code: private static boolean isValidChallenge(String authenticateHeader, String authChallengePrefix) {
          if (authenticateHeader != null && !authenticateHeader.isEmpty()
                  && authenticateHeader.toLowerCase().startsWith(authChallengePrefix.toLowerCase())) {
              return true;
          }
          return false;
      }
docs: Verifies whether a challenge is bearer or not.
  
  @param authenticateHeader
  the authentication header containing all the challenges.
  @param authChallengePrefix
  the authentication challenge name.
  @return