For having it work, it's necessary to have in the plugin directory
of your prowser a symbolic link to a file which name would be
libjavaplugin_oji.so
Personnally I had troubles and fought a lot for getting out of it.

In France we have (and I suppose it also exist in a lot of countries)
a secure system fo credit card payments, called e-CB here. Via internet
logged to a special service of your bank you create a virtual card
with legal number, ending date, control number exactly like a real
and it just works once for just one amount, and it is paid from your
real card account. But for internet payments it's very secure, since
the number is valid just once, and it's impossible to overpay, the
maximum is what you chose when creating.

Well for that system be able to work, it's mandatory to have
Java and Flashplayer working on your browser. The only way I
found was to make such symbolic link

You set your terminal in the directory where browser plugin is
example : "cd /usr/lib/firefox-3.0.13/plugins/"
Then you type your symbolic link command pointing to the
directory from which you need the symbolic link
example :
sudo ln -sf /opt/jre1.6.0_14/plugin/i386/ns7/libjavaplugin_oji.so