code: @Override
      public void start() {
          try {
              url = new URL(getStringSetting(SETTING_URL, DEFAULT_LIBRATO_API_URL));
  
              user = getStringSetting(SETTING_USERNAME);
              token = getStringSetting(SETTING_TOKEN);
              basicAuthentication = Base64Variants.getDefaultVariant().encode((user + ":" + token).getBytes(Charset.forName("US-ASCII")));
  
              if (getStringSetting(SETTING_PROXY_HOST, null) != null && !getStringSetting(SETTING_PROXY_HOST).isEmpty()) {
                  proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(getStringSetting(SETTING_PROXY_HOST), getIntSetting(SETTING_PROXY_PORT)));
              }
  
              libratoApiTimeoutInMillis = getIntSetting(SETTING_LIBRATO_API_TIMEOUT_IN_MILLIS, DEFAULT_LIBRATO_API_TIMEOUT_IN_MILLIS);
  
              source = getStringSetting(SETTING_SOURCE, DEFAULT_SOURCE);
              source = getStrategy().resolveExpression(source);
  
              logger.info("Start Librato writer connected to '{}', proxy {} with user '{}' ...", url, proxy, user);
          } catch (MalformedURLException e) {
              throw new EmbeddedJmxTransException(e);
          }
      }
docs: Load settings