I don't know Java. Java has absolutely nothing to do with JavaScript other than they share a similar name. This particular forum is only for JavaScript.
Besides that, all you need is basic HTML.
Like I said, this only works under Windows with Internet Explorer (because Microsoft designed it that way), so understanding that, I'll explain.
Here is a basic, BASIC example:
<html>
<body>
<a href="file:///c:/">Click to view your hard drive</a>
</body>
</html>
Keep in mind that this will not let you see anyone elses hard drive, it will only allow each person to see their own hard drive.
Hopefully, this helps. =)