On CentOs we need to install JDK for some programs like Ant, Maven and etc. If you are already installed Java JDK and you want to update it, you can start from Section 0.

Section 0 — Check and Remove old versions

Firstly update your server

yum update

Then, check if any older JDK versions are installed in your system.

rpm -qa | grep -E '^open[jre|jdk]|j[re|dk]'

Check Java version

java -version

If there are other versions you can remove them via this command

yum remove java-1.8.0-openjdkor yum remove jdk-1.8.0

Note: Instead of 1.8.0 you can write your version

Section 1 — Install Oracle Java JDK (version 1)

cd ~/Downloadswget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "https://download.oracle.com/otn-pub/java/jdk/16.0.2%2B7/d4a915d82b4c4fbb9bde534da945d746/jdk-16.0.2_linux-x64_bin.rpm"

Note: You can change this download link and install another version. For another version go there
For example: You can download JDK 11 like this

wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "https://download.oracle.com/otn/java/jdk/11.0.12%2B8/f411702ca7704a54a79ead0c2e0942a3/jdk-11.0.12_linux-x64_bin.rpm"

Extract Jdk 16

rpm -ivh jdk-16.0.2_linux-x64_bin.rpm

Check Java version

java -version

Output:

java version “16.0.2” 2021–07–20
Java(TM) SE Runtime Environment (build 16.0.2+7–67)
Java HotSpot(TM) 64-Bit Server VM (build 16.0.2+7–67, mixed mode, sharing)

Setup Global Environment Variables

We can easily set the environment variables using the export command as shown below.

export JAVA_HOME=/usr/java/jdk-16.0.2/
export PATH=$PATH:$JAVA_HOME

Now, let us check for the environment variables using commands:

echo $JAVA_HOME

Output:

/usr/java/jdk-16.0.2/

The path will be disappear when the system reboots so to make it permanent, you have to add the paths in the system profile.

Create a file called java.sh under /etc/profile.d/ directory.

nano /etc/profile.d/java.sh#!/bin/bash
JAVA_HOME=/usr/java/jdk-16.0.2/
PATH=$JAVA_HOME/bin:$PATH
export PATH JAVA_HOME
export CLASSPATH=.

Save and close the file.

Make it executable :

chmod +x /etc/profile.d/java.sh

Then, set the environment variables permanent

source /etc/profile.d/java.sh

That’s it.

Section 2— Install Oracle Java JDK (version 2)

cd ~/Downloadswget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "https://download.oracle.com/otn-pub/java/jdk/16.0.2%2B7/d4a915d82b4c4fbb9bde534da945d746/jdk-16.0.2_linux-x64_bin.rpm"

Note: You can change this download link and install another version. For another version go there

sudo yum localinstall jdk-16.0.2_linux-x64_bin.rpm

Now Java should be installed at /usr/java/jdk-16.0.2, and linked from /usr/bin/java.

You may delete the archive file that you downloaded earlier:

rm ~/Downloads/jdk-16.0.2_linux-x64_bin.rpm

Congratulations! You have installed Oracle Java 16 JDK.