Step 1: Download
Go to the Oracle site and select your Java. http://www.oracle.com/technetwork/java/javase/downloads/index.html
Step 2: Extract
I downloaded Java 7 JDK so to extract was simply
tar -xvf ~/Downloads/jdk-7u5-linux-x64.tar.gz
Step 3: Move
When you install Java via a package manager for a Debian system the install location is /usr/lib/jvm/. If you go have a look at that folder you should see all the installed version of java on you pc. So to move the extracted folder:
sudo mv ~/Downloads/jdk1.7.0_05 /usr/lib/jvm/java-7-sunjdk
This will move and rename the folder to java-7-sunjdk
Step 4: Install
Linux has this amazing command to where you can link commands with the option of easy switching.
So to list all the currently installed options for the command java type
user@user-SERVER ~ $ sudo update-alternatives --list java
/usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java
As you can see here I only have Java 6 OpenJDK installed for the command java. Now to add my Oracle java I will have to install a new option as follow:
sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/java-7-sunjdk/bin/java" 1
Now if I rerun the list command I have two options for the java command
user@user-SERVER ~ $ sudo update-alternatives --list java
/usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java
/usr/lib/jvm/java-7-sunjdk/bin/java
Step 5: Select Default
Now to select which one must be executed by default if I run the java command:
user@user-SERVER /usr/lib/jvm $ sudo update-alternatives --config java
There are 2 choices for the alternative java (providing /usr/bin/java).
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java 1061 auto mode
1 /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java 1061 manual mode
2 /usr/lib/jvm/java-7-sunjdk/bin/java 1 manual mode
Press enter to keep the current choice[*], or type selection number: 2
update-alternatives: using /usr/lib/jvm/java-7-sunjdk/bin/java to provide /usr/bin/java (java) in manual mode.
When you run this command you are show the current default and all the available options. In my case I selected option 2 as my new default.
Step 6: Jippy
Your all done below are just some command for the ease to map the javaws, javac and jps. Your more than welcome to add more.
sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/java-7-sunjdk/bin/javac" 1
sudo update-alternatives --config javac
sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/lib/jvm/java-7-sunjdk/bin/javaws" 1
sudo update-alternatives --config javaws
sudo update-alternatives --install "/usr/bin/jps" "jps" "/usr/lib/jvm/java-7-sunjdk/bin/jps" 1
sudo update-alternatives --config jps
