Looking for an open source xml editor

I am looking for an opensource xml editor, preferrably written in Java
(hence the reason I am asking here). I would like for it to have
"add", "change", "delete" capabilities and at the same time maintain
well-formedness. You might recognize this idea from a thread I
started a long time ago in c.l.j.g but I don't have the skills to
write this app and would rather find an open source solution and
modify it. I can't use any of the commercial products like XML Spy,
and any application I use must be able to run on Windows XP and modify
an xml file on a networked drive.

Now I imagine most of you are going to say GIYF, and I know this.
But rather than spending hours searching, I was hoping someone on this
ng would have a recommendation for me.

Please note: I am not multi-posting or cross-posting so the only rule
I'm breaking is not searching for myself. But as I explained, I would
rather rely on the experience of those here than have to waste time
plodding around the web evaluating a plethora of products.

There is no need for anyone to do any searches. If I am not willing
to spend my time doing them, I certainly don't expect you to. All I
need are a couple of good ideas that people have run across in the
past. I'll take it from there.

Thank you.