Install and configure jdk from the tar file in Linux

Download the package from http://oracle.com/java under the same terms as users on other platforms. Here is the direct link to JavaSE downloads.

Coming the point I have downloaded JDK 7 (update 4) for Linux x86 (32-bit) – file: jdk-7u21-linux-i586.tar.gz

Step 1:
After downloading the file open the terminal and navigate to the file
tar -xf jdk-7u21-linux-i586.tar.gz
This will extract and create a jdk folder at your current path.

Step 2:
Create a location to keep your new JDK . I prefer and usually use /usr/lib/jvm/
You may need root permission to create the /usr/lib/jvm (hence use sudo).
sudo mkdir /usr/lib/jvm 

Step 3: Move the extracted jdk folder to /usr/lib/jvm/
sudo mv jdk1.7.0_21 /usr/lib/jvm/

Step 4: Now we have to setup our system to use refer to our new jdk
sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk1.7.0_21/bin/java" 1
sudo update-alternatives --config java

And also register Firefox Java Plugin

sudo update-alternatives --install "/usr/lib/mozilla/plugins/libjavaplugin.so" \
"mozilla-javaplugin.so" "/usr/lib/jvm/jdk1.7.0_21/jre/lib/i386/libnpjp2.so" 1
sudo update-alternatives --config mozilla-javaplugin.so

ALL DONE. You can test your java install by
java -version

Finally if you need to add JAVA_HOME variable, you can do so by adding it to the .bashrc file in your home directory
Open .bashrc file using an editor. If you use VI then
vi ~/.bashrc
and add the following 2 lines in your .bashrc file.
JAVA_HOME=/usr/lib/jvm/jdk1.7.0_21/
export JAVA_HOME
There may be other ways to install, but this is what I have followed always.


Cheers