The Tutorial shows you Step-by-STep How to Install and Getting-Started with the Oracle-Sun Official Java SE JDK for Debian 6 Squeeze GNOME i386 Desktop.
After Installing you will need to Use the update-alternatives Command Tool to Update your System Java to Oracle Java 1.7 JDK.
To the Article Bottom there is a Link for Quick Start with Java JDK 7 Development and also to Install the Java Web-Servers Tomcat 7 & JBoss 7 Servers on Debian Linux 6.
And this Visual Guide includes the Basic Screenshots of All GUI Steps involved.
The Content give Focus Only to the Essentials Instructions and Commands to make it Easier to Follow.

-
Here Download Oracle-Sun Java SE JDK:
Oracle JDK i586 tar.gzLink to Download the Latest Oracle-Sun Java SE JDK 32-bit Linux Release -
Find and Double-Click on the tar.gz Archive
Extract it Into the /tmp Folder.
-
Open a Root Terminal Window
(Press “Enter” to Execute Commands) -
Relocate JDK 7
Copysu
If Got “User is Not in Sudoers file” then see: How to Enable sudo
Copyif [ ! -d "/usr/lib/jvm" ]; then mkdir /usr/lib/jvm; fi
The above command is used to create a jvm directory if not already there.
Copysudo chown -R root:root /tmp/jdk1.7*
Reiterate the Execution Permission over the Java binaries
Copychmod -R +x /tmp/jdk1.7*/bin
Finally, Shift the Java contents with
Copymv /tmp/jdk1.7* /usr/lib/jvm/
-
Update System Java to 1.7
Copyupdate-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.7*/bin/java 1065
Copyupdate-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.7*/bin/javac 1065
Copyupdate-alternatives --install /usr/bin/jar jar /usr/lib/jvm/jdk1.7*/bin/jar 1065
Copyupdate-alternatives --install /usr/bin/javaws javaws /usr/lib/jvm/jdk1.7*/bin/javaws 1065
-
Getting-Started with Java Development:
Guides to Installing the Tomcat7 Server on Linux: