I'm sorry, if my questions looks naive. recently during a technical discussion, one of our architect referred about using Java Enterprise Server in his organization. He said, we're using it since 3-4 years.
As far as Application servers from Sun microsystem are concerned, I knew about Glassfish, but I never heard that Sun has anoy other release on Application server front.
Do you know more about Java Enterprise Server (or JES) that are being used as application servers for web application?
JES isn't a known acronym for Java Enterprise Server. JES used to be Sun "Java Enterprise System" which was a suite of various servers including an application server (Sun Java System Application Server). SJSAS was later renamed Glassfish so your architect is probably just using an older release of what is now know as Glassfish.
Otherwise, JES Web Server happened to be kind of an application server too (more precisely a servlet container like tomcat) so that might be what he referred to as JES.