To switch between different versions of Java on your Mac, you can use the jenv tool in combination with Homebrew. Here’s a step-by-step guide:

1 - Install jenv using Homebrew by running the following command in Terminal:

$ brew install jenv

2 - Once the installation is complete, you need to initialize jenv. Run the following command to add jenv to your shell:

$ echo 'eval "$(jenv init -)"' >> ~/.bash_profile

If you’re using a different shell (such as Zsh), replace ~/.bash_profile with the appropriate configuration file (e.g., ~/.zshrc).

3 - Restart your Terminal or run the following command to apply the changes:

$ source ~/.bash_profile

4 - Now, you can install different versions of Java using Homebrew. For example, to install AdoptOpenJDK version 11, run:

$ brew install --cask adoptopenjdk@11

You can install multiple versions of Java using this command.

5 - After installing different Java versions, you need to let jenv know about them. Run the following command for each installed version:

$ jenv add /Library/Java/JavaVirtualMachines/adoptopenjdk-11.jdk/Contents/Home

Replace the path with the correct path to the Java installation directory of each version.

6 - To see the list of installed Java versions, run:

$ jenv versions

You should see a list of installed Java versions.

7 - Set a global Java version using jenv by running the following command:

$ jenv global 11.0

Replace 11.0 with the version number you want to set as the default.

8 - To verify the currently active Java version, run:

$ java -version

The displayed version should match the one you set using jenv.

That’s it! You have successfully switched between different versions of Java using jenv. You can set a different version as the default or configure Java version per directory using jenv local command. Refer to the jenv documentation for more information on advanced usage and configuration options.