Jun - you're question in regard to "why Java" etc is a good one, but perhaps it would be better to ask it over on one of Ars Digita's forums? After all, they're the folks who decided to use Java rather than continue with the Tcl version.
Ask here, and we'll mostly say, "I dunno, the Tcl version has served me well" and, like you, list sites we've developed with it :)
There's nothing wrong with asking here, it's just that the Java fans live elsewhere, i.e. at aD.
Feel free to post questions or requests for help with ns_xml here at openacs.org - probably in another thread so folks will see them more readily.
