code: public TokenResponse callToken(
              MultivaluedMap<String, String> parameters, String clientId, String clientSecret,
              Property[] properties, String clientCertificate, String[] clientCertificatePath)
      {
          String params = URLCoder.formUrlEncode(parameters);
  
          return callToken(params, clientId, clientSecret, properties, clientCertificate, clientCertificatePath);
      }
docs: Call Authlete's {@code /api/auth/token} API.