How to install Java (JRE) on Ubuntu server

The following instructions will help you to install Oracle Java 7 JRE on Ubuntu 12.04 Server. Please follow these steps only when you install Java on a fresh server.

To remove the open JRE and to install the Oracle Java, you can refer my post here.

Step 1: First check whether the Ubuntu Linux operating system architecture is 32-bit or 64-bit. Run the following command,

root@ubuntusrv:~# uname -a

Linux ubuntusrv 3.2.0-29-generic #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

So in my case it is 64 bit OS

Step 2: Check whether Java is installed or not.

root@ubuntusrv:~# java -version

The program 'java' can be found in the following packages:

 * default-jre

 * gcj-4.6-jre-headless

 * openjdk-6-jre-headless

 * gcj-4.5-jre-headless

 * openjdk-7-jre-headless

Try: apt-get install <selected package>

The above output tells us that java is not installed.

Step 3: Then create a directory called java in /ust/local. This directory will be used to hold all java binaries

root@ubuntusrv:~# sudo mkdir -p /usr/local/java

Step 4: Now download the latest version of java from here

http://www.oracle.com/technetwork/java/javase/downloads/index.html

Note:

You can download the Java from any windows machine and then you can use WinSCP to copy the same

Step 5: Now copy the downloaded file and extract the same using the following commands

root@ubuntusrv:/usr/local/java# cd /usr/local/java/

root@ubuntusrv:/usr/local/java# sudo tar xvzf jre-7u51-linux-x64.tar.gz

Now remove the downloaded archive file

root@ubuntusrv:/usr/local/java# rm jre-7u51-linux-x64.tar.gz

Step 6: Now add the java variables to /etc/environment file as follows

JAVA_HOME=/usr/local/java/jre1.7.0_51

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/java/jre1.7.0_51/bin"

Note:

          :/usr/local/java/jre1.7.0_51/bin has to be appended to the exsisting line

             jre1.7.0_51 is the directory extracted using tar command in the previous step

Step 7: Now restart the server and check the Java installation with the following command

root@ubuntusrv:~# java -version

You will get a response like this

java version "1.7.0_51"

Java(TM) SE Runtime Environment (build 1.7.0_51-b13)

Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)

Step 8: Run the below commands to update the java installation

 sudo update-alternatives --install "/usr/bin/java" "java" "/usr/local/java/jre1.7.0_51/bin/java" 1

sudo update-alternatives --set java /usr/local/java/jre1.7.0_51/bin/java

You are done. Your Server is ready with latest java.