Building Blocks - Java Concurrency in Practice - page 111

FutureTask is used by the Executor framework to represent asynchronous tasks, and
can also be used to represent any potentially lengthy computation that can be started before
the results are needed. Preloader in Listing 5.12 uses FutureTask to perform an ex-
pensive computation whose results are needed later; by starting the computation early, you
reduce the time you would have to wait later when you actually need the results.