Upgrade to Jetty 9. 

Jetty 7 and 8 are in maintenance mode, Jetty 9 is recommended nowadays.

http://www.eclipse.org/jetty/

"The current recommended version for use is Jetty 9..."

Noticeable changes:

- Remove jetty-ajp, AJP no longer supported in Jetty.
- Implement filter-async using Servlet 3 async support instead of Jetty's proprietary Continuation API. Current implementation failed for NPE with Jetty 9's Continuation API.
- Jetty 9 no longer has a separate SSL handshake timeout. It always uses 'idle timeout'.