Last updated: January 25, 2019
Update: Firefox support for the Java NPAPI plugin ended with Firefox 52. If you run Windows 10 and need to view Java content, please see the Java support on Windows 10 article instead for more information. macOS users, please see Java support in Safari 12.
Firefox is a free web browser application developed by the Mozilla Foundation. It runs on desktops with the Windows, Mac OS X and Linux operating systems. A mobile version of Firefox is available for Android devices. A mobile version of Firefox will also be available soon for iOS devices.
Java is a free software developed by Oracle Corporation, and also a programming language. When you download and install the free Java software, you are installing the Java Runtime Environment (JRE), including the Java Virtual Machine (JVM). When referring to “Java” in this article, we are referring to JRE, a web browser plug-in required to load Java content in Firefox.
The following information pertains only to the 32-bit version of Firefox. Firefox 64-bit does not support Java. The very first step in resolving Java-related issues with your computer is to make sure your Java installation is current.
Enable Java in Firefox
If Java content does not load in a Firefox browser window, it may be that Java is disabled in Firefox’s Add-ons Manager. To check, click Tools in the Menu Bar at the top of a Firefox window, and click Add-ons from the drop-down menu (alternatively, type the keyboard command CTRL+SHIFT+A, or type about:addons in the browser’s address bar).
If your Menu Bar is not visible, click the Menu Button and choose Add-ons.
The Add-ons Manager will open in a new tab or window. In the left navigation, click Plugins. An alphabetical list of all currently installed plugins will display. Scroll down the list to find Java(TM) Platform SE in the list.
If you see (disabled) display for Java, it means that Java content will not display in Firefox. To display Java content, you must enable Java. To do so, click the Never Activate pull-down menu.
Select Ask to Activate if you want Firefox to ask you to activate Java each time you encounter Java content. Select Always Activate if you always want Java to activate without being asked. Your selection saves automatically, and (disabled) no longer displays.
Reload the Firefox window that contains Java content, and the Java content can now display.
Disable Java in Firefox
To disable Java in Firefox, open the Firefox Add-ons Manager following the instructions above. In the left navigation, click Plugins. An alphabetical list of all currently installed plugins will display. Next, scroll down the list to find Java(TM) Platform SE in the list. Click the Ask to Activate (or Always Activate) pull-down menu. Select Never Activate if you never want to use the Java add-on with Firefox. Your selection saves automatically.
To download the latest version of Firefox for free, visit the Firefox web site. Thank you for visiting Tech Help Knowledgebase to learn how to enable and disable Java in Firefox.