Oracle already has a rich development environment within the JDeveloper tool set called ADF Faces. ADF is our banner name for our development frameworks (Application Development Framework). Currently the rich environment is ADF Faces.. and looks like this
However although the current framework contains some AJAX technologies we are working towards something much much richer, this is called ADF Faces Rich Clients (aka RIA).
This is all drag-n-drop, automatically refreshing etc. If your interested check out this sneak preview viewlet