1/each SAR has its classloader. that enables
b- class visibility with unified CL
2/ yes but through simple class sharing and flat visibility
3/ lib classes are those that don't need reloading or hot deploy. You can run all of jboss from the lib stuff if you need. but working with /deploy allows you to have reloading.
hey, I don't mean to sound salesy but at this level of questions on classloading I would recommend you go to one of our trainings, either houston (in a week) for advanced or admin. Check the right bar for a training near you, you are ready for enlightement