How To Run Java Applications On Systems Without JRE

Martin Brinkmann
May 20, 2012
Updated • May 20, 2012
Software, Windows

Great programs like the file hosting downloader JDownloader or the feed reader RSSOwl require Java to run. That's fine if you have full control of a system, and not so great if you sometimes have to work on a system where Java, in the form of the Java Runtime Environment (JRE) is not installed. If you want to take your apps with you, you need to find a way to get them to run on the system despite that.

The answer is jPortable, a portable Java Runtime Environment that is provided by Portable Apps. While designed for use with portable programs offered by the site and service, it is not restricted to that.

First thing you need to do is download the installer from the Portable Apps website. Please note that this is a web installer, which means that the installer will download files from the Internet during installation.The whole package has a size of roughly 38 Megabytes. The installation basically moves all files into a folder that you have selected before. This can be an USB drive or stick, or an internal hard drive for instance.

The portable version of Java is installed in \PortableApps\CommonFiles\Java by default, and recognized automatically by other programs of the Portable Apps suite. You can however use it as well for programs that are not part of the suite. Let me show you how you can get RSSOwl working with a portable version of Java.

Once you have installed both the portable Java version and RSSOwl, you need to copy the Java directory into the RSSOwl directory. Once it is there, rename the Java folder to jre, and start RSSOwl. You will notice that it will start up just fine, even with no Java installed on the system.

There is a second option available, which works if you can modify the system paths. Use the Windows-Pause shortcut to bring up the System control panel applet. Click on Advanced system settings there, and locate Environmental Variables in the window that opens up. (this is the way it is done under Windows 7)

Here you find user and system variables.  Find path under System, select it, and click on Edit to modify it. Simply append a ; followed by the full Java portable directory path to it, and click on ok afterwards to save the new setting. If you prefer a better editor interface, try Redmond Path instead.

You can also use the command line to start Java programs from there.

Having access to a portable version of Java can be quite useful in certain situations. You do however need to remember to update it regularly when a new version of Java gets released by Oracle, to avoid any kind of trouble with security issues or other issues that are fixed with updates. (The article is an update to the first review of Java Portable which we have published back in 2010)


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  1. Anonymous said on March 9, 2023 at 1:52 pm

    Does it come back after every “moment” update?

  2. Baloney said on March 9, 2023 at 2:23 pm

    Yeah right.. Like this is going to stop defender from running =) This is comedy gold right here.

  3. Anonymous said on March 9, 2023 at 3:25 pm

    no ‘about the author’ paragraph?

  4. Gregory said on March 9, 2023 at 4:19 pm

    For permanent disable defender is if removed complete from system no just change permission folder.

    Just this is joke.

  5. moi said on March 9, 2023 at 5:57 pm

    simpler, load Autoruns (SysInternals)
    – filter “Defender”
    – untag all entries
    – reboot
    nothing has changed since my 1st modification years ago

  6. John G. said on March 9, 2023 at 6:32 pm

    I wouldn’t disable Defender imho, it has too many hidden roots inside Windows itself. One time I tried to uninstall it using brute force scripts and then the Onedrive feature stopped working definitely. A reinstallation was needed and since those times I prefer to maintain Defender untouched. It’s a better method to install another antivirus and it will disable Defender in a safer and easier mode (e.g., Avast is the best in this way, and also Panda Cloud Free is good too).

  7. boris said on March 10, 2023 at 12:19 am

    You can not stop defender from running in background or remove it without some penalty. All you can do is to limit telemetry.

    1. TelV said on March 10, 2023 at 4:52 pm


      It’s probably Smartscreen which is preventing WD from being disabled. Get rid of that and the problem should be solved:

  8. hoho said on March 10, 2023 at 1:47 pm

    Remove Windows and go for Linux.

    1. basingstoke said on March 10, 2023 at 2:51 pm

      Linux sucks dude. Besides it’s not comparable to Windows, these OSes are in different classes entirely.

      1. Derp said on March 10, 2023 at 4:36 pm

        I use Linux as my daily driver. It’s far more stable than Windows. When’s the last time you used Linux, 2010?

      2. Bromosexual said on March 11, 2023 at 2:04 am


        You’re right, dude. Bro, linux is just a bunch of code that starts before the OS, dude. Brobrodude, that shit ain’t even got emojis, dudebrodudeman! Dudebro, it’s no way near as cool as Windows with its hardcoded abilities to make money off the user, bro. Yo brodude man, you’re the coolest dude ever man, bro. Dude.

      3. basingstoke said on August 16, 2023 at 7:20 pm

        Lol what? Windows 7 doesn’t come with any Emojis

  9. TelV said on March 10, 2023 at 4:46 pm

    Download Autoruns and remove the checkmark from Windows Defender. It doesn’t remove it, but it will never run.

  10. Simon said on March 10, 2023 at 8:37 pm

    Just use “Defender Control”:

    Per this video,
    it also works on Windows 11 too…

  11. Someone said on March 10, 2023 at 9:26 pm

    Win Defender, is completly the most succesful free-built in antivirus of Microsoft. Really nice product. Saved my ass a lot of times. Has updated malware database, completly strong defence
    from whatever smart screen disables. Or if you want better and more upgrated (paid) program,
    you can go further. But defender is always on your side.

  12. CalixtoWVR1 said on March 10, 2023 at 10:03 pm

    Why would one disable Windows (or Microsoft) Defender in the first place?. I consider this to be playing with fire big time. Everybody knows that if one is using another A-V, Defender will be disabled on its own and won’t be in one’s way.

  13. Ed D said on March 10, 2023 at 11:09 pm

    Why would I want to disable Windows Defender in the first place? It’s a great anti virus in my opinion. Been using it since Windows 8 and and never had a problem or a virus. Why mess with a good thing, if it ain’t broke don’t fix it.

  14. owl said on August 17, 2023 at 1:57 am

    How a ridiculous article!
    I am thoroughly stunned.

    Why Should You Disable First-Party Windows Defender?
    I can only think that it is “malice or perversely intention (want you to buy a third-party AV where you can expect a back margin)” to guide invalidation without showing the premise.
    No sane company will use third-party closed source programs (such as AV).

    As I thought, “Ghacks Technology News” seems to be coming to downfall.

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