[master] Changes for https://java.net/jira/browse/GRIZZLY-1543 (Future.get() may return null).
(cherry picked from commit 8603c2148b5f965feef760afdd0abcbc17f9ab97)
[master] Changes for https://java.net/jira/browse/GRIZZLY-1543 (Future.get() may return null).
remove FutureTask's code (related to callable) we don't need.(cherry picked from commit 288173248053f8e89dc9d2425a2a225e378c66a1)
[master] + one more update/optimization for for https://java.net/jira/browse/GRIZZLY-1543 (Future.get() may return null).
thanks to Aleksey Shipilev