I don't think you can precompile your jsps when jboss startsup. You can do it manually using Tomcat's jspc class before startup.
do you know if it is possible to precompile jsp file
with jetty (jboss 3.0.4) with a script ant file
In fact, it is interesting to check syntax error during
the generation of a war file and not during
execution of the jsp file.
jetty use jasper compiler class but i can't use it because it is just a class and not an application.
Check out the JBoss/Jetty FAQ at
About halfway down there is a discussion of how to get JSP precompilation done as part of an ant war build. It's a bit cryptic w/ some hyperlinks to CVS diffs that show you an example, but if you work through it it definitely shows you a workable way to get this done. All my company's war builds now follow this pattern.
Have you tried asking on the jetty mailing list ?