Upgrading from 7.2 to 7.5/8.0 caused the following code to freeze/hang all requests to the created instance indefinitely.
If you explicitly start the QueuedThreadPool instance before starting the server instance it will work. This seems very odd, since the thread pool is started in AbstractConnector.doStart().
Attached is a maven project with a test case that reproduces the problem.
JETTY-1428 seems to be the same issue, but it was dismissed because a custom built threadpool was used.