查看操作系统版本 
uname -a

cat /etc/redhat-release 

sudo yum search java | grep openjdk

sudo yum install java-1.8.0-openjdk.x86_64

sudo yum install java-11-openjdk.x86_64


java 
java -version 
java -verbose 


which java
/usr/bin/java
ls -al /usr/bin |grep java
lrwxrwxrwx   1 root root           22 12月 26 18:20 java -> /etc/alternatives/java

选择jdk 
sudo alternatives --config java

共有 2 个提供“java”的程序。

  选项    命令
-----------------------------------------------
*+ 1           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.292.b10-9.oe1.x86_64/jre/bin/java)
   2           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.12.9-1.oe1.x86_64/bin/java)

按 Enter 保留当前选项[+]，或者键入选项编号：

选择2 

java -version
openjdk version "11.0.12" 2021-07-20
OpenJDK Runtime Environment Bisheng (build 11.0.12+9)
OpenJDK 64-Bit Server VM Bisheng (build 11.0.12+9, mixed mode, sharing)