1.在安裝了Oracle的jdk之後發現系統帶有openjdk會出現下列情況，就是java -version和javac -version會出現不一樣的狀態
[[email protected] ~]# java -version
java version “1.7.0_45”
OpenJDK Runtime Environment (rhel-2.4.3.3.el6-x86_64 u45-b15)
OpenJDK 64-Bit Server VM (build 24.45-b08, mixed mode)
[[email protected] ~]# javac -version
javac 1.6.0_45

1.2
此時可以查出openjdk相關的檔案並且刪除它
[[email protected] ~]# rpm -qa |grep java
java-1.6.0-openjdk-1.6.0.0-1.66.1.13.0.el6.x86_64
tzdata-java-2013g-1.el6.noarch
java-1.7.0-openjdk-1.7.0.45-2.4.3.3.el6.x86_64
[[email protected] ~]# rpm -e –nodeps java-1.6.0-openjdk-1.6.0.0-1.66.1.13.0.el6.x86_64
[[email protected] ~]# rpm -e –nodeps java-1.7.0-openjdk-1.7.0.45-2.4.3.3.el6.x86_64
[[email protected] ~]# rpm -e –nodeps tzdata-java-2013g-1.el6.noarch

1.3
此時查詢java -version會出現錯誤，而查詢javac -version則沒有問題
[[email protected] ~]# java -version
-bash: /usr/bin/java: 沒有那個檔案或目錄
[[email protected] ~]# javac -version
javac 1.6.0_45

1.4
此時執行source命令讓之前配置過jdk環境的profile檔案再次生效
[[email protected] ~]# source /etc/profile

1.5
此時即可看到成功了
[[email protected] ~]# java -version
java version “1.6.0_45”
Java(TM) SE Runtime Environment (build 1.6.0_45-b06)
Java HotSpot(TM) 64-Bit Server VM (build 20.45-b01, mixed mode)
[[email protected] ~]# javac -version
javac 1.6.0_45

linux安裝jdk後發現系統帶有openjdk的處理