Installing Java 8 on CentOS 7


Step 1: Update


As a matter of best practice we’ll update before installing any new programs:

yum -y update


Step 2: Install Java 8


yum install java-1.8.0-openjdk


Step 3:  Verify Java is Installed


java -version


**Example Output:**

java -version
openjdk version "1.8.0_191"
OpenJDK Runtime Environment (build 1.8.0_191-b12)
OpenJDK 64-Bit Server VM (build 25.191-b12, mixed mode)


Set Java’s Home Environment


Step 1: Find Java’s Path


Let’s set the** JAVA_HOME** variable, using the following command will give us a path so we can set the variable.

update-alternatives --config java


You’ll see a prompt to “Enter to keep the current selection[+], or type selection number:”, if you had multiple Java version you could set the default here, but all we need is the path of Java so we can exit pressing enter.  The highlighted area is the path we will need to copy/paste into our .bash_profile file.

Selection    Command
-----------------------------------------------
*+ 1           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64/jre/bin/java)</code?


Step 2: Setting Java’s Path in Your Environment


After copying your Java’s path, open the .bash_profile with your text editor.

vim .bash_profile


Export your Java path into the .bash_profile by adding the following to the bottom of the file. (Your path may look different from mine, and it’s not important that they vary.)

export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64/jre/bin/java


Refresh the File:

source .bash_profile


When you use the** JAVA_HOME** variable you’ll now be able to see the path you set.

echo $JAVA_HOME


**Example Output:**

/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64/jre/bin/java




参考资料：

https://www.liquidweb.com/kb/install-java-8-on-centos-7/