code: private static InputStream openResource(final String file) throws IOException {
  		InputStream stream = HtmlConverterApplication.class.getResourceAsStream("/" + file);
  		if (stream == null) {
  			throw new FileNotFoundException(file);
  		} else {
  			return stream;
  		}
  	}
docs: Opens a resource from classpath.
  
  @param file
  Filename of resource
  @return Stream of given file
  @throws IOException
  Failed to open resource