How to change the default Java version on CentOS 7

• How to switch to openjdk-11

[lwk@qwfys ~]$ sudo alternatives --config java
[sudo] password for lwk: 

There are 4 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
   1           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.fc32.x86_64-slowdebug/bin/java)
 + 2           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.fc32.x86_64/bin/java)
*  3           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.252.b09-1.fc32.x86_64/jre/bin/java)
   4           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.252.b09-1.fc32.x86_64-slowdebug/jre/bin/java)

Enter to keep the current selection[+], or type selection number: 2
[lwk@qwfys ~]$ sudo alternatives --config javac

There are 4 programs which provide 'javac'.

  Selection    Command
-----------------------------------------------
   1           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.fc32.x86_64-slowdebug/bin/javac)
 + 2           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.fc32.x86_64/bin/javac)
*  3           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.252.b09-1.fc32.x86_64/bin/javac)
   4           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.252.b09-1.fc32.x86_64-slowdebug/bin/javac)

Enter to keep the current selection[+], or type selection number: 2
[lwk@qwfys ~]$ 

edit ~/.bashrc,then append the flow codes:

export JAVA_HOME=$(dirname $(dirname $(readlink $(readlink $(which javac)))))

run the flow command

source ~/.bashrc

Reference

• Set JAVA_HOME on CentOS / RHEL / Fedora