查看已经安装的JDK
[root@izuf61z1rt2fvuhr3u07s0z ~]# rpm -qa|grep jdk
java-1.8.0-openjdk-headless-debug-1.8.0.151-5.b12.el7_4.x86_64
java-1.8.0-openjdk-src-debug-1.8.0.151-5.b12.el7_4.x86_64
copy-jdk-configs-2.2-5.el7_4.noarch
java-1.8.0-openjdk-headless-1.8.0.151-5.b12.el7_4.x86_64
java-1.8.0-openjdk-devel-debug-1.8.0.151-5.b12.el7_4.x86_64
java-1.8.0-openjdk-javadoc-zip-debug-1.8.0.151-5.b12.el7_4.noarch
java-1.8.0-openjdk-javadoc-zip-1.8.0.151-5.b12.el7_4.noarch
java-1.8.0-openjdk-debug-1.8.0.151-5.b12.el7_4.x86_64
java-1.8.0-openjdk-demo-debug-1.8.0.151-5.b12.el7_4.x86_64
java-1.8.0-openjdk-javadoc-debug-1.8.0.151-5.b12.el7_4.noarch
java-1.8.0-openjdk-javadoc-1.8.0.151-5.b12.el7_4.noarch卸载命令：依次全部卸载
[root@izuf61z1rt2fvuhr3u07s0z ~]# yum -y remove java-1.8.0-openjdk-headless-debug-1.8.0.151-5.b12.el7_4.x86_64查看jdk java -version
[root@izuf61z1rt2fvuhr3u07s0z ~]# java -version
-bash: /usr/bin/java: No such file or directory卸载完成，如果还有剩下重来上述步奏
安装JDK