This week's book giveaway is in the OCAJP forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide 1Z0-808 and have Jeanne Boyarsky & Scott Selikoff on-line! See this thread for details.
I posted this question in this section because the webpage containing this feature is generated by a JSP page.
I'm going to move this to the HTML forum because the fact that a JSP was used to generate the page is moot. Once it gets to the browser, it's an HTML page like any other, and there is no JSP mechansim that is applicable to this issue.
You basically are either going to have to use an applet or add multiple file upload fields. Problem with the file upload field is it contains strict security since an evil person could grab files that you would not want to be uploaded.