Please help me to understand this snipped of code ?

please refer the URL at http://www.javaworld.com/javaworld/jw-02-2009/jw-02-servlet3.html?page=2

following is code listing from above mentioned URL

@WebServlet(name="myServlet", urlPatterns={"/slowprocess"}, asyncSupported=true)
public class MyServlet extends HttpServlet {
   
    public void doGet(HttpServletRequest request, HttpServletResponse response) {
        AsyncContext aCtx = request.startAsync(request, response); 
        ServletContext appScope = request.getServletContext();
        ((Queue<AsyncContext>)appScope.getAttribute("slowWebServiceJobQueue")).add(aCtx);
    }
}

@WebServletContextListener
public class SlowWebService implements ServletContextListener {

public void contextInitialized(ServletContextEvent sce) {
        Queue<AsyncContext> jobQueue = new ConcurrentLinkedQueue<AsyncContext>();
        sce.getServletContext().setAttribute("slowWebServiceJobQueue", jobQueue);
        // pool size matching Web services capacity
        Executor executor = Executors.newFixedThreadPool(10);
        while(true)
        {
            if(!jobQueue.isEmpty())
            {
                final AsyncContext aCtx = jobQueue.poll();
                executor.execute(new Runnable(){
                    public void run() {
                        ServletRequest request = aCtx.getRequest();
                        // get parameteres
                        // invoke a Web service endpoint
                        // set results
                        aCtx.forward("/result.jsp");
                    }                    
                });             
            }
        }
    }
    
    public void contextDestroyed(ServletContextEvent sce) {
    }
}

can somebody just explain this code. not be line by line just the important parts. i shall be very grateful
Regards

What is it that you don't understand from the article from which this code comes from? You surely don't expect anyone to start from scratch when that article already exists?