Timeouts are not provided by the @Async annotation, since the timeout should be decided by the caller of the function, not the function itself.
I'm assuming you're referring to the timeout on an @Async-annotated method which returns a result. Such methods should return an instance of Future, and the get() method on Future is used to specify the timeout.
e.g.
@Async
public Future<String> doSomething() {
return new AsyncResult<String>("test");
}
and then
Future<String> futureResult = obj.doSomething(); // spring makes this an async call
String result = futureResult.get(1, TimeUnit.SECOND);