安装 jre

		
[root@localhost ~]# dnf install java-latest-openjdk		
		
		

安装 jdk

		
[root@localhost ~]# dnf install java-latest-openjdk-devel
		
		

默认是 jdk1.8，使用 alternatives 切换 java 默认版本为 java 14

		
[root@localhost ~]# java -version
openjdk version "1.8.0_262"
OpenJDK Runtime Environment (build 1.8.0_262-b10)
OpenJDK 64-Bit Server VM (build 25.262-b10, mixed mode)


[root@localhost ~]# alternatives --config java

There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
   1           java-latest-openjdk.x86_64 (/usr/lib/jvm/java-14-openjdk-14.0.2.12-1.rolling.el8.x86_64/bin/java)
*+ 2           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.262.b10-0.el8_2.x86_64/jre/bin/java)

Enter to keep the current selection[+], or type selection number: 1


[root@localhost ~]# java -version
openjdk version "14.0.2" 2020-07-14
OpenJDK Runtime Environment 20.3 (build 14.0.2+12)
OpenJDK 64-Bit Server VM 20.3 (build 14.0.2+12, mixed mode, sharing)