【Centos7】卸載OpenJDK

通常狀況下，centos會自帶OpenJDK，Hadoop的運行環境要求本身配置JRE，但在home下配置好了JRE後，使用java -version仍然看到OpenJDK，緣由是系統根據$PATH路徑，首先會在/usr/bin/中找到OpenJDK的java，並不是咱們本身配置的JDK。

解決辦法有兩種：1.配置/etc/profile使/home/xxx/jdk/bin首先被找到。2.卸載OpenJDK

這裏推薦第二種

1.查看安裝了哪些OpenJDK

sudo rpm -qa | grep jdk

2.卸載OpenJDK

sudo yum -y remove java-1.8.0-open*

3.這時在/usr/bin中已經沒有java了

 

4.使用java -version看到了本身配置的JDK，這裏已經成功卸載

[hadoop@master1 ~]$ java -version
java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)

5.這一步能夠不看了，僅僅是經過卸載記錄來研究OpenJDK的RPM包依賴關係

[oracle@hadoop ~]$ yum -y remove java-1.8.0-openjdk*
Loaded plugins: fastestmirror
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
You need to be root to perform this command.
[oracle@hadoop ~]$ su
Password: 
[root@hadoop oracle]# yum -y remove java-1.8.0-openjdk*
Loaded plugins: fastestmirror
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
Resolving Dependencies
--> Running transaction check
---> Package java-1.8.0-openjdk-headless.x86_64 1:1.8.0.111-2.b15.el7_3 will be erased
--> Processing Dependency: java-headless >= 1:1.6 for package: 1:libreoffice-core-5.0.6.2-3.el7.x86_64
---> Package unoconv.noarch 0:0.6-7.el7 will be erased
--> Finished Dependency Resolution

Dependencies Resolved

================================================================================
 Package                      Arch    Version                   Repository
                                                                           Size
================================================================================
Removing:
 java-1.8.0-openjdk-headless  x86_64  1:1.8.0.111-2.b15.el7_3   @updates  102 M
Removing for dependencies:
 libreoffice-calc             x86_64  1:5.0.6.2-3.el7           @base      29 M
 unoconv                      noarch  0.6-7.el7                 @base     196 k

Transaction Summary
================================================================================
Remove  1 Package (+10 Dependent packages)

Installed size: 402 M
Downloading packages:
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Erasing    : unoconv-0.6-7.el7.noarch                                    1/11 
  Erasing    : 1:java-1.8.0-openjdk-headless-1.8.0.111-2.b15.el7_3.x86_   11/11 
failed to read link /usr/bin/java: No such file or directory
  Verifying  : 1:libreoffice-writer-5.0.6.2-3.el7.x86_64                   1/11 
  Verifying  : 1:libreoffice-impress-5.0.6.2-3.el7.x86_64                  2/11 
  Verifying  : 1:libreoffice-pdfimport-5.0.6.2-3.el7.x86_64                3/11 
Removed:
  java-1.8.0-openjdk-headless.x86_64 1:1.8.0.111-2.b15.el7_3                    
Dependency Removed:
  libreoffice-calc.x86_64 1:5.0.6.2-3.el7                                                                          
  unoconv.noarch 0:0.6-7.el7                                                    

Complete!
[root@hadoop oracle]# 

經過記錄能夠看出 libreoffice這個軟件是基於JAVA的，卸載OpenJDK後，libreoffice就不能用了，節省了402M的磁盤空間。