ubuntu16.04LTS安装JDK8

1.Java8下载地址
http://www.oracle.com/technetwork/cn/java/javase/downloads/jdk8-downloads-2133151-zhs.html
2、将jdk-8u112-linux-x64.tar.gz拷到/home/普通用户名 的文件夹下

然后在空白处右击 在终端打开 执行解压命令
tar zxvf jdk-8u112-linux-x64.tar.gz
而后将解压的文件移动到 /opt 下 需要切换到root用户下，命令如下：

zhenqi@zhenqi-virtual-machine:~$ su root密码： root@zhenqi-virtual-machine:/home/zhenqi# mv jdk1.8.0_112 /optroot@zhenqi-virtual-machine:/home/zhenqi# cd /optroot@zhenqi-virtual-machine:/opt# lsjdk1.8.0_112root@zhenqi-virtual-machine:/opt# ls -l总用量 4drwxr-xr-x 8 zhenqi zhenqi 4096 9月  23 12:24 jdk1.8.0_112

3、在/bin目录下创建java软链接

root@zhenqi-virtual-machine:/opt# cd /binroot@zhenqi-virtual-machine:/bin# ln -s /opt/jdk1.8.0_112/bin/java javaroot@zhenqi-virtual-machine:/bin# java -versionjava version "1.8.0_112"Java(TM) SE Runtime Environment (build 1.8.0_112-b15)Java HotSpot(TM) 64-Bit Server VM (build 25.112-b15, mixed mode)

4、 设置Java环境

root@zhenqi-virtual-machine:/bin# gedit /etc/profile

export JAVA_HOME=/opt/jdk1.8.0_112export JRE_HOME=${JAVA_HOME}/jreexport CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/libexport PATH={JAVA_HOME}/bin:$PATH

oot@zhenqi-virtual-machine:/bin# source /etc/profile

5.验证

oot@zhenqi-virtual-machine:/bin# echo $JAVA_HOME/opt/jdk1.8.0_112root@zhenqi-virtual-machine:/bin# java -versionjava version "1.8.0_112"Java(TM) SE Runtime Environment (build 1.8.0_112-b15)Java HotSpot(TM) 64-Bit Server VM (build 25.112-b15, mixed mode)root@zhenqi-virtual-machine:/bin# 

javac出现如下问题？

则需要更改ubuntu的默认jdk，执行命令如下：

sudo update-alternatives --install /usr/bin/javac javac /opt/jdk1.8.0_112/bin/javac 300sudo update-alternatives --install /usr/bin/java java /opt/jdk1.8.0_112/bin/java 300

在执行javac就可以了。如下图：