To get started, download Java JDK package from here.
When prompted with the screen below, choose to save the file.
After saving, extract the downloaded package by running the commands below. This assumes that the package was downloaded in your Downloads folder.
tar -xvf ~/Downloads/jdk-7u3-linux-i586.tar.gz
Next, create a folder for Java JDK files and folders by running the commands below.
sudo mkdir -p /usr/lib/jvm/jdk1.7.0
Then move all the JDK files and folders to the new location by running the commands below.
sudo mv jdk1.7.0_03/* /usr/lib/jvm/jdk1.7.0/
Next, copy and paste each command as shown below one-at-a-time to enable Java JDK. Remember to press Enter after each line.
sudo update-alternatives –install “/usr/bin/java” “java” “/usr/lib/jvm/jdk1.7.0/bin/java” 1
sudo update-alternatives –install “/usr/bin/javac” “javac” “/usr/lib/jvm/jdk1.7.0/bin/javac” 1
sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/lib/jvm/jdk1.7.0/bin/javaws" 1
Then create a Mozilla plugins folder in your home directory.
Finally, create a symbolic link to your Mozilla plugins folder. For 64-bit systems, replace ‘i386’ with ‘amd64’.
ln -s /usr/lib/jvm/jdk1.7.0/jre/lib/i386/libnpjp2.so ~/.mozilla/plugins/
That’s it! Enjoy!