How to turn off Java applets (Java Plug-in)
[Windows] Java Plug-in
By default, Firefox allows Java applets to launch automatically. However, you may decide that you do not want Java applets to run. To disable Java applets in Firefox:
- At the top of the Firefox window, click on the Tools menu, and then click Add-ons. The Add-ons Manager tab will open.
- In the Add-ons Manager tab, select the Plugins panel.
- Click on the Java plugin to select it.
- Click on the Disable button (if the button says Enable, Java is already disabled).
Java applets will no longer be permitted to launch in Firefox.
[Linux] Java Plug-in
IcedTea-Web Plugin executes Java applets.