How to use Java in Firefox

[trope]

I am trying to use an application in Firefox that requires Java and I'm wondering if I don't have it or it isn't installed properly. I also tried going to a java test page to tell me what version and nothing loads. I am using Linux Mint 14 (Nadia) and Firefox. I found the following command while browsing which should show versions of Java installed, but I don't know how to interpret the output.

update-java-alternatives -l

java-1.6.0-openjdk-amd64 1061 /usr/lib/jvm/java-1.6.0-openjdk-amd64
java-1.7.0-openjdk-amd64 1071 /usr/lib/jvm/java-1.7.0-openjdk-amd64
java-gcj-4.7 /usr/lib/jvm/java-gcj-4.7

What are the next steps to get it to work in my browser? Thanks!

[ajgreeny]

You need to install the icedtea-7-plugin for the browser, and I think you should probably need openjdk-7-jre as well, if you haven't got them.

[trope]

I followed all the instructions on this page:

http://community.linuxmint.com/tutorial/view/1091

and when I tried the "about:plugins" step it does list the icedtea plugin so I think it is installed. However the last step

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ln -s /opt/java/64/jre1.7.0_09/lib/amd64/libnpjp2.so ~/.mozilla/plugins/

did not work, I get the error message

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ln: failed to create symbolic link `/home/max/.mozilla/plugins/libnpjp2.so': Permission denied

I reopened firefox and the java test still does not work. The icedtea plugin is listed in the plugins section. Appreciate anything else I can try.

[trope]

The java test does not work in Chrome either (icedtea plugin installed), which leads me to believe that Java is not installed properly on my computer?

[palo]

Hi trope. It looks like things are a bit muddled with a mix of Oracle and Open java on your setup.

Firstly the disadvantage to installing Oracle java from the tutorial (aside from the possibility of making a mistake in any one of the many steps), is that you will manually have to install an updated version when it is released. I have the installer from a PPA for some time which has been hassle free and updates are done automatically. You can do this by following the instructions here.

Once that is done you can open Synaptic and search icedtea then completely remove any of that you have installed. Then check to see if your browsers are set to use the java. I keep mine off so I have to intentionally enable it to be used on a site. It is extra work but a good security step, and recommended.

Firefox - go to addons>plugins and find Java Plug-in 10.51.2 - the options are Always Activate, Never Activate and Ask to Activate(recommended). When set to Ask, going to the "check" site will still show a problem until you click in the box and follow the next dialogue to give it permission.

Chrome - In the address bar type about:plugins. Find java and see if it is set to Enable - if you do not check Always allowed you will be able to allow on a per use basis.

Also version check in a terminal should show this:

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 ~ $ java -version
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
Java HotSpot(TM) Server VM (build 24.51-b03, mixed mode)

Next comes LibreOffice - it needs to have java recognized to function properly. Open Writer - go to Tools>Options and click on Java giving it a few moments for discovery. You will likely see only the version you installed.

Hth
Pat

[trope]

Worked great, thanks! Also got to read about PPAs, was not familiar with them.