Java EE (Java Enterprise Edition) General Discussion

Hi,
I need a treeview tag that is based on a hierarchy of java objects, like the jenkov tree (http://www.jenkov.dk/prizetags/introduction.tmpl), but unlike the jenkov tree is populated as a whole to html and javascript - which means expanding nodes doesn't cause a server roundtrip, all the data is present on the client html.
I'd be happy if someone can provide me with good opensource projects on this matter...
Thanks