Installing Java-got it to work, but don't understand

[Vic]

I've been trying to install Java, or more specifically, get the Java plugin to work with Firefox, for two days. I FINALLY got it working, but I am now even more confused.

To begin at the beginning:

1. Downloaded Linux Mint iso, installed it on PC.
2. Downloaded Firefox 2.0.0.5 into /home/Vic/firefox
3. Pointed desktop shortcut for Firefox to /home/Vic/firefox/firefox (shortcut works fine)
4. Installed Flash via Synaptic. Flash works fine.
5. Tried installing Java via synaptic. It completed, but about:plugins never showed Java (only Flash and Default Plugin).
6. Uninstalled Java via Synaptic and tried re-installing via Synaptic. Same result as #5.
7. Uninstalled Java via Synaptic and downloaded Java self-extracting file from Java site.
8. The installation instructions say to create a symbolic link in the Mozilla install directory. This is where I was going wrong. The instructions say the directory where the symlink goes is /usr/lib/mozilla/plugins. That directory exists, and has some working symlinks and some BROKEN symlinks in it, but pointing the symlink there does not work.

9. I noticed a directory /usr/lib/mozilla-firefox/plugins, but putting the symlink here also does not work. but, this directory also has some working and some broken symlinks in it.

10. It FINALLY occurred to me that I didn't install Firefox in either of these directories. I put it in /home/Vic/firefox. So, these two commands did the trick:

cd /home/Vic/firefox/plugins
sudo ln -s /usr/java/jre1.6.0_02/plugin/i386/ns7/libjavaplugin_oji.so

Now, Firefox's Java plugin works, but I am confused about some issues.

1. I assume that the directories /usr/lib/mozilla and usr/lib/mozilla-firefox are from the default distro install, and when I did a manual upgrade to Firefox 2.0.0.5, I should (or at least COULD have) have put the Firefox files in one of these directories. Which one would have been the appropriate one?

2. Flash installed perfectly. How? I didn't point the install to any certain directory (Synaptic did it all). I tried looking in the /plugins directory under all the various Mozilla and/or Firefox directories, but all the files that are symlinks have the red X on them. Yet, Flash still works. in /usr/lib/mozilla/plugins and in /usr/lib/mozilla-firefox/plugins and also in /home/Vic/firefox/plugins all the symlinks that have the word "flash" in them also have a red X on them. How is the Flash plugin working, then? I looked at this when it occurred to me that maybe I'm putting the Java symlink in the wrong place, and since the Flash plugin was working, all I had to do was find the Flash symlink, then put the Java symlink in the same plugins directory. But, no working Flash symlink is in any plugins directory I can find.

I apologize for the log-winded post, and for being a n00b, but I'm just trying to learn.

[scorp123]

Downloaded Firefox 2.0.0.5 into /home/Vic/firefox

Why? As you see it just causes troubles and confusion to have software installed outside of the packet managers. I mean ... It's OK if you know what you do. But if you don't it will be a rather frustrating experience. With your level of knowledge you'd be better off to only use software that is in the repos. At least for now.

[Vic]

I put it in my home folder because I did not know where it was supposed to go.

Is it /usr/lib/mozilla or is it /usr/lib/mozilla-firefox, or somewhere else?

The instructions page I referenced for installing the current version of Firefox specified /home.

I couldn't use the package managers because the current version of Firefox is not on them, not that I could find anyway.

I understand your "with your level of knowledge" comment, but this is precisely the issue I'm trying to learn about.

[scorp123]

I couldn't use the package managers because the current version of Firefox is not on them

And so? It will be there as soon as the people making the packages are done with finishing the package, doing their final tests, and so on. There is no need to hurry with upgrading "or else ...." .... This isn't Windows

I understand your "with your level of knowledge" comment, but this is precisely the issue I'm trying to learn about.

Don't get me wrong ... it's just that if you take on a too big of a challenge you might soon be frustrated. One step after the other.

/usr/lib/

/usr/lib is for libraries (in Windows you'd call that *.DLL's ...) and some software packages create their sub-directories in there. So by that logic /usr/lib/mozilla would be the libraries owned and used by the (classic) Mozilla web-suite which emerged out of the ancient Netscape Communicator browser suite -- often plugins will install into that location (/usr/lib/mozilla) because many other browsers that can use Mozilla's plugins will search for suitable plugins in that directory. Typical candidates: Opera and Konqueror. So /usr/lib/mozilla is there for compatibility purposes. And /usr/lib/mozilla-firefox would be the libs owned by the Firefox stand-alone web browser which emerged out of the Mozilla web suite. I think you already have one version of Firefox installed on your system and that's why those directories are there.

I saw in your other posting that you manipulated some of that stuff e.g. via symbolic links. I'd be cautious with that. Chances are that a future update will manipulate those things again and then things might all of a sudden stop to work.

Piece of advice: Either stick with the package manager and let it handle the software installations. It's not necessary to always and immediately have the absolutely newest browser release ... it will be in the repos when it's ready. Patience is your friend. If you nontheless want to have software installed that lives outside of the package manager (= the package manager has no knowledge and no control over it) then please really make sure that all the stuff installed via the package manager doesn't collide with the stuff you installed manually and vice versa --- stuff installed manually should not mess with things that were installed via the package manager.

So if you install a new browser into your /home directory --- which is perfectly OK -- then please don't meddle with the browser installation already on the system. As for plugins: You have a .mozilla directory inside your /home ... inside of that directory there should also be a plugins directory. This means you can also install plugins and other stuff locally inside your /home ... without getting into conflict with the things installed by the package manager.

Also you should be aware that programs installed locally into your /home are only available to your user account and not to any other user account. To have things available system-wide (so that e.g. your wife could use those things too when she's logged in into her own account) you'd have to use directory locations such as /usr/local or maybe /opt (I prefer the latter one as commercial UNIX-es do that too ... they put "optional stuff" into /opt, so I'm kinda used to that).

Maybe you'd also be interested to read this:
http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard

[Vic]

Brilliant, and thanks for the information. I do really appreciate it!

[scorp123]

Brilliant, and thanks for the information. I do really appreciate it!

Guess what happened this morning when I logged in? I was notified of an update: Firefox 2.0.0.4 ==> 2.0.0.5

Chances are that on your system this might now lead to collisions. Besides that your local installation in your /home is kinda redundant as the packet manager will now suggest to install the new version anyway.

So safest thing would probably be to remove the installation and remove the symbolic links that you created, and then let the packet manager do its updates.

[Vic]

It is a secondary PC, for my experimentation, and as such is completely expendable as far as the data is concerned.

I took your advice and warning about having non-standard configurations for no good reason, so I formatted the PC and re-installed Mint.

All is well and completely functioning as expected.