I create a web application (WAR) and deploy it on Tomcat. In the webapp there is a page with a form where an administrator can enter some configuration data. I don\
WEB-INF is a good place to put your config file. Here's some code to get the absolute path of the directory from a servlet.
public void init(ServletConfig servletConfig) throws ServletException{ super.init(servletConfig); String path = servletConfig.getServletContext().getRealPath("/WEB-INF")