Mac

Install Java 11 with Homebrew:
brew install openjdk@11

Add it in your environment variable:
sudo ln -sfn /usr/local/opt/openjdk@11/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk-11.jdk

Switch manually:
To use Java 11:

export JAVA_HOME=$(/usr/libexec/java_home -v 11)
export PATH=$JAVA_HOME/bin:$PATH

Java 18:

export JAVA_HOME=$(/usr/libexec/java_home -v 18)
export PATH=$JAVA_HOME/bin:$PATH

If you are on Linux (Ubuntu/Debian)

Check your current Java version: java -version

Install OpenJDK 11:
sudo apt update
sudo apt install openjdk-11-jdk

Configure which Java version to use
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/java-18-openjdk-amd64/bin/java 2

Then choose which one to use:
sudo update-alternatives --config java

You’ll see a list like:

Choose 1 to select Java 11.