Jasper triggers recompilation of JSPs if the timestamp on the .jsp file is newer than the .class file. This can lead to not recompiling when the JSP changes, if the timestamp of the new JSP is newer than the old JSP but not newer than the compiled version. The upstream bug is https://issues.apache.org/bugzilla/show_bug.cgi?id=33453. The change was made for Tomcat 7, but it may be possible to backport to JBossWeb 7
Asked for and refused a while ago: https://issues.jboss.org/browse/JBPAPP-8362 The fix adds complexity and I still don't see the point.
Thanks for the link, I was looking in JBPAPP6/WFLY/JBWEB and not JBPAPP. I'm happy to mark this WONTFIX then.