Thursday, 24 October 2013

Installing and configuring Java in cent OS

Most of the Linux operating systems comes with pre-installed OpenJDK package to run java-based applications and plugins.But in certain cases we need Sun/Oracle Java program to compile and run
particular development applications.

1. Download java from

2. install java using rpm -uvh
   ## Install Java on 32-Bit OS ##
   # rpm -Uvh jdk-7u45-linux-i586.rpm
   # rpm -Uvh jdk-7u45-linux-i586.rpm

   ## Install Java on 64-Bit OS ##
   # rpm -Uvh jdk-7u45-linux-x64.rpm
   # rpm -Uvh jdk-7u45-linux-x64.rpm

3. check java installed
   # java -version

   output should be
   java version "1.7.0_45"

4. Setting up java environment variables
The easiest way to set an environment variable in CentOS is to use export as in

$> export JAVA_HOME=/usr/java/jdk.1.7.0_45


However, variables will disappear the moment you exit the shell. Obviously this is not helpful when setting environment variables that need to persist even when the system reboots.In such cases, you need to set the variables within the system wide profile. In CentOS , the folder /etc/profile.d/ is the recommended place to add  customizations to the system profile.

5. Create a new file called
vim /etc/profile.d/

6. Copy paste the below content in

export JRE_HOME=/usr/java/jdk.1.7.0_45/jre
export PATH=$PATH:$JRE_HOME/bin
export JAVA_HOME=/usr/java/jdk.1.7.0_45
export PATH=$PATH:$JAVA_HOME/bin

7.  If you want to load the environment variables within without having  to restart the machine, you can use the source command as in:
   $> source