Refactored

createID.java

public static String createId() {
  // Test by mocking `checkConfigs()` and make
  // sure `generateRandomId()` is called
  if (!checkConfigs()) {
    return generateRandomId();
  }
    
  HttpURLConnection connection = accessProv();
  try {
    // Test in two ways:
    // 1. Mocking `checkSiteResponse` and make 
    //    sure `generateId(connection)` is called
    // 2. Mocking `checkSiteResponse`, throw
    //    the exception, and make sure `null`
    //    is returned. Alternatively also check
    //    that code in the `catch` is run.
    if (checkSiteResponse(connection)) {
      return generateId(connection);
    }
  } catch (IOException e) {
    LOG.error("IOException");
  }
  
  return null;
}