A {@code Future} represents the result of an asynchronous computation. Methods are provided to check if the computation is complete, to wait for its completion, and to retrieve the result of the computation. The result can only be retrieved using method {@code get} when the computation has completed, blocking if necessary until it is ready. Cancellation is performed by the {@code cancel} method. Additional methods are provided to determine if the task completed normally or was cancelled. Once a computation has completed, the computation cannot be cancelled. If you would like to use a {@code Future} for the sake of cancellability but not provide a usable result, you can declare types of the form {@code Future<?>} and return {@code null} as a result of the underlying task.
A {@link Future} that is {@link Runnable}. Successful execution of the {@code run} method causes completion of the {@code Future} and allows access to its results. @see FutureTask @see Executor @author Doug Lea @param (V) The result type returned by this Future's {@code get} method