I'd like to install Java in Firefox on Windows but I don't have administrative privileges on my machine.

Any clue on how to achieve this?


Unfortunately the answer for the moment is negative:

You can't install Java in a portable manner, since it requires lots of updates to the registry.

There is nowadays much of a debate as regarding that point, and doubtless with all the portable apps hype going on it's only a matter of time before a portable version of Java becomes available that doesn't use the registry.

To resume, while Firefox is portable, Java isn't. Not yet, anyway. Stay tuned to Sun announcements concerning Java, and hopefully the problem will be resolved in the coming months.

  • @fabianvilers: Thanks for choosing my answer. As regarding a possible work-around, if you have Virtual PC installed on the machine, nothing prevents you from creating a virtual machine where you're the administrator. – harrymc Jan 6 '10 at 10:20

Browse to http://portableapps.com/apps/internet/firefox_portable and download Mozilla Firefox, Portable Edition. Install it to a local folder with write access. You can add anything as this version puts all the files in one location.

You can also install a portable java on a usb stick, check this.


  • I already did, Firefox is installed in a writeable directory but: - the online installation of Java fails because I'm behing a proxy - the offline installation of Java fails because I don't have admin privileges :-( – Fabian Dec 17 '09 at 9:22
  • I have edited my answer – Chris Dec 17 '09 at 9:39
  • Interresting! But how will Firefox know about Java on my USB stick? – Fabian Dec 17 '09 at 13:07
  • When u use a portable OS something like MojoPack manufactured by RingCube, you can use it almost everywhere. Assuming you will use a portable OS. – Chris Dec 17 '09 at 13:58
  • Well, Java's installed on my flash usb, how can I told Firefox to use it? – Fabian Jan 4 '10 at 10:30

Not much detail in this question but this part confused me:

I don't have administrative privileges on my machine.

It's your machine, yet you have no administrative privileges? Did you forget the password? You can clear the administrator password using Offline NT Password & Registry Editor. If it is someone elses machine, you can download the Java installer and extract it with Universal Extractor Binary Archive (no install needed) to any location you want, then follow the steps Goyuix outlined to have Firefox recognize it.

Maybe more insight into why you don't have administrative privileges can help us give you a better answer.

  • I mean the machine on witch I'm working... – Fabian Jan 5 '10 at 10:38

If you have Firefox and Java running on that computer (portable or otherwise), the only remaining glue is to get the Java Platform Plugin registered with Firefox. How it detects where Java is installed and which runtime to use is a bit of a mystery honestly, it probably looks in the registry or checks for the JAVAHOME environment variable. Not sure.

  • Copy the np*.dll files for your version of the JRE from the following location: C:\Program Files\Java\j2re\bin\ (or whatever the path is to your JVM)
  • Paste them into your Firefox plugins folder, which is typically in the following location: C:\Program Files\Mozilla Firefox\plugins (or whatever the path is to your Firefox)

There are also several references to Java in the extensions.ini, extensions.rdf and pluginreg.dat. All of these are plain text files that you can edit, though it still may not be the required ingredients. Compare them with a known good, working Firefox + Java install and hopefully you can make it work. These files are in the %APPDATA%\Mozilla folder, and in your profile, by default. Not sure where they will be on your portable version.

  • Tried but it seems still doesn't work, even with a JAVAHOME environement variable set up. :-( – Fabian Jan 5 '10 at 11:30
  • I don't have a JAVAHOME defined and it works, so clearly that isn't the secret glue to hook them together. I poked around the registry and there doesn't seem to be anything useful there. Maybe this is a topic better suited to the Mozilla forums? forums.mozillazine.org – Goyuix Jan 5 '10 at 15:49

Firefox (both installed version and portable version) may use the environment variable "MOZ_PLUGIN_PATH" to search for plugins, so you can: 1) create a new environment variable in your OS using the above-mentioned name and put as value [current plugins folder];[portable java plugins folder] 2) simply create a batch file (.BAT file), using the "set" DOS command to set the above-mentioned environment variable in the same format: set moz_plugin_path=[current plugins folder];[portable java plugins folder] and then insert a new line to run Firefox. 3) using the .INI file of the portable firefox version to include the plugins folder of Portable Java.

The [current plugins folder] is the current folder of Firefox Plugins. If you don't know where it is, open firefox, go to Plugins page, search for "default plugin", you can read the full path where the default firefox plugin is placed. The [portable java plugins folder] is the current folder of plugins used by portable java. It is placed in "Java\bin\new_plugin" folder (Java is the root folder where Portable Java has been installed). If you still have problem, search for file "npjp2.dll", and take note of the related folder where it is placed.

To check if one of the above-mentioned procedure has gone well, open Firefox and you should have two new items inside Plugins page: "Java Deployment Toolkit" and "Java Platform SE".

Hope this may be useful for all of you.

P.S. If you use the procedure 1, you must logoff Windows and logon Windows again in order to let Windows load the new environment variable.


Sure, gain Admin priviledges ;)

Use OphCrack to get the passwords for the local accounts on your computer and then use the credentials to launch an offline Java installation as an admin. Of course, this is assuming the rainbow tables in Ophcrack are capable of cracking the local account passwords.

  • this.....is a horrible idea. But I like it just because of how outside the box it is. Be warned: being caught doing this will get you in heaps of trouble. – Babu Dec 31 '09 at 17:29
  • If this is at work it's a quick way to get disciplined/terminated. – MDMarra Jan 1 '10 at 1:29
  • I hope you're kidding. – krhainos Jan 6 '10 at 7:51
  • Not sure why the negative comments about my solution. Just because it's not ideal does not mean it's a viable alternative. – rodey Jan 6 '10 at 14:28


Easy peasy......even mom can do it! ;-)

  • 1
    Thanks but by now I've leaved the customer where I had no admin privileges. – Fabian Jun 25 '10 at 12:48

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