You can access Add-ons through the 'tools' drop down menu, or through the icon with three horizontal lines. Select 'Add-ons', this should open the Add-ons manager. Select 'Plugins' from the left side of the manager, you should now see a list of the plugins currently installed in your Firefox browser. Confirm that your Java platform is set to either 'ask to activate' or 'always activate'.
If you are still having issues with Java content, you may need to update your Java components. This support page can walk you through updating and managing your Java plugin:
You can try these steps in case of issues with web pages:
You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.
- Hold down the Shift key and left-click the Reload button
- Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
- Press "Command + Shift + R" (Mac)
Clear the cache and remove cookies only from websites that cause problems.
"Clear the Cache":
- Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"
"Remove Cookies" from sites causing problems:
- Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies"
Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.
- Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
- Do NOT click the Reset button on the Safe Mode start window