查看已安装的JDK:

yum list installed |grep java

查看可安装的JDK：

yum -y list java*

安装JDK:

yum -y install java-1.8.0-openjdk*

卸载已安装的JDK:

yum -y remove java-1.8.0-openjdk-javadoc.x86_64