To Remove Java Deployment Toolkit you need go to your Control Painel and unistall it. Some sites need Java Plugin to play some games or functions and others, and always you need to download it do this from Oficial Site, in this case Oracle site.

• https://www.java.com

My plugins tell me I need to update Java because it is vulnerable, which one do I need?

You can find the latest 32 bit Java versions for Firefox on the Oracle website.

See Java Platform > Java SE 7u67/8u20 (JRE Download;32 bit for Windows)

• http://www.oracle.com/technetwork/java/javase/downloads/index.html
• http://www.oracle.com/technetwork/java/javase/downloads/jre8-downloads-2133155.html

Firefox states that The Java Deployment Toolkit plugin isn't unnecessary in most cases & users should keep it disabled unless strictly necessary. That's correct. The Java Deployment Toolkit (Java DT) plugin is superfluous for regular people and can be safely "deleted" without loss of general Java browser functionality using these instructions from mozillazine: http://forums.mozillazine.org/viewtopic.php?f=38&t=2877359

Firefox also states the plugin will be automatically disabled and no longer usable, yet it still shows up on my add-ons manager list. There's a history of security drama between Mozilla and Oracle. If you'd like to get rid of these plugins permanently and not even allow Java to run in the browser and end up in a "safer" computing environment, you can do so following the guide linked above, starting at "My recommendation:"...

Do I really need The Java Deployment Toolkit 7.0.600.19 Plugin? Not unless you're a network admin familiar with IBM's HMC and need Firefox due to software restrictions. Or you're "rich internet application" Java developer who's testing out new code on remote machines. If you're neither of those cases, you can safely delete the Java DT plugin without losing "general Java functionality" in the browser.

How can I remove The Java Deployment Toolkit 7.0.600.19 Plugin? Do I need to download Java 8 from the Oracle website? I'd actually recommend Java 8 over previous versions because for me at least there is a performance gain in some of the (non-browser) applications I use, even over v7. Oracle also claims it's a more secure version as well. Just be sure to uninstall previous Java installations before installing v8. However, in regards to the Java DT plugin, you can delete it anytime following instructions from the above link.

msgins: My plugins tell me I need to update Java because it is vulnerable, which one do I need? Mozilla's plugin checker does a good job if it detects the standard Java plugin (Java(TM) Platform SE) is out of date or not. If it detects that plugin is out of date then going to Java.com and updating right there will "do the trick." You may want to consider going with Java v8 though, even though it's not the default option given on Java.com (due to its still "relatively" new status, although it's been out since March 2014) I've personally found performance increases over v7. v8 is scheduled to be the default option on Java.com in March 2015. If you decide on going with v8, you'd better uninstall all of the previous Java versions in the control panel->programs & features first.

Also, user "Diego Victor" is incorrect in his answer about the Java DT plugin. The Java DT plugin is not listed in the installed programs in the control panel. I believe he is confusing the Java DT plugin with the standard Java plugin known as "Java(TM) Platform SE" that's required for Java content functionality in the browser.