Managing Multiple Java Versions on Mac OS X

Installing multiple Java versions on Mac OS X can be a challenge due to the way Java manages its installations. However, there is a solution that allows you to easily install and manage different Java versions: Homebrew.

Using Homebrew and jenv

Homebrew is a package manager that simplifies the installation and management of software on Mac OS X. To use Homebrew to manage multiple Java versions, you will also need to install jenv, a Java version manager.

Installation Steps

1. Install Homebrew:

   /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

2. Install Homebrew jenv:

   brew install jenv

3. Install Homebrew-cask:

   brew install caskroom/cask/homebrew-cask

4. Install a specific Java version using cask:

   brew install --cask temurin9

5. Add this version to jenv to manage it:

   jenv add /Library/Java/JavaVirtualMachines/temurin-java9.jdk/Contents/Home

6. Repeat steps 4-6 for each version of Java you need.

Important Notes

• Check the paths of the installed versions using: /usr/libexec/java_home -V
• Built-in JRE default path: /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin/Contents/Home
• Apple-downloaded JDKs path: /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/
• Oracle-downloaded JDKs path: /Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/Home

Resources

• [Removing Java 8 JDK from Mac](https://apple.stackexchange.com/questions/174783/how-to-completely-remove-java-8-from-mac)
• [Installing Java 8 and Managing Multiple Versions](http://hanxue-it.blogspot.ch/2014/05/installing-java-8-managing-multiple.html)
• [Mac OS X Setup Guide](http://sourabhbajaj.com/mac-setup/)
• [Homebrew](http://brew.sh/)
• [Homebrew Documentation](https://github.com/Homebrew/homebrew/tree/master/share/doc/homebrew#readme)
• [Homebrew Homebrew-versions](https://github.com/Homebrew/homebrew-versions)
• [Homebrew-cask](https://github.com/caskroom/homebrew-cask)
• [jenv](http://www.jenv.be/)