Apparently, I have OpenJDK 6 JRE (openjdk-6-jre 6b27-1.12.6-1ubuntu0.12.04.2) and 7 JRE (openjdk-7-jre 7u25-2.3.10-1ubuntu0.12.04.2) installed in parallel – I don't know why I have both of them, I can't remember installing any of them manually.

However, the Firefox Java plugin is occasionally reported to be out of date by some websites, and it seems to me that it relies on JRE 6. How can I make Firefox use the newer version? Removing JRE 6 seems like a bad idea; when I attempted to do so in synaptic it appeared to me that a lot of software still relies on the older JRE, since removing it would have removed programs like jedit as well.

Do I mix up stuff? I'm not even sure how the FF plugin interferes with the OpenJDK JRE's.


Having tried even more, the problem persists. Using update-alternatives --config java, I see that the default Java version (with status "manual mode") is already set to Java 7, and java -version returns "1.7.0_25". The file /usr/lib/jvm/java-7-openjdk-i386/jre/lib/i386/IcedTeaPlugin.so exists, but still Firefox shows the Java 6 plugin when looking at about:plugins.

To sum it up:

How do I make Firefox use the IcedTea plugin belonging to the default Java version?


4 Answers 4


Install the version 7 of the icedtea plugin either from the software center or using command line:

Open a terminal by pressing Ctrl+Alt+T and enter:

sudo apt-get install icedtea-7-plugin

Remove the older icedtea:

sudo apt-get remove icedtea-6-plugin

Then restart Firefox and type about:plugins to check the version of java plugin. Or go to java website to check the version as well as if it is working properly.

Hope this helps

  • 1
    The IcedTea-7 plugin is already there, as I pointed out in my question.
    – lenz
    Oct 1, 2013 at 16:33
  • 1
    May be removing icedtea-6 will help.
    – user68186
    Oct 1, 2013 at 17:15
  • 2
    Thanks, it actually did solve the problem. While removing JRE 6 was not an option (I had considered that), removing only the plugin was the thing to do. I marked your revised answer as accepted, although your original post was not very helpful, given the information in my question. @Thomas W. was first to bring up the solution, but since he only posted a comment and no answer, I can't reward him the bounty.
    – lenz
    Oct 3, 2013 at 22:10

Most of those websites are using javascript to check what version of Java your browser is running and since it does not match the Oracle Java version they complain that you need to update Java in your system. I would ignore any of those messages if the Java applets are working properly.

To check what version of Java Firefox is running just type on the location bar (address bar) about:plugins, it should display all the plugins Firefox is using.

I bet Firefox is using the latest JRE and the websites are just complaining that it is not the same version as Oracle is. Keep your system updated and ignore that.

  • Thanks, I forgot to mention that I did that: the IcedTea plugin used (that's what it is all about, isn't it?) is /usr/lib/jvm/java-6-openjdk-i386/jre/lib/i386/IcedTeaPlugin.so, so I guess this is not the newest... I couldn't find out how to change it though.
    – lenz
    Sep 17, 2013 at 11:09
  • sudo update-alternatives --config java should allow you to set the default Java version, no matter which are installed, you can test it then with java --version and icedtea will use the one specified by the first command, no matter of how many Javas you actually install. Sep 17, 2013 at 11:20

If you're using Fedora you need to install

sudo yum install icedtea-web

Restart your browser after this.


You likely need to install the relevant plugin package to go with your java version:

sudo apt-get install icedtea-7-plugin

This plugin works with the main browsers: Firefox, Chromium, Google Chrome, and Epiphany. You'll need to restart your browser for the plugin change to take effect.

More information:



  • thanks, but dpkg -s icedtea-7-plugin gives me "Status: install ok installed", so that's not what I need, I guess.
    – lenz
    Oct 1, 2013 at 16:50
  • 2
    The latest "version" of the software is whatever's in the repositories, what makes you think there's a later version of the plugin, @lenz? Did you try removing icedtea-6-plugin ?
    – Thomas Ward
    Oct 1, 2013 at 17:03
  • Thanks a lot @Thomas W., removing the icedtea-6-plugin did the trick (without removing Java 6 completely, which I still need). Why don't you put this in an answer, so I can reward you the credit?
    – lenz
    Oct 1, 2013 at 21:16

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