Return @Async method result in Spring MVC and return it to Ajax client

I Have some method inside my Controller which executes @Async task

@Async
public Future<String> getResultFromServer(){
    String result = ......
    return new AsyncResult<String>(result);
} 

The method execution time is up to 1o minutes. All I need to do is just to return result to client side which will be connected using AJAX/JQuery.

I don't want the client to request my server every second whether @Async method executed or not. I just want to keep my connection open and then just "push" result to Server.

@RequestMapping(value="/async.do", method=RequestMethod.POST)
public void getResult(HttpServletResponse res){
    String result = null;
    PrintWriter out = res.getWriter();
    Future<String> future = getResultFromServer();
    try {
        if (future.isDone())
            result = future.get();
        out.println(result);
        out.close();
    } catch (InterruptedException e) {
        e.printStackTrace();
    } catch (ExecutionException e) {
        e.printStackTrace();
    }
}

I understand that this very close to Comit model, but I'm not familiar with comet in general.

My question is how can I keep connection open on client side using JavaScript/JQuery?

and will my @RequestMapping(value="/async.do", method=RequestMethod.POST) method push result to the client?