You’d be better off using the get() method.
futureOne.get();
futureTwo.get();
Both of which wait for notification from the thread that it finished processing, this saves you the busy-wait-with-timer you are now using which is not efficient nor elegant.
As a bonus, you have the API get(long timeout, TimeUnit unit) which allows you to define a maximum time for the thread to sleep and wait for a response, and otherwise continues running.
See the Java API for more info.