code: public static void setContentTypeHeader(HttpResponse response, File file) {
  		String mimeType = MimeTypes.getMimeTypeForFileName(file.getName());
  		String mimeFinal = mimeType != null ? mimeType : MimeTypes.getDefaultMimeType();
  		response.headers().set(CONTENT_TYPE, mimeFinal);
  	}
docs: Sets the content type header for the HTTP Response.
  
  @param response HTTP response
  @param file     file to extract content type