Install Java plugin to firefox in Ubuntu

Ubuntu:
1. Download the JRE (Java Runtime Environment) / JDK (Java Development Kit) 7 from here:
The file type for Ubuntu is the .tar.gz
Note: The JDK is for developers. Do not download unless you plan on programming in Java.
2. Unpack (or untar, or extract) the .tar.gz file in the desired directory. Type:

tar -zxvf filename

3. Install Java 1.7 to alternatives. Type:

sudo update-alternatives --install /usr/bin/java java /your/java/directory/jre/bin/java 3

Note: Replace /your/java/directory/, with the directory where you extracted the .tar.gz
4. Choose your Java version using alternatives. Type:

sudo update-alternatives –config java

Then choose the option that points to your Java 7 directory.
Note: If you have chosen the JDK, your javac will not be updated. Typing the javac -version command will return the previous Java’s version javac. I do not know how to fix this.
5. Configure the Java browser plugin.
You will have to use a symbolic link to configure the plugin.
Type:

ln -s /your/java/directory/jre/lib/your system architecture/libnpjp.so /your/brower/plugins/directory

Note: /your/java/directory/ is wherever you extracted the .tar.gz
Also, /your system architecture/ is the architecture type of the Java .tar.gz file you downloaded. This will either be i386, or amd64. If you are unsure which, open a file manager, go to your Java directory, and go to the jre/lib/ directory. If a folder entitled amd64 is there, you have the x64-bit version. If not, you have the x32-bit.
Another thing to note, the /your/browser/plugins/directory/ is your browser’s plugins directory. Example: if you are using Mozilla’s Firefox, your plugins directory is /usr/lib/mozilla/plugins/
6. Test the plugin. Restart your browser, and go to
Java Tester
Click the Java Version button. If the pink box says Java 1.7.0 from Oracle, you have configured the plugin correctly.
Installing Java 1.7 goodness for Ubuntu. Enjoy