OpenJDK 21 : Install

	Install OpenJDK 21.
[1]	If you need only JRE, Install only [java-21-openjdk] package, but if you need compiler, Install [java-21-openjdk-devel] package, too.

[root@dlp ~]#  dnf -y install java-21-openjdk java-21-openjdk-devel [root@dlp ~]#  cat > /etc/profile.d/java.sh <<'EOF' export JAVA_HOME=$(dirname $(dirname $(readlink $(readlink $(which java))))) export PATH=$PATH:$JAVA_HOME/bin EOF [root@dlp ~]#  source /etc/profile.d/java.sh [root@dlp ~]#  java --version openjdk 17.0.3 2022-04-19 LTS OpenJDK Runtime Environment 21.9 (build 17.0.3+7-LTS) OpenJDK 64-Bit Server VM 21.9 (build 17.0.3+7-LTS, mixed mode, sharing) # verify to create test program [root@dlp ~]# cat > java_test.java <<'EOF' class java_test { public static void main(String[] args) { System.out.println("Hello Java World !"); } } EOF [root@dlp ~]#  javac java_test.java [root@dlp ~]#  java java_test Hello Java World !

[2]	If you installed multiple version of Java from CentOS official repository, it's possible to switch them with [alternatives].

[root@dlp ~]#  alternatives --config java There are 2 programs which provide 'java'. Selection Command ----------------------------------------------- *+ 1 java-17-openjdk.x86_64 (/usr/lib/jvm/java-17-openjdk-17.0.13.0.11-4.el9.x86_64/bin/java) 2 java-21-openjdk.x86_64 (/usr/lib/jvm/java-21-openjdk-21.0.5.0.11-2.el9.x86_64/bin/java) Enter to keep the current selection[+], or type selection number: 2 [root@dlp ~]#  alternatives --config javac There are 2 programs which provide 'javac'. Selection Command ----------------------------------------------- *+ 1 java-17-openjdk.x86_64 (/usr/lib/jvm/java-17-openjdk-17.0.13.0.11-4.el9.x86_64/bin/javac) 2 java-21-openjdk.x86_64 (/usr/lib/jvm/java-21-openjdk-21.0.5.0.11-2.el9.x86_64/bin/javac) Enter to keep the current selection[+], or type selection number: 2 [root@dlp ~]#  java --version openjdk 21.0.5 2024-10-15 LTS OpenJDK Runtime Environment (Red_Hat-21.0.5.0.11-1) (build 21.0.5+11-LTS) OpenJDK 64-Bit Server VM (Red_Hat-21.0.5.0.11-1) (build 21.0.5+11-LTS, mixed mode, sharing) [root@dlp ~]#  javac --version javac 21.0.5