After a long wait, finally Java SE Development Kit 8 is available to download. JDK 8 has been released on Mar,18 2014 for general availability with the many featured enhancements. You can find all the enhancements in JDK 8 here.

Java on Linux

This article will help you to Install JAVA 8 (JDK/JRE 8u144) or update on your system. Read the instruction carefully before downloading Java from Linux command line. To Install Java 8 in Ubuntu and LinuxMint read This Article.

Step 1 – Download Latest Java Archive

Download latest Java SE Development Kit 8 release from its official download page or use following commands to download from shell.

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# cd /opt/
# wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u144-b01/090f390dda5b47b9b721c7dfaa008135/jdk-8u144-linux-x64.tar.gz"

# tar xzf jdk-8u144-linux-x64.tar.gz

Step 2 – Install Java 8 with Alternatives

After extracting archive file use alternatives command to install it. alternatives command is available in chkconfig package.

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# cd /opt/jdk1.8.0_144/
# alternatives --install /usr/bin/java java /opt/jdk1.8.0_144/bin/java 2
# alternatives --config java

There are 3 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*  1           /opt/jdk1.7.0_71/bin/java
 + 2           /opt/jdk1.8.0_45/bin/java
   3           /opt/jdk1.8.0_91/bin/java
   4           /opt/jdk1.8.0_144/bin/java

Enter to keep the current selection[+], or type selection number: 4

At this point JAVA 8 has been successfully installed on your system. We also recommend to setup javac and jar commands path using alternatives

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# alternatives --install /usr/bin/jar jar /opt/jdk1.8.0_144/bin/jar 2
# alternatives --install /usr/bin/javac javac /opt/jdk1.8.0_144/bin/javac 2
# alternatives --set jar /opt/jdk1.8.0_144/bin/jar
# alternatives --set javac /opt/jdk1.8.0_144/bin/javac

Step 3 – Check Installed Java Version

Check the installed Java version on your system using following command.

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root@tecadmin ~# java -version

java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)

Step 4 – Setup Java Environment Variables

Most of Java based application’s uses environment variables to work. Set the Java environment variables using following commands

  • Setup JAVA_HOME Variable
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# export JAVA_HOME=/opt/jdk1.8.0_144
  • Setup JRE_HOME Variable
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# export JRE_HOME=/opt/jdk1.8.0_144/jre
  • Setup PATH Variable
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# export PATH=$PATH:/opt/jdk1.8.0_144/bin:/opt/jdk1.8.0_144/jre/bin

Also put all above environment variables in /etc/environment file for auto loading on system boot.

原文地址：https://tecadmin.net/install-java-8-on-centos-rhel-and-fedora/

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