Multiple JVM versions on macOS
It’s pretty common when doing Java development to need mutiple versions installed alongside each other. With Brew and Jenv, switching Java versions between projects becomes easy.
Set up the versions cask
First you need to tap the
$ brew tap caskroom/versions
Now you can see multiple versions of the Java cask:
Install desired Java versions
Now we have the
versions cask, we can install our desired version of Java, e.g.:
$ brew cask install java8
At this point, you can not easily switch between the different Java versions, and the most recent Java version will be used.
Install and set up Jenv
Jenv allows you to manage the environment for multiple Java installs, and works well with Brew’s managed versions of Java.
$ brew install jenv
To enable the Jenv shims and autocompletion:
$ echo 'if which jenv > /dev/null; then eval "$(jenv init -)"; fi' >> ~/.bash_profile
Now restart your shell by either re-opening Terminal, or running the following:
$ exec $SHELL -l
Add JVMs to Jenv
Add your JVMs to Jenv as follows:
$ jenv add /Library/Java/JavaVirtualMachines/jdk-9.0.4.jdk/Contents/Home/ $ jenv add /Library/Java/JavaVirtualMachines/jdk1.8.0_162.jdk/Contents/Home/
By default, Jenv will be using the system installed version of Java, which will be the latest one.
You can override this globally by running:
$ jenv global oracle64-22.214.171.124
or if you just want to affect a particular project:
$ jenv local oracle64-126.96.36.199
Check it works
$ java -version
Enable Maven shim
If you’re using Maven on the CLI, you will want to enable the Maven shim, otherwise it will still be using the system version of Java:
$ jenv enable-plugin maven
See the Jenv site for more details.