There is a bug against Tomcat where, when a context is reloaded, its spawned threads continue, and die because they have an invalid classloader:

http://nagoya.apache.org/bugzilla/show_bug.cgi?id=3888

The symptom is errors like this:

WebappClassLoader: Lifecycle error : CL stopped

I'm not sure if this is a Tomcat bug, or user error (as the Tomcat developer maintains). We should test what happens to scheduled processes (like the PopService) when Tomcat reloads.