安装 Java 1.8 JRE

		
dnf install java-1.8.0-openjdk		
		
		

安装 Java 1.8 JDK

		
dnf install java-1.8.0-openjdk-devel		
		
		

当我们安装 maven 的时候会自动安装 Java 11，需要使用下面方法切换默认Java版本

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

There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
   1           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.342.b07-1.el9_0.x86_64/jre/bin/java)
*+ 2           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.16.0.8-1.el9_0.x86_64/bin/java)

Enter to keep the current selection[+], or type selection number: 1   
[root@cloud ~]# alternatives --config javac

There are 2 programs which provide 'javac'.

  Selection    Command
-----------------------------------------------
   1           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.342.b07-1.el9_0.x86_64/bin/javac)
*+ 2           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.16.0.8-1.el9_0.x86_64/bin/javac)

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

		
[root@cloud ~]# javac -version
javac 1.8.0_342

[root@cloud ~]# java -version
openjdk version "1.8.0_342"
OpenJDK Runtime Environment (build 1.8.0_342-b07)
OpenJDK 64-Bit Server VM (build 25.342-b07, mixed mode)