When Jetspeed 2's auto-dispatching for edit_defaults mode option is turned on, JS2 would try to invoke doEdit() method directly without invoking render() method.
For this functionality, Jetspeed-2 tries to know if the portlet is extending GenericPortlet and if it has public doEdit() method. (See https://issues.apache.org/jira/browse/JS2-634 for details.)
However GroovyPortlet does not extend GenericPortlet, differing from other bridges. So, this new feature would not work for Groovy portlets.
Therefore, GroovyPortlet need to extend GenericPortlet and have public doEdit() method to support the new feature of JS2.