Starting a background thread in Tomcat

I have long running processes that repeatedly do something (like check a directory for new files or a database table for new records) then sleep for a while. These processes are deployed to Tomcat (giving me jsp interfaces for monitoring and any other requests).

Ideally the Tomcat container should manage this long running thread. i.e Tomcat should be aware of the background thread particularly for stopping a web application completely (stopping the background thread) but also for metrics gathering.

I implement long running threads as HttpServlets and start them in my ant build via the task which does an http get to the servlet url. We want the to return control to the build process and not wait for the long running thread to finish. The trick is to simply close the response output stream and continue. i.e.

    public abstract class RunnableServlet extends HttpServlet {

        private Runnable runnable;

        public RunnableServlet(Runnable runnable) {
            this.runnable = runnable;
        }

        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
            String command = req.getParameter("command");

            // continue with the task but with the container aware of this thread
            if ("start".equals(command)) {
                response.getOutputStream().write("started");
                response.getOutputStream().close();
                runnable.run();
            }
        }
    }

By the way to use the above servlet extend it!