Strangely that variable requestUri was used before it was checked ( file RootServlet.java, line 118 ) if (requestUri.equals("") || requestUri.equals("/") || requestUri == null) { It seems it should be if (requestUri == null || requestUri.equals("") || requestUri.equals("/") ) { This possible defect found by AppChecker (cnpo.ru/en/solutions/appchecker.php)