How to install java in unix

In this post i am going to teach you how to install java in you unix box in order to use hadoop

Before reading this please read Basic Unix command because knowledge of unix commands are required for installing java in unix.

Dowload jdk 1.8 from the below link

http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

Download this file  jdk-8u31-linux-x64.tar.gz

copy  it to any folder e.x  /usr/local/java/

$ sudo mkdir /usr/local/java

$ sudo chmod 777 /usr/local/java

$ sudo cp /mnt/hgfs/sharedDrive/jdk-8u31-linux-x64.tar.gz   to /usr/local/java

Untar it using the below command

$ sudo tar xvzf  jdk-8u31-linux-x64.tar.gz

Edit the system PATH file /etc/profile and add the following system variables

$ geany /etc/profile

JAVA_HOME=/usr/local/java/jdk1.8.0_31
JRE_HOME=$JAVA_HOME/jre
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
export JAVA_HOME
export JRE_HOME
export PATH

Inform your Ubuntu Linux system where your Oracle Java JDK/JRE is located.

sudo update-alternatives --install "/usr/bin/java" "java" "/usr/local/java/jdk1.8.0_121/jre/bin/java" 1

sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/local/java/jdk1.8.0_121/bin/javac" 1

Inform your Ubuntu Linux system that Oracle Java JDK/JRE must be the default Java.

sudo update-alternatives --set java /usr/local/java/jdk1.8.0_121/jre/bin/java

sudo update-alternatives --set javac /usr/local/java/jdk1.8.0_121/bin/javac

Reload your system wide PATH /etc/profile by typing the following command:

$  .   /etc/profile

Test to see if Oracle Java was installed correctly on your system. Run the following commands and note the version of Java

$ java -version

Above command will show you the java version if successfully installed