Step by step installation of JDK 1.6 in Ubuntu

JDK 1.6 Installation in Ubuntu

Install Java JDK 6.0 update 31 on Ubuntu 12.04 LTS

Introduction
The first question is why are we installing an old JDK. The answer is that Oracle JDK 6.0 update 31 is the JDK recommended by Cloudera when installing CDH4 (Cloudera Distribution Hadoop v4).

This is an update to an older version of this post. Mainly I have changed the JDK from 1.6.0_26 to 1.6.0_31 as this is the recommended JDK for CDH4 .

Install Java
I have a 64 bit version of Ubuntu 12.04 LTS installed, so the instructions below only apply to this OS.

Download the Java JDK from http://www.oracle.com/technetwork/java/javasebusiness/downloads/java-archive-downloads-javase6-419409.html#jdk-6u31-oth-JPR .
Click Accept License Agreement
Click jdk-6u31-linux-x64.bin
Login to Oracle.com with your Oracle account
Download the JDK to your ~/Downloads directory
After downloading, open a terminal, then enter the following commands.
cd ~/Downloads
chmod +x jdk-6u31-linux-x64.bin
./jdk-6u31-linux-x64.bin
Note:
The jvm directory is used to organize all JDK/JVM versions in a single parent directory.

sudo mkdir /usr/lib/jvm
sudo mv jdk1.6.0_31 /usr/lib/jvm
The next 3 commands are split across 2 lines per command due to width limits in the blog’s theme.

sudo update-alternatives --install "/usr/bin/java" "java" \
"/usr/lib/jvm/jdk1.6.0_31/bin/java" 1
sudo update-alternatives --install "/usr/bin/javac" "javac" \
"/usr/lib/jvm/jdk1.6.0_31/bin/javac" 1
sudo update-alternatives --install "/usr/bin/javaws" "javaws" \
"/usr/lib/jvm/jdk1.6.0_31/bin/javaws" 1
sudo update-alternatives --config java
You will see output similar to the following (although it’ll differ on your system). Read through the list and find the number for the Oracle JDK installation (/usr/lib/jvm/jdk1.6.0_26/bin/java)

There are 2 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                            Priority   Status
------------------------------------------------------------
* 0            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1051      auto mode
  1            /usr/lib/jvm/jdk1.6.0_31/bin/java                1         manual mode
  2            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1051      manual mode
On my system I did the following (change the number that is appropriate for your system):
Press 1 on your keyboard, then press Enter.

sudo update-alternatives --config javac
Follow steps similar to those listed above if you are presented with a list of options. In my case, I had not previously installed the OpenJDK javac binary, so my output looked like the following:

There is only one alternative in link group javac: /usr/lib/jvm/jdk1.6.0_31/bin/javac
Nothing to configure.
sudo update-alternatives --config javaws
As with javac, I did not have the OpenJDK version of javaws installed, so my output was simple. However, if you get a list of options, just type in the number of the path to the Oracle javaws command, and press Enter.

There is only one alternative in link group javaws: /usr/lib/jvm/jdk1.6.0_31/bin/javaws
Nothing to configure.
As a final step, let’s test each of the commands to ensure everything is setup correctly.

java -version
The output should be:
java version "1.6.0_31"
Java(TM) SE Runtime Environment (build 1.6.0_31-b04)
Java HotSpot(TM) 64-Bit Server VM (build 20.6-b01, mixed mode)

javac -version
The output should be:
javac 1.6.0_31

javaws -version
The output should be:
Java(TM) Web Start 1.6.0_31
which is followed by a long usage message.

Create the JAVA_HOME environment variable
Open a terminal, then enter the following commands:

sudo vi /etc/environment
WARNING
WordPress displays the quotes around the JAVA_HOME value below as magic quotes. This will cause problems when you try to use your JVM in certain applications.

Do not copy/paste the JAVA_HOME value below. Or if you do, ensure that you change magic quotes to straight quotes in your editor.

Enter the following at the bottom of the file:
JAVA_HOME="/usr/lib/jvm/jdk1.6.0_31"

Type the following commands to finish the setup and verify that everything is setup correctly.

source /etc/environment
echo $JAVA_HOME
You should see the following output:

/usr/lib/jvm/jdk1.6.0_31
Lastly, verify that JAVA_HOME is set correctly for the sudo user:

sudo env | grep JAVA_HOME
That’s it, the JDK 6.0 update 31 is installed.

Extremely helpful! Thank you so much

Thank you very much. Update last version to 6u45.

Thank you very much.

Thank you!

Thank you so much (y)
;)

Thanks :) It helped a lot !

sudo update-alternatives --install "/usr/bin/java" "java"

is the key step.

Thanks a lot and it is very useful!

java home is not found from all terminal, what might be the reason

THANK YOU!!

Your simple and detailed steps helped me...