Use alternatives utility to update JDK

At the prompt, type

sudo update-alternatives --config java

The current available java installs would be displayed

Selection    Command
———————————————–
*  1           /usr/lib/jvm/jre-1.6.0-openjdk/bin/java
2           /usr/lib/jvm/jre-1.4.2-gcj/bin/java

To get out of the prompt without make changes, hit Ctrl+C

To add a new jdk, I downloaded the jdk-6u-linux-i586.bin from the Oracle Java site. Unzip it

chmod 755 jdk-6u27-linux-i586.bin

./jdk-6u27-linux-i586.bin

It unzip it to a directory jdk1.6.0_27. I moved it to /usr/lib/jvm,

mv jdk1.6.0_27 /usr/lib/jvm

Then install the jdk1.6.0_27 as a Java alternative. The number 3 is for the priority.

update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.6.0_27/bin/java 3

Now if you do “update-alternatives –config java” again, you would see jdk1.6.0_27 got added as a new alternative. Type 3 and hit Enter to select.

Selection    Command
———————————————–
+ 1           /usr/lib/jvm/jre-1.6.0-openjdk/bin/java
2           /usr/lib/jvm/jre-1.4.2-gcj/bin/java
3           /usr/lib/jvm/jdk1.6.0_27/bin/java
Enter to keep the current selection[+], or type selection number: 3

Test by typing “java -version”

[root@VM1 ~ ]# java -version
java version “1.6.0_27”
Java(TM) SE Runtime Environment (build 1.6.0_27-b07)
Java HotSpot(TM) Client VM (build 20.2-b06, mixed mode, sharing)