You need to return a Callable<> if you want spring.mvc.async.request-timeout=5000 to work.
@RequestMapping(method = RequestMethod.GET)
public Callable<String> getFoobar() throws InterruptedException {
return new Callable<String>() {
@Override
public String call() throws Exception {
Thread.sleep(8000); //this will cause a timeout
return "foobar";
}
};
}