I finally got this to work.

1. upload the java .class file and the .html file referencing the .class
file to the Swiki (they must be in the same directory).

2. Make a link to the html file in a manner similar to this:

<a href="/recipes/uploads/59/HelloColourSwirl.html">JAVA</a>

(here, recipes is the name of the swiki, 59 is the page to which both
files have been uploaded.)

Click on the link and, all things being equal, the java applet will
load. 

This works fine on Linux with Netscape 4.7* (Comanche 4.10), but there
are all kinds of security issues with IE and there may be operational
problems with the 6* series of Netscape.

Cheers

John
-- 
If you don't care about your data, like file systems which automagically
destroy themselves and have money to burn on 3rd party tools to keep
your
system staggering on, Microsoft (tm) have the Operating System for you.