转: CentOS安装jdk8

from: http://tecadmin.net/install-java-8-on-centos-rhel-and-fedora/

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.

This article will help you to Install JAVA 8 (JDK 8u66) or update on your system. Read instruction carefully for downloading java from Linux command line. To Install Java 8 in Ubuntu and LinuxMint read This Article.

Downloading Latest Java Archive

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

For 64Bit

# 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/8u111-b14/jdk-8u111-linux-x64.tar.gz"
 
# tar xzf jdk-8u111-linux-x64.tar.gz

For 32Bit

# 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/8u111-b14/jdk-8u111-linux-i586.tar.gz"
 
# tar xzf jdk-8u111-linux-i586.tar.gz

Note: If Above wget command does not work for you watch this example video to download java source archive using terminal.

Install Java with Alternatives

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

# cd /opt/jdk1.8.0_111/
# alternatives --install /usr/bin/java java /opt/jdk1.8.0_111/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_111/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

# alternatives --install /usr/bin/jar jar /opt/jdk1.8.0_111/bin/jar 2
# alternatives --install /usr/bin/javac javac /opt/jdk1.8.0_111/bin/javac 2
# alternatives --set jar /opt/jdk1.8.0_111/bin/jar
# alternatives --set javac /opt/jdk1.8.0_111/bin/javac

Check Installed Java Version

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

root@tecadmin ~# java -version
 
java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)

Configuring 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

# export JAVA_HOME=/opt/jdk1.8.0_111

Setup JRE_HOME Variable

# export JRE_HOME=/opt/jdk1.8.0_111/jre

Setup PATH Variable

# export PATH=$PATH:/opt/jdk1.8.0_111/bin:/opt/jdk1.8.0_111/jre/bin

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