There was no opportunity before to develop Oracle ADF (Application Development Framework) applications on any open source application server such as Tomcat, or Glassfish while Glassfish is Oracle reference implementation now for JEE specifications, the only way is to develop on Oracle Weblogic app. server. Even using oracle enterprise pack (OEPE) for development on eclipse IDE. Nowadays oracle releases the ADF essentials. With the new Oracle ADF Essentials offering you can now deploy applications that leverage Oracle ADF on the open source Glassfish 3.1 server.