Ubuntu18.04 Minecraft配置JDK update-alternatives管理

一、卸载openjdk8

sudo apt-get remove openjdk-8-jdk
sudo apt-get remove openjdk-8-jre-headless

二、安装jdk-17

下载jdk安装文件jdk17-archive-downloads

sudo mkdir -p /usr/lib/jvm/java-17
sudo tar xvf jdk-17.0.4.1_linux-x64_bin.tar.gz -C /usr/lib/jvm/jdk-17
sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk-17/jdk-17.0.4.1/bin/java" 2000
sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/jdk-17/jdk-17.0.4.1/bin/javac" 2000
sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/lib/jvm/jdk-17/jdk-17.0.4.1/bin/javaws" 2000
sudo update-alternatives --install "/usr/local/jdk" "jdk" "/usr/lib/jvm/jdk-17/jdk-17.0.4.1" 2000
sudo update-alternatives --install "/usr/local/jdk" "jdk" "/usr/lib/jvm/jdk-17/jdk-17.0.4.1" 2000
sudo echo export JAVA_HOME=/usr/local/jdk >> /etc/profile
sudo echo export PATH=\$PATH:$JAVA_HOME/bin >> /etc/profile
sudo echo export CLASSPATH=.:\$JAVA_HOME/lib/dt.jar:\$JAVA_HOME/lib/tools.jar >> /etc/profile
source /etc/profile

测试java

java -version
Java HotSpot(TM) 64-Bit Server VM (build 17.0.4.1+1-LTS-2, mixed mode, sharing)

三、安装jdk1.8并切换

下载jdk-8u301-linux-x64.tar.gz文件并解压

sudo mkdir -p /usr/lib/jvm/java-8
sudo tar xvf jdk-8u301-linux-x64.tar.gz -C /usr/lib/jvm/jdk-8
sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/java-8/jdk1.8.0_301/bin/java" 3000
sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/java-8/jdk1.8.0_301/bin/javac" 3000
sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/lib/jvm/java-8/jdk1.8.0_301/bin/javaws" 3000
sudo update-alternatives --install "/usr/local/jdk" "jdk" "/usr/lib/jvm/java-8/jdk1.8.0_301" 3000
sudo update-alternatives --install "/usr/local/jdk" "jdk" "/usr/lib/jvm/java-8/jdk1.8.0_301" 3000

切换Java版本：

sudo update-alternatives --config java