合并可完整的期货

Question

我有这样的代码：

public class ProcessorService {
     @Autowired private AsyncService asyncService;

     public Void process() {
        List<CompletableFuture<List<MyEntity>>> futures = new ArrayList<>();
        for (i = 0; i < 3; i++) {
            futures.add(asyncService.getSomething());
        }

        List<MyEntity> flatList = sequence(futures); // compile error
     }

     private static <T> CompletableFuture<List<T>> sequence(List<CompletableFuture<T>> futures) {
        CompletableFuture<Void> allDoneFuture =
                CompletableFuture.allOf(futures.toArray(new CompletableFuture[futures.size()]));
        return allDoneFuture.thenApply(v ->
                futures.stream().
                        map(future -> future.join()).
                        collect(Collectors.<T>toList())
        );
    }
}

汇编错误是：

Required type: List<MyEntity>
Provided: CompletableFuture<List<List<MyEntity>>>

如何获得将单个期货中所有元素合并为一个元素的列表？