Procedure for manually installing Java (jdk1.8) on Linux (CentOS7)

The materials created on 2017/06/03 will be uploaded.

An easy way to install Java on Linux (CentOS7) is to use the yum command or rpm command, but here we will show you how to install it manually.

1. Log in to CentOS7 and switch to the root user.

$ su -
#

2. Download "jdk-8u131-linux-x64.tar.gz" from the Oracle web page.

# curl -OL --header "Cookie: oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u131-b11/d54c1d3a095b4ff2b6607d096fa80163/jdk-8u131-linux-x64.tar.gz"

(The URL of the link destination may have changed?) (You may download it from your browser instead of using the command.)

3. Unzip "jdk-8u131-linux-x64.tar.gz".

# tar xvzf ./jdk-8u131-linux-x64.tar.gz

("Jdk1.8.0_131" is created.)

4. Copy (move) "jdk1.8.0_131" under / opt "

# mv ./jdk1.8.0_131 /opt

5. Create a symbolic link to absorb path changes due to future version upgrades of jdk.

# ln -s /opt/jdk1.8.0_131 /opt/java

6. Exit the root user and return to the logged-in user.

# exit
$

7. Create a Java environment file ".java.env".

shell:.java.env

export JAVA_HOME=/opt/java
export PATH=$JAVA_HOME/bin:$PATH
export CLASSPATH=.

8. Read the created java environment file.

$ source .java.env

9. Check the version of jdk installed by Java command.

$ java –version
(The following is displayed.)
java version "1.8.0_131"
Java(TM) SE Runtime Environment (build 1.8.0_131-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)

10. Add the following to ".bash_profile" in the user's home directory so that environment variables are set at login.

.bash_profile

・ ・ ・ ・ ・ ・ ・ ・
source .java.env ← Add this line

[Environment variables]

This time, ".java.env" was created and the environment was set with the source command, but if the following files are placed under the "/etc/profile.d" directory, the environment variables will be set at login.

shell:./etc/profile.d/java.sh

#!/bin/sh
export JAVA_HOME=/opt/java
export PATH=$JAVA_HOME/bin:$PATH
export CLASSPATH=.

that's all