Reading an old J2EE book, I encountered the "J2EE Application Client" (bundled in an EAR, with deployment descriptor and required libraries). I didn't have knowledge of such a client type (and it doesn't appears in Sun's J2EE 5 tutorial).
Does it still exists in J2EE 5? Is it used in the real world ? Do I have to install the SDK on every client machine in order to run the application client with the runclient command ? Is it part of SCEA5?
Sometimes enterprise applications use a standalone client application for handling tasks such as system or application administration. For example, a web-based banking application might use an application client to manually administer customers and accounts. This capability is useful in the event the site becomes inaccessible for any reason or a customer prefers to communicate things like changes to account information by phone.
The Java 2 Enterprise Edition (J2EE) reference implementation provides a way for you to write, test, and deploy application clients. A J2EE application client is a standalone program launched from the command line or desktop, and typically accesses Enterprise JavaBean programs running on the J2EE application server.