Java crashes in Mozilla Firefox

Ian Malone ibmalone at
Thu Oct 6 20:42:11 UTC 2011

On 6 October 2011 13:10, Per Anton Rønning <pa-ronn at> wrote:
> Ian Malone wrote:
>> On 6 October 2011 09:26, Per Anton Rønning <pa-ronn at> wrote:
>>> Hi all,
>>> I downloaded the latest Firefox, and the latest Java as well. But now FF
>>>     crashes when trying to start Java Plugin. My internet banking logon
>>> application is a good example, but it also crashes when trying to check
>>> if Java is correctly installed form the Java homepage (Oracle).
>>> I Tried to go back to my previous Firefox (FF 3), but to no avail.
>>> Has any of you encountered this problem, and managed to find a fix?
>>> So far I am unsuccessful. I have browsed the net and found many
>>> references to this problem, but no clue to a fix. So I hope some of you
>>> guys may have something.
>> Hi,
>> I'll look up my settings for icedtea this evening if no-one else has
>> done it by then, libnpjp2 is the plugin for newer versions of firefox.
To correct myself slightly: libnpjp is what the new style plugin is
called in Sun/Oracle jre. The openjdk IcedTea plugin is called... and the link that alternatives maintains to point to
the selected java plugin is:

>> Information that would help:
>> 1. What version of Fedora you're running.
>> 2. What architecture you're on (x86/ x86_64), whether Firefox is 32bit, 64bit
>> 3. What version Java you're using and how it was installed.
>> 4. Whether you're using the 'alternatives' framework (you may have run
>> these commands if you installed a different Java from openjdk via
>> yum).
>> 5. How you 'downloaded the latest firefox': if your previous version
>> was FF3 then you're not on a current Fedora, which means I guess you
>> downloaded Firefox from the Mozilla website and untarred (? do they
>> offer it as an rpm?) it somewhere rather than through yum.
> Hi Ian
> 1. I run Fedora 9. But by browsing I have discovered the same problem
> pertains to  Fedora 13.
> 2. x86 (32 bit FF)
> 3. jre1.6.0_27 (rpm)
> 4. No altrernatives framework (at least not chosen by myself)
> 5. From the Firefox website, firefox-6.0.2.tar.bz2.

So the first thing is that the best way to get this working is to use
a new version of Fedora with java-1.6.0-openjdk, icedtea-web and
firefox installed via RPM.

That said if you want to try to knock your current system into shape:

I've got a jre1.6.0_13 rpm lying about (64bit, but not too different)
which contains /usr/java/jre1.6.0_13/lib/amd64/
You should be able to find your equivalent by doing:
rpm -ql jre|grep libnpjp2

One important thing is that the plugin firefox finds needs to be
located in the installed java directory, so you do not copy the plugin
to whatever your plugins directory is, you symlink it.

My firefox is centrally installed, fedora uses
/usr/lib/mozilla/plugins (also lib64 and plugins-wrapped variants) to
hold centrally installed plugins. You've untarred firefox somewhere
which means that any plugin your rpm or alternatives placed in that
central location is probably not picked up. So best guess is then that
you either want to:
ln -s MYlibnpjp2location myfirefoxlocation/plugins/
ln -s MYlibnpjp2location ~/.mozilla/plugins
The later will only affect your own account.

Other things that may be problems/offer clues (not really in order of
ease or simplicity):
0. Check about:plugins in Firefox shows the java plugin.

1. I'm surprised all of Firefox crashes, FF6 should be able to survive
plugin crashes, check your system meets the requirements for Firefox: (linux
requirements are at the bottom)

2. Check java actually works, not sure the best way to check this,
possibly find some jar file and see if it runs locally, either from or an application like ImageJ or JEdit (see Google)

3. Check the symlink you've created resolves to the actual java
location, e.g. I can do:
readlink -f /usr/lib64/mozilla/plugins/
and get
which is the lib location for openjdk.

4. See if
reports any 'not found' (n.b. use correct location of


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