I looked at the page www.oracle.com/.../af_tree.html
,in the attribute list i did not find the attribute to set it for right to left(Arabic) tree.
I have a idea from Richfaces ,in the Rich Drop DOwn Menu componenet that support Arabic(Right to Left) has attribute likes jointpont="tl" ,and setting style ="float:right" in panelgrid that contains Drop Down Menu,so we have the Menu that is in right side of page and opens from right to left.

I also download the demo(adf-richclient-demo.war) and istall it ,but i can not find anything useful.

Please go to http://mixiran.com/ ,in the 1/3 of page there is a Arabic component tree,i want something like that.
Does ADF support that or any other framework does?

Have u tested tree  component for Arabic in ADF?
If yes,so is it possible to say, which attributes u set?