Here's what I finally did, after about 13 hours of tinkering, and it
worked:

http://plugindoc.mozdev.org/faqs/java.html

---quote---
Mozilla 1.4 and later, and Mozilla Firefox, are compiled with gcc 3.x.
A gcc 3.x compatible version of the Java plugin must be used. JRE 1.4.2
and later contain a compatible plugin.

If you installed the JRE 5.0 RPM, this plugin is
/usr/java/j2re1.5.0/plugin/i386/ns7/libjavaplugin_oji.so - and to
install it for Mozilla (including Mozilla Firefox), do the following:

Open a terminal
Change to your Mozilla (or Mozilla Firefox) plugins directory
Issue the following command: ln -s
/usr/java/j2re1.5.0/plugin/i386/ns7/libjavaplugin_oji.so
If you install your JRE in a different way (self extracting package,
debian package, etc), libjavaplugin_oji.so will quite likely be in a
different location. Do not just blindly use the command listed above!

In JRE 1.4.2, this file was in plugin/i386/ns610-gcc32
---unquote---

JRE 1.4.2 did not work for me. JRE RPM 5.0 update 1 did. Also, I had
been simlinking the 5.0 version to the old path for
libjavaplugin_oji.so. The above instructions worked for me perfectly.

avi-j@pacbell.net wrote:
> OK, this one has me stumped. I have tried in vain to install a
working
> J2RE plugin for Firefox under Fedora FC3 Linux. I have tried:
>
> -The Blackdown version
> -The IBM version
> -The Sun Version 1.4.2_03, 1.4.2_06, and 1.5 as JRE
> -The Sun Version as JDK
>
> I make the .bin executable, unpack the RPM, run the RPM, create the
> simlink in the Firefox plugins folder, create the java.sh, and when I
> do aboutlugins in Firefox, I can see all the java plugins. But when
I
> access a site with an Applet, Firefox implodes. This happens when I
do
> the same thing for the Mozilla browser.
>
> I've googled this thing backwards and forwards, checked all the Linux
> forums, and there are a lot of people with the same problem. None of
> the solutions offered have worked for me.
>
> Suggestions?
>
> THANKS!
>
> Oh, and if this is more suitable to another group (or if my crosspost
> is blatantly inappropriate), please let me know!