Take a thread dump to see where the Scanner thread is blocked.
How do I do that? Have you a WIKI reference?
In case anybody wants to know it looks like this was caused by embeded jars in my web application. It seems to be related to having different versions in different web applications.
I guess I should play with taking them out of the web applications. I avoided that in the past so
1. I wouldn't have to continually synchronise them
2. I had class loader problems if I put them in the server lib.
Jetty seemed to live with this fine but Tomcat seems to have problems.