一 centos7 卸载自带的 jdk

查找系统自带的jdk,卸载自带jdk

rpm -qa | grep java

卸载查询出来的jdk

rpm -e --nodeps java-1.8.0-openjdk-1.8.0.161-2.b14.el7.x86_64

rpm -e --nodeps java-1.8.0-openjdk-headless-1.8.0.161-2.b14.el7.x86_64