<p>To be able to upload large files from a HTML page to a FTP server, I am looking for a Java/Flash FTP upload applet.</p>

<p>I really like the way <a href="http://www.dhtmlx.com/docs/products/dhtmlxVault/index.shtml" rel="noreferrer">dhtmlxVault</a> works, but I need it to upload to a FTP server instead of a HTTP file upload.</p>

<p>It would be really nice if the applet has no GUI of it's own, but instead is fully scriptable using Javascript so I can use HTML/CSS for it's appearance.</p>

<p>I hopefully looked into <a href="http://developer.yahoo.com/yui/uploader/" rel="noreferrer">Yahoo!'s YUI Uploader</a> since it requires Flash, but the documentation only mentions HTTP upload and no FTP upload.</p>

I tried the
ZUpload
Java applet.
Pro's:
The user interface works as easy as I could hope it to work.
It is a Java applet with it's own GUI, but I was able to implement some Javascript callbacks in it to update progress information in HTML. I would be able to minimize the GUI further.
Con's:
When an upload failes (when the FTP server tells it it is to busy, please retry in a moment) it thinks the upload succeeded and goes on with the next file. I tried to catch the exceptions but was unable to do so because of either the way j-ftp is used in the applet or my own lack of knowledge.
The project seems to be dead since 2003, so I don't expect any updates.
So my conclusion it that it is not ready to be used in a production environment. I still need a better solution.