Gentoo Wiki




This guide explains how to install Java plugins so that they will work with the Mozilla Firefox browser.

Install Required Software

Mozilla Firefox

Install Mozilla Firefox with the java USE flag. You can check to see if it is enabled using app-portage/eix.

eix firefox

If the java USE flag is not enabled, you can enable it by adding it in the /etc/portage/package.use

echo "www-client/mozilla-firefox java" >> /etc/portage/package.use

or to the global USE flag file, /etc/make.conf.

In both cases, recompile firefox using:

emerge -avN mozilla-firefox


There are a couple of different Java Virtual Machines (JVM) that can be installed in Gentoo. For the purpose of this Wiki, you'll be given the option to install Sun's JVM or Blackdown Java. Either way, you will need the nsplugin USE flag, either on the command line or in your make.conf.

Note: browserplugin and mozilla USE flags are obsolete. So, please don't use them.


Note: This is not for AMD64 installations. Use Blackdown instead. Or, check AMD64 tech-notes or HOWTO AMD64 if you must use sun-jre

The Java Runtime Environment, which comes directly from Sun Microsystems can be retreived by doing:

echo "dev-java/sun-jre-bin nsplugin" >> /etc/portage/package.use
emerge -av sun-jre-bin

or if you will be using the SDK:

echo "dev-java/sun-jdk nsplugin" >> /etc/portage/package.use
emerge -av sun-jdk
Note: Because of licensing issues with Sun JRE/JDK v1.4, emerge will tell you to download the JRE/JDK from a specific web site and ask you to place that file into /usr/portage/distfiles. From there, you would need to re-run emerge again to continue installation.
Note: You may need glibc-2.3.5 for Sun JRE/JDK as this dependence may not be in Portage.

Blackdown JRE

Warning: Blackdown-jre's (As well as jdk) nsplugin Use flag has been masked. This means that you can not use java (Blackdown version) in your browser (Firefox). For more info, look here

The Blackdown JRE is a Sun related version of Java that is also available for non-PC platforms and it does not require a license acceptance like the Sun's version does. However, some people say that it is slower than Sun's version of the JVM. To install Blackdown JRE on your system, type the following command

echo "dev-java/blackdown-jre nsplugin" >> /etc/portage/package.use
emerge blackdown-jre

Setup Firefox With Java

First, you must make sure Java is enabled in Firefox. Do this by opening Firefox and going to Edit ยป Preferences and then opening up the Web Features or the Content section. Make sure that the Enable Java option is checked.

The Gentoo way

The new dev-java/java-config in portage introduces a cleaner way of configuring things related to Java. As root, run to see your type and version:

# eselect java-nsplugin list
Available Java browser plugins
 [1]   sun-jdk-1.5 
 [2]   sun-jdk-1.6  current
# eselect java-nsplugin set plug-in

Replacing plug-in with the appropriate item listed in the first command.

Symlinking Java to Firefox

If Java still does not work with Firefox, you must make a symlink to the Java plugin so that Firefox can recognize it. First, you must locate the Java plugin by searching your system.

Finding the plugin

With slocate

If you have emerged sys-apps/slocate, then do the following:

# updatedb
# locate

Use the path that was returned by locate and link the plugin to Firefox in one of two ways mentioned in the symlinking section below.

With find

This method may take a little bit longer than slocate, but won't require a database update. To use this method sys-apps/findutils is required, which is standard in Gentoo Linux. Multiple hits may be found; you may have to try the next step a couple times with different paths until you find one that works.

find /opt -name javaplugin_oji\*

If this method does not find the sun plugin; try

find /opt -name "*javaplugin_oji*"

Symlinking the plugin

Link current user

This method will only allow the current user to use the Java plugin.

ln -s <path-to-java-plugin> ~/.mozilla/plugins
Note: You will need to make sure you link with the correct plugin for your version of GCC. To find out your current version of gcc execute: gcc -v. For instance at the time of writing gcc-3.4.3 is what came with my Gentoo. From the IBM java vm, the correct library to link is /opt/ibm-jre-bin-1.4.2/bin/ and NOT the one described here. This may applies to other VMs too.
Link Globally

If you have a system with multiple users, or you want the plugin available to any users that may exist in the future, you have to link it globally. To do this, run the following commands:

# ln -s <path-to-java-plugin> /opt/netscape/plugins/

To get the benefit of any update to the system VM, you need to use the VM specified by the java-config-2 command since there is a symlink to the current VM in /etc/java-config-2/. Therefore, issue the following command:

# ln -s /etc/java-config-2/current-system-vm/jre/plugin/i386/ns7/ /opt/netscape/plugins/

If you are using Sun JDK 1.6 with Firefox, you can do the following:

# ln -s /opt/sun-jdk- /usr/lib/mozilla-firefox/plugins/


Xlib.lock failed

If firefox found java (type about:plugins in adress line) and java still doesn't work. Try to start it from a terminal. Errors like "java_vm: xcb_xlib.c:50: xcb_xlib_unlock: Assertion `c->xlib.lock' failed." you can fix with instructing portage to disable assertions in libxcb. To achieve this, create the file /etc/portage/env/x11-libs/libxcb with following content:


and run emerge -av libxcb.

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Last modified: Sat, 23 Aug 2008 12:23:00 +0000 Hits: 125,397