1、查看已经安装的jdk
rpm -qa|grep jdk
2、卸载命令
yum -y remove java-1.8.0-openjdk-headless-debug-1.8.0.151-5.b12.el7_4.x86_64
3、卸载完成之后Java命令不被识别
# java -version
-bash: /usr/bin/java: No such file or director
设置java环境变量
export JAVA_HOME=/usr/local/jdk/jdk1.8.0_221 export CLASSPATH=$:CLASSPATH:$JAVA_HOME/lib/ export PATH=$PATH:$JAVA_HOME/bin
source /etc/profile
