Install Sun Java 6

1.Install sun java6 sdk
# sudo apt-get install sun-java6-bin sun-java6-jre sun-java6-jdk

2.Setup java6 as default java version
# sudo update-java-alternatives -s java-6-sun

3.defines the default system JVM search order
# vim /etc/jvm
insert the line at top of the file /etc/jvm
/usr/lib/jvm/java-6-sun

4.Setup the environment variable
# sudo vi $HOME/.bash_profile
add lines at the bottom of the file
export JAVA_HOME=/usr/lib/jvm/java-6-sun
export PATH=$PATH:$JAVA_HOME/bin

5.confirm jdk version
#java -version
java version "1.6.0_13"
Java(TM) SE Runtime Environment (build 1.6.0_13-b03)
Java HotSpot(TM) Server VM (build 11.3-b02, mixed mode)

6.write HelloWorld.java to test java runtime environment
# vim HelloWorld.java
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}

7. compile and run java program
# javac HelloWorld.java
# java HelloWorld
Hello, World!