The information presented here was taken from these posts (many thanks to the authors: scott_glaser & natousayni):
OpenJDK is the free implementation of Sun's Java run-time environment. The browser plugin used in Fedora 9, gcjwebplugin, does not yet support signed plugins. From the Fedora Project Wiki: :
Handling Java Applets
Upstream OpenJDK does not provide a plugin. The Fedora OpenJDK packages include an adaptation of gcjwebplugin, that runs untrusted applets safely in a Web browser. The plugin is packaged as java-1.6.0-openjdk-plugin.
- The gcjwebplugin adaptation does not support signed applets. Signed applets will run in untrusted mode. Experimental support for signed applets is present in the IcedTea repository, but it is not ready for deployment in Fedora.
- The gcjwebplugin security policy may be too restrictive. To enable restricted applets, run the firefox -g command in a terminal window to see what is being restricted, and then grant the restricted permission in the /usr/lib/jvm/java-1.6.0-openjdk-22.214.171.124/jre/lib/security/java.policy file.
* Add i386 Yum repository
* create a new Yum configuration file:
# gedit /etc/yum.repos.d/fedora-i386.repo
* copy these settings into the new configuration file:
name=Fedora $releasever - i386
name=Fedora $releasever - i386 - Updates
* Remove the default Firefox (64-bit) installation
# yum -y erase firefox.x86_64
* Install 32-bit Firefox
# yum -y install firefox.i386
# yum -y install libXtst.i386
Other how-tos state that you need to remove openjdk. However, other programs on Fedora 9, like Eclipse, need the default Java. You should not have to remove your default Java installation (java-1.6.0-openjdk java-1.0.6-openjdk-plugin) because you can use the alternatives command to select the version of Java you need (but you need to make sure you don't use the rpm version of Sun's Java install, because it changes the /usr/bin/java executable to not point to the "alternatives" command symbolic links ).
# mkdir /usr/java
# cd /usr/java
(the .bin file NOT the rpm.bin - because the rpm changes the /usr/bin/java executable to not point to the "alternatives" command symbolic links).
# chmod +x jre*
* for a particular user# cd /home/yourusername/.mozilla/plugins# ln-s /usr/java/jre-6u7-linux-i586/plugins/i386/ns7/libjavaplugin_oji.so* for all users:# cd /usr/lib/mozilla/plugins# ln-s /usr/java/jre-6u7-linux-i586/plugins/i386/ns7/libjavaplugin_oji.so- OR -
- Use alternatives command (for all users)(you can also use the alternatives command to set the plugin link - since FireFox is the only app that needs the Sun Java and it uses libjavaplugin.so rather than the libjavaplugin.so.x86_64 used by other programs (like Eclipse) on 64-bit Fedora 9).
# /usr/sbin/alternatives --install /usr/lib/mozilla/plugins/libjavaplugin.so libjavaplugin.so /usr/java/jdk1.6.0_07/jre/plugin/i386/ns7/usr/java/libjavaplugin.so 2
# /usr/sbin/alternatives --config libjavaplugin.so
There is 1 program which provide 'libjavaplugin.so'.
*+ 1 /usr/java/jre1.6.0_07/plugin/i386/ns7/libjavaplugin_oji.so
Enter to keep the current selection[+], or type selection number: 1
If you get something like the following message after installing firefox.i386:
Could not find compatible GRE between version 1.9b5 and 1.9b5.
Then you need to find your GRE version number by running this command:
# /usr/bin/xulrunner --gre-version
Then edit your firefox application.ini file as follows:
# gedit /usr/lib/firefox-3.0b5/application.ini
And change this:
to this (using the version GRE number from the xulrunner command executed above):
Might also have something to do with this file:
see this post: Conflicts has not been updated for ~b4 (firefox cannot start after xulrunner upgrade) where Linas says:
I found a fix for this. It was some sort of packaging problem, left over from earlier versions.
The directory /etc/gre.d (gecko rendering engine) contained a config file that specified
earlier (and inappropriate) xulrunner versions. I discovered this while performing a
dpkg -P xulrunner xulrunner-1.9 firefox firefox-3.0 (-P is purge-remove, which removes
the config files as well as the binaries/libraries). dpkg reported an error, complaining that
/etc/gre.d was not empty. Upon removing this directory, and reinstalling firefox-3, the
troublesome error message went away, and firefox started working.
I had to manually remove /etc/gre.d/1.9b4.system.conf -- it was this file that caused
all the problems for me.
Still no joy. I'm running fedora 9 x86_64, and java has never worked via firefox for me. So this post looked right on target.
I did all the steps, and they all worked as stated (including the GRE min/max vesion issue). But still java just doesn't work from firefox. Where do I look for the errors (logs etc). Other suggestions?
>But still java just doesn't work from firefox. Where do I look for the
>errors (logs etc).
Open your Java Control Panel (System>Preferences>Java). I had trouble with mine after a few Fedora updates, and can only get it to run properly by executing it from the command line with "usr/java/latest/bin/jcontrol".
Go to the Advanced tab, go to Java console, and select Show console, click Apply button. You may need to restart your browser.
When you go to a page with a Java applet (like the VoxForge Read page), the Java console should appear and should give you some hints on your problem.
I didn't get much info from the java console, and pretty much gave up on this. A day later I did a routine yum update (still have the 32 bit firefox and java installed and yum correctly only looked for 32 bit updates for those and did 64 for everything else), and now its working! I don't what update fixed it but now all is well!