A walking through to install JDK on CentOS.

Download JDK

You need to agree OTN license terms before downloading the package. So if you are using wget or curl, you need to add more parameters to avoid only downloading a webpage instead of the real package.

wget

wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u112-b15/jdk-8u112-linux-x64.rpm

curl

curl -v -j -k -L -H "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u112-b15/jdk-8u112-linux-x64.rpm > jdk-8u112-linux-x64.rpm

  • -j -> junk cookies
  • -k -> ignore certificates
  • -L -> follow redirects
  • -H -> headers (–header)

Install JDK RPM

You can install the RPM manually or use yum:

yum localinstall jdk-8u112-linux-x64.rpm -y

After it is completed, you will see below in folder /usr/java:

jdk1.8.0_112

latest -> /usr/java/jdk1.8.0_112

default -> /usr/java/latest

Install Java with Alternatives

To avoid configuring Java again when you upgrade to a newer Java version, you can utilize above soft link to hide the version from configuration.

Check current alternatives environment

alternatives --config java

There is 1 program which provide 'java'.

  Selection    Command
-----------------------------------------------
*+ 1           /opt/jdk1.7.0_71/bin/java

Enter to keep the current selection[+], or type selection number: ^C

Install new Java version

To not break existing environment we need to install Java using below alternative command:

alternatives --install /usr/bin/java java /usr/java/default/bin/java 2

Then check alternatives environment again and choose new installed Java version

alternatives --config java

There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*  1           /opt/jdk1.7.0_71/bin/java
 + 2           /usr/java/default/bin/java

Enter to keep the current selection[+], or type selection number: 2

At this point Java 8 has been successfully installed on your system. Let’s set up javac/jar as well:

alternatives --install /usr/bin/jar jar /usr/java/default/bin/jar 2
alternatives --install /usr/bin/javac javac /usr/java/default/bin/javac 2
alternatives --set jar /usr/java/default/bin/jar
alternatives --set javac /usr/java/default/bin/javac

Check Installed Java Version

java --version

java version "1.8.0_112"
Java(TM) SE Runtime Environment (build 1.8.0_112-b15)
Java HotSpot(TM) 64-Bit Server VM (build 25.112-b15, mixed mode)

Configure Environment Variables

export JAVA_HOME=/usr/java/default
export JRE_HOME=/usr/java/default/jre
export PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin