docs: private String getMessage(String pContentType) {
          String fileName = responseMessageNames.get(pContentType);
  
          // Get cached value
          CacheEntry entry = responseCache.get(fileName);
  
          if ((entry == null) || entry.isExpired()) {
  
              // Create and add or replace cached value
              entry = new CacheEntry(readMessage(fileName));
              responseCache.put(fileName, entry);
          }
  
          // Return value
          return (entry.getValue() != null)
                  ? (String) entry.getValue()
                  : DEFUALT_RESPONSE_MESSAGE;
      }