ubuntu 16.04 手動安裝Java過程

參考：
https://www.vultr.com/docs/how-to-manually-install-java-8-on-ubuntu-16-04

所需Java軟件包https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

下載對應版本，到用戶根目錄下的Downloads

sudo mkdir /usr/lib/jvm
cd /usr/lib/jvm
sudo tar -xvzf ~/Downloads/jdk-8u192-linux-x64.tar.gz

sudo vim /etc/environment

內容替換成：
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/lib/jvm/jdk1.8.0_192/bin:/usr/lib/jvm/jdk1.8.0_192/db/bin:/usr/lib/jvm/jdk1.8.0_192/jre/bin"
J2SDKDIR="/usr/lib/jvm/jdk1.8.0_192"
J2REDIR="/usr/lib/jvm/jdk1.8.0_192/jre*
JAVA_HOME="/usr/lib/jvm/jdk1.8.0_192"
DERBY_HOME="/usr/lib/jvm/jdk1.8.0_192/db"

# sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk1.8.0_192/bin/java" 0
# sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/jdk1.8.0_192/bin/javac" 0
# sudo update-alternatives --set java /usr/lib/jvm/jdk1.8.0_192/bin/java
# sudo update-alternatives --set javac /usr/lib/jvm/jdk1.8.0_192/bin/javac

update-alternatives --list java
update-alternatives --list javac

java -version

出現：
java version “1.8.0_192”
Java™ SE Runtime Environment (build 1.8.0_192-b12)
Java HotSpot™ 64-Bit Server VM (build 25.192-b12, mixed mode)
6.

javac -version

出現：
javac 1.8.0_192

成功！

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