The maintenance of the glassfish Jasper JSP code base has fallen behind apache's version. There are now several unfixed bugs in the glassfish version.
Thus I'd very much like to switch to using apache's jasper implementation, but we need to be a bit mindful of exactly how we do this as I don't want to break anything in a dot release - specially not changing any module names (as the whole point of jetty mods is to allow easy upgrade).
So here is the approximate plan that I'm considering.
In the 9.1.4 release (next week or two), we will add a apache-jsp mod, that can be used instead of the current jsp module to use the apache version of jasper. However, we will not change any of the hard JSP dependencies from the jetty-maven-plugin or the jetty-jspc-plugin, so they will continue to function normally, as will any distro/base that does not explicitly switch to apache-jsp.
I then think this is a high enough priority to make the next release after that a 9.2.0, which will allow us to make a switch to using the apache-jsp module by default in the distro and both plugins. We will then provide a glassfish-jsp mod that can optionally be used to switch back to glassfish JSP if you really want to.