Since I received no positives answers to my last question. I will try to write a Java FTP upload applet myself.
My question is: "Can you recommend a Java FTP client library for me to use?"
I want it to be:
I found this overview of some libraries, but since this article is from 2003, maybe some new developments have happened :)
Check out Apache commons-net, which contains FTP utilities. Off the top of my head I'm not sure if it meets all of your requirements, but it's certainly free!