code: private static InputStream getStreamFromClasspath(String fileName)
      {
          String path = fileName;
          InputStream dtdStream = PersistenceXMLLoader.class.getClassLoader().getResourceAsStream(path);
          return dtdStream;
      }
docs: Get stream from classpath.
  
  @param fileName
  the file name
  @return the stream
  @throws Exception
  the exception