Your specific problem has many long threads in the forum and appears to be a problem created by Oracle/Java in their latest version 7 update 10 -- https://support.mozilla.org/en-US/search?q=Java+7+update+10&num_voted=0&num_votes=&asked_by=&answered_by=&q_tags=&created=2&created_date=12%2F01%2F2012&updated=0&updated_date=&sortby=0&a=1&w=2

Latest Java news
Java (apparently versions 4-7) have a serious security flaw that is being exploited to steal users personal and banking information and may have other serious security ramifications. Even Homeland Security has recommended that all users disable Java in their browsers. Apparently Microsoft has not gotten around to disabling Java like Mozilla/Firefox, Apple and others have done. See -

• http://blog.mozilla.org/security/2013/01/11/protecting-users-against-java-vulnerability/
• various links - https://encrypted.google.com/search?q=%22homeland+security+emergency+readiness+java%22&btnG=Search&hl=en&lr=&tbs=qdr%3Ay&gbv=1

Oracle have released update 11 for Java now which I have installed.Still no new version of the Java Platform appears in Firefox. Java will only work in Firefox if update version 9 of the platform is used in conjunction with latest version 11. I don't understand why updates from Oracle do not have new Java Platform especially if version 9 is dodgy.You need Java when using some websites so this problem needs fixing in Firefox!

Oracle screwed up a Registry Key entry in 7u10 and did the same in 7u11 - Firefox can't find the necessary Java Platform Next Generation plugin without that "Key".

Sorry you are having a problem with Java in Firefox, but Java is Oracle's product and it is up to them to fix it, but with the zero-day exploit in Java now that is a moot point.

See:

• http://kb.mozillazine.org/Java

Thanks for all the responses to my problem.I guessed the problem was with Oracle who supply Java.So registry key is missing which is why Java Platforms versions 10 and 11 do not work in Firefox.I note from the link given above by cor-el that the problem will be fixed in update 12 so will wait and see.Also it appears you can add the key to your registry although I am not clear from what I have read how this is achieved.I think I will leave tampering with the registry alone especially as you can mess things up if you do not know what you are doing.Shame a small program not issued by Oracle to add this key as many people appear inconvenienced by their faulty application!

According to this bug on the Oracle site http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8005410 , the problem occurs because their installer did not properly recognize prior Java versions and is compounded by a problem with systems having the JavaFX stand-alone application installed.

So, if you see JavaFX in your list of installed programs (Windows: Control Panel), remove it. It might also be best to remove all Java from your system before installing the new Java.

I would recommend JavaRa to uninstall all previous Java from your system, but, sadly, it has not been updated since October 2012 and does not include and will not find more recent versions of Java files and/or registry keys.

Oracle has released Java 7 update 11 to address the vulnerability recently recognized in Java 7 update 10 and some prior versions. Java 6 update 38 was not updated; support for the Java 6 versions ends in February 2013.