On macOS, we can add another JVM while having old versions of the JVM still installed.
How do I point IntelliJ 2017.2 to another version of my JVM?
I can find no such setting in the Preferences window.
Preferences > Build, Execution, Deployment – Nope.
Preferences > Build, Execution, Deployment > Compiler – Nope.
Preferences > Build, Execution, Deployment > Compiler > Java Compiler – Nope.
On
Don't know for Mac. However, since IntelliJ is platform independant, I guess it will be in the same location. Go to File > Other settings > default project structure for a global change or File > Project Structure for a project dependant change. Under project SDK you can find the SDK in use, with the New button you can choose another one. Default will be the newest version if you have not yet a project created.
On the welcome screen before creating a project you can go to Configure at the bottom, Project Default > Project Structure to define the default JDK you want to use. Then hit the new button to choose a not listed JDK and locate it yourself.
If you don't have a project, you can access the dialog with SDK configuration from the Welcome Screen:
Configure|Project Defaults|Project Structure| SDKs.However, IDE will ask for the SDK anyway when you add a new project, so there is not much sense in defining it beforehand.