code: private Properties loadMessages(String fileOrUrl) {
          URL url = ClasspathUtils.locateOnClasspath(fileOrUrl);
          if (url != null) {
              try (InputStreamReader reader = new InputStreamReader(url.openStream(), StandardCharsets.UTF_8)) {
                  Properties messages = new Properties();
                  messages.load(reader);
                  return messages;
              } catch (IOException e) {
                  log.error("Failed to load {}", fileOrUrl, e);
              }
          }
  
          return null;
      }
docs: Attempts to load a message resource.