12.             KeyFactory kf = KeyFactory.getInstance(ServiceConstants.RSA);
13.             PKCS8EncodedKeySpec keySpecPKCS8 = new PKCS8EncodedKeySpec(Base64.getDecoder().decode(privateKeyString));
14.             PrivateKey privateKey = kf.generatePrivate(keySpecPKCS8);
15.             LOGGER.info("Time spend in string2PrivateKey {}", System.currentTimeMillis() - startTime);
16.             return privateKey;
17.         } catch (IllegalArgumentException | InvalidKeySpecException | NoSuchAlgorithmException e) {
18.             LOGGER.error(e.getMessage(), e);
19.             return null;
20.         }
21.     }
22.  
23.