code: private void badRequest(HttpServletResponse res) throws IOException {
  		res.setContentType("text/html");
  		PrintWriter pw = res.getWriter();
  		pw.write(BAD_REQUEST);
  		pw.close();
  	}
docs: writes the Bad Request String in the Servlet response if condition falis
  
  @param res a {@link javax.servlet.http.HttpServletResponse} object
  @throws IOException