Install multiple Java versions and switch between them on macOS and Ubuntu

macOS

Simplest would be to installed with Homebrew:

1# /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
2📋
3brew install openjdk # installs openjdk@18

Alternatively, you can download the tarball from here: https://jdk.java.net/16/ and extract it to /Library/Java/JavaVirtualMachines/

1sudo mv openjdk-16.0.1_osx-x64_bin.tar.gz /Library/Java/JavaVirtualMachines/
2cd /Library/Java/JavaVirtualMachines/
3sudo tar -xzf openjdk-16.0.1_osx-x64_bin.tar.gz
4sudo rm openjdk-16.0.1_osx-x64_bin.tar.gz

Update $PATH

1echo -n "\nexport JAVA_HOME=`/usr/libexec/java_home -v16`" >> ~/.zprofile
2
3source ~/.zprofile

Confirm install

1java -version

openjdk version "16.0.1" 2021-04-20
OpenJDK Runtime Environment (build 16.0.1+9-24)
OpenJDK 64-Bit Server VM (build 16.0.1+9-24, mixed mode, sharing)

/usr/libexec/java_home -v16 gives you the version specific path. If you wanted to use a different JDK version, say 17, then you’d update JAVA_HOME and set it to /usr/libexec/java_home -v17

Ubuntu Linux

1# java -version
2
3openjdk version "1.8.0_312"
4OpenJDK Runtime Environment (build 1.8.0_312-8u312-b07-0ubuntu1~20.04-b07)
5OpenJDK 64-Bit Server VM (build 25.312-b07, mixed mode)

1sudo apt install -y openjdk-17-jdk
2
3update-java-alternatives --list

java-1.11.0-openjdk-amd64      1111       /usr/lib/jvm/java-1.11.0-openjdk-amd64
java-1.17.0-openjdk-amd64      1711       /usr/lib/jvm/java-1.17.0-openjdk-amd64
java-1.18.0-openjdk-amd64      1811       /usr/lib/jvm/java-1.18.0-openjdk-amd64
java-1.8.0-openjdk-amd64       1081       /usr/lib/jvm/java-1.8.0-openjdk-amd64

1# sudo update-java-alternatives --set /path/to/java/version
2sudo update-java-alternatives --set /usr/lib/jvm/java-1.17.0-openjdk-amd64

Check version with java -version and you’ll see the new one

openjdk version "17.0.2" 2022-01-18
OpenJDK Runtime Environment (build 17.0.2+8-Ubuntu-120.04)
OpenJDK 64-Bit Server VM (build 17.0.2+8-Ubuntu-120.04, mixed mode, sharing)

Update the $JAVA_HOME env var

1# export JAVA_HOME="$(jrunscript -e 'java.lang.System.out.println(java.lang.System.getProperty("java.home"));')"
2export JAVA_HOME='/usr/lib/jvm/java-1.17.0-openjdk-amd64'