删除CentOS系统自带的jdk

[root@localhost ~]# rpm -qa|grep jdk
java-1.6.0-openjdk-1.6.0.0-1.50.1.11.5.el6_3.x86_64
java-1.7.0-openjdk-1.7.0.9-2.3.4.1.el6_3.x86_64

[root@localhost ~]# rpm -qa|grep gcj
java-1.4.2-gcj-compat-1.4.2.0-40jpp.115  
libgcj-4.1.2-48.el5  

[root@localhost ~]# yum -y remove java java-1.6.0-openjdk-1.6.0.0-1.50.1.11.5.el6_3.x86_64
[root@localhost ~]# yum -y remove java java-1.7.0-openjdk-1.7.0.9-2.3.4.1.el6_3.x86_64
[root@localhost ~]# yum -y remove java java-1.4.2-gcj-compat-1.4.2.0-40jpp.115  
[root@localhost ~]# yum -y remove libgcj-4.1.2-48.el5

[root@localhost ~]# rpm -qa|grep java
java_cup-0.10k-5.el6.i686
java-1.5.0-gcj-1.5.0.0-29.1.el6.i686

[root@localhost ~]# yum -y remove java-1.5.0-gcj-1.5.0.0-29.1.el6.i686

https://blog.csdn.net/liuyuliuyu520/article/details/43084905
https://www.linuxidc.com/Linux/2016-12/138043.htm