Use the Java plugin to view interactive content on websites

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Important: Firefox has stopped some versions of the Java plugin from running automatically because of security issues. However, you can still use Java on trusted sites if necessary. Learn how.

Many web pages use Java applets for interactive content such as online games. Before Firefox can run Java applets you must have the Java plugin properly installed and enabled. Java is a programming language that can run on Windows, Mac, Linux, and other computer systems. This article will help you install or update Java and get it working in Firefox.

  • Java is not the same thing as JavaScript (see this article for information about JavaScript).

Installing or updating Java

Manual install or update

  1. Go to the download page at java.com.
  2. Click the Free Java Download button.
  3. Click the Agree and Start Free Download button to download the Java installer to your computer.
  4. After the download is complete, close Firefox.
  5. Open the file you downloaded to start the Java installation.

Automatic update

Java for Windows includes a Java Update feature that periodically checks for updates and notifies you when an update is available for installation.

Note: To eliminate potential security vulnerabilities and to save disk space, you should remove any older Java versions that may still be installed. For more information, visit How do I uninstall Java on my Windows computer ? on java.com.

On Mac OS X 10.6 and below, Java is installed with the operating system. To update Java, use the Mac OS X Software Update feature.

On Mac OS X 10.7 and above, Java is not installed by default. To install the latest version of Java, go to the download page at java.com. See How do I install Java for my Mac? for system requirements and installation instructions.

See Java Plugin Install for Linux at oracle.com for help installing or updating Java on your Linux system.

Testing Java

A number of online tools will tell you if Java is installed and enabled in Firefox.

Enabling Java

If Java is not working, make sure that the Java plugin is enabled in the Add-ons Manager tab:

  1. At the top of the Firefox window, click on the Firefox buttonOn the menu bar, click on the Tools menuAt the top of the Firefox window, click on the Tools menu, and then click Add-ons. The Add-ons Manager tab will open. Click the menu button New Fx Menu and choose Add-ons. The Add-ons Manager tab will open.

  2. In the Add-ons Manager tab, select the Plugins panel.
  3. Click on the Java (TM) Platform pluginJava Plug-in 2 for NPAPI Browsers (Mac OS 10.5 & 10.6) or Java Applet Plug-in (Mac OS 10.7 and above)Java plugin to select it.
  4. Click on the Enable button (if the button says Disable, Java is already enabled).
  1. At the top of the Firefox window, click on the Firefox buttonOn the menu bar, click on the Tools menuAt the top of the Firefox window, click on the Tools menu, and then click Add-ons. The Add-ons Manager tab will open. Click the menu button New Fx Menu and choose Add-ons. The Add-ons Manager tab will open.

  2. In the Add-ons Manager tab, select the Plugins panel.
  3. Click on the Java (TM) Platform pluginJava Applet Plug-inJava plugin to select it.
  4. Select Always Activate in its drop-down menu if it's not already set.
Note: You only need to enable the "Java(TM) Platform" plugin, if it is disabled. The "Java Deployment Toolkit" plugin is used by Java developers to detect your Java version and to deploy their Java applications and does not need to be enabled for Java to work.

Troubleshooting

After enabling Java in your operating system and through your Firefox options, Java may still fail to work properly. To activate Java, try the following:

Uninstall JavaFX if installed

In some cases, after updating from an earlier Java version to Java 7 Update 10 or above, the Java (TM) Platform plugin is no longer detected. This can be caused by a conflict with Java and a standalone installation of JavaFX that prevents the Java plugin from being properly registered. To resolve the problem, uninstall JavaFX. For more information, see this java.com help page.

Remove outdated Java plugin files from the Firefox plugins folder

You may have copied Java plugins to the Firefox plugins folder in the past. Java plugin files from older versions in the Firefox plugins folder can prevent Java from working.

  1. At the top of the Firefox window, click on the Firefox buttonOn the menu bar, click on the Tools menuAt the top of the Firefox window, click on the Tools menu, and then click Add-ons. The Add-ons Manager tab will open. Click the menu button New Fx Menu and choose Add-ons. The Add-ons Manager tab will open.

  2. In the Add-ons Manager tab, select the Plugins panel.
  3. Select the Java(TM) Platform plugin and make sure that it is enabled.
  4. Check if the Java(TM) Platform plugin is correctly detected. For example, if Java 7 Update 45 is currently installed, the Java plugin in the Add-ons Manager tab should be listed as Java(TM) Platform SE 7 U45.
  5. If you find Java plugin files listed that do not match your current Java version, you may have outdated Java plugin files in the Firefox plugins folder which should be removed.

The Firefox plugins folder, if it exists, is typically in the following location:
C:\Program Files\Mozilla Firefox\plugins on 32-bit Windows, C:\Program Files (x86)\Mozilla Firefox\plugins on 64-bit Windows

Other software that may block Java

Even if Java is installed and enabled in Firefox, it may be blocked by other software or Firefox add-ons, such as the following:

  • The ZoneAlarm Pro software firewall can block Java. For more information on enabling Java through this program, see the ZoneAlarm Pro forum.
  • The NoScript extension for Firefox will block Java. For more information, see the NoScript FAQ.

Additional resources

  • The Java FAQs page at java.com answers some frequently asked questions.




Based on information from Java (mozillaZine KB)