code: private static ClientAuthenticationMethod firstSupportedMethod(final List<ClientAuthenticationMethod> metadataMethods) {
          Optional<ClientAuthenticationMethod> firstSupported = 
              metadataMethods.stream().filter((m) -> SUPPORTED_METHODS.contains(m)).findFirst();
          if (firstSupported.isPresent()) {
              return firstSupported.get();
          } else {
              throw new TechnicalException("None of the Token endpoint provider metadata authentication methods are supported: " + 
                  metadataMethods);
          }
      }
docs: The first {@link ClientAuthenticationMethod} from the given list of
  methods that is supported by this implementation.
  
  @throws TechnicalException
  if none of the provider-supported methods is supported.