Change JAVA version

I was having Java 25, but I need to switch to Java 17

Check current versions

java -version
javac -version

Output: Java 25

Update and Install Java 17

sudo apt update
sudo apt install openjdk-17-jdk

verify it installed

ls /usr/lib/jvm

Output: java-17-openjdk-amd64 java-25-openjdk-amd64

Switch Java to 17

For Java

sudo update-alternatives --config java

For Javac

sudo update-alternatives --config javac

Output: Options to select the new Java version

Select and follow on screen prompts

verify

java -version
javac -version

Now it should be Java 17

Optional cleanup

sudo apt remove openjdk-25-jdk openjdk-25-jre
sudo apt autoremove

Quick final check

java -version && javac -version && echo $JAVA_HOME