centos 7.0. Installation of offline JDK1.8 Detailed method

View the java warehouse version

yum list |grep java

View installed versions of java jdk

rpm -qa | grep java

If no information is displayed, the jdk version has not been installed

If the following information is displayed:

rpm -qa|grep jdk
java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64 
 java-1.7.0-openjdk-1.7.0.91-2.6.2.3.el7.x86_64 
 java-1.7.0-openjdk-headless-1.7.0.91-2.6.2.3.el7.x86_64 
 java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64

Uninstall command

yum -y remove java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64

The Java command is not recognized after the uninstall completes

java -version

bash: java: command not found...

Start the installation

Go to the website to download jdk: http: / / www oracle. com/technetwork/java/javase downloads/jdk8 - downloads - 2133151. html

Unzip to the installation directory

The current version is jdk1.8.172

 jdk-8u172-linux-x64.gz

Create installation directory

cd home; 
 adduser hadoop; 
 passwd hadoop; 
 whereis sudoers 
 ls -l /etc/sudoers

Add writable permissions

chmod -v u+w /etc/sudoers

Then edit the /etc/sudoers file

vi /etc/sudoers

Add the following hadoop code:

Allow root to run any commands anywhere
root ALL=(ALL) ALL 
 hadoop ALL=(ALL) ALL #this is new add user 
 // -- -- -- -- -  
ls -l /etc/sudoers

Remove writable permissions

chmod -v u-w /etc/sudoers 
 sudo -u hadoop 
 sudo cat /etc/passwd

hadoop users are now sudo authorized users.

tar -zxvf jdk-8u172-linux-x64.gz -C /home/hadoop/java/

Change directory name

mv jdk1.8.0_172/ jdk1.8/

Go to the jdk folder and get the absolute directory path

pwd

[root@hadoop-localhost jdk1.8]# pwd 
 /home/hadoop/java/jdk1.8

(my absolute path is: / home/hadoop java/jdk1. 8)

jdk configuration

Use the vim command to open the system's environment variable configuration file:

vi /etc/profile

At the end of profile file, add:

//## JAVA 
 export JAVA_HOME=/home/hadoop/java/jdk1.8 
 //jdk The absolute path of (mine is: /home/hadoop/java/jdk1.8 ) 
export PATH=PATH: 
PATH:
JAVA_HOME/bin

jdk configuration validation

Enable the configuration file first

source /etc/profile
[root@hadoop-localhost jdk1.8]# source /etc/profile
java -version
[root@hadoop-localhost jdk1.8]# java -version 
 java version  " 1.8.0_172 "  
Java(TM) SE Runtime Environment (build 1.8.0_172-b11) 
 Java HotSpot(TM) 64-Bit Server VM (build 25.172-b11, mixed mode)

conclusion