code: public void readLangs() {
          final ServletContext servletContext = AbstractServletListener.getServletContext();
  
          @SuppressWarnings("unchecked") final Set<String> resourcePaths = servletContext.getResourcePaths("/plugins/" + dirName);
  
          for (final String resourcePath : resourcePaths) {
              if (resourcePath.contains("lang_") && resourcePath.endsWith(".properties")) {
                  final String langFileName = StringUtils.substringAfter(resourcePath, "/plugins/" + dirName + "/");
  
                  final String key = langFileName.substring("lang_".length(), langFileName.lastIndexOf("."));
                  final Properties props = new Properties();
  
                  try {
                      final File file = Latkes.getWebFile(resourcePath);
  
                      props.load(new FileInputStream(file));
  
                      langs.put(key, props);
                  } catch (final Exception e) {
                      Logger.getLogger(getClass().getName()).log(Level.ERROR, "Get plugin[name=" + name + "]'s language configuration failed",
                              e);
                  }
              }
          }
      }
docs: Reads lang_xx.properties into field {@link #langs langs}.