Use pre-existing JDK installations

[sebthom]

I would like to use vfox on github action runners in a way that in case a JDK is already installed vfox does not download the JDK again but the pre-installed one can be registered into vfox.

I would like to be able to do something like this:

# in a initial step I search for installed JDKs and register them with vfox
vfox register java@11-tem /opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/11.0.27-6
vfox register java@21-tem /opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/21.0.3

# in later steps I want to call `vfox install java` via some external bash script like this:
vfox install java@11-tem  # should be a no-op since already installed
vfox install java@21-tem  # should be a no-op since already installed
 # query the install dirs of multiple JDKs so I can reference them in Maven's toolchains.xml
JAVA_11_HOME=$(vfox home java@11-tem) 
JAVA_21_HOME=$(vfox home java@21-tem) 

Is this already possible somehow? If not could something like this be added?

[yeroc]

I'm also wondering whether this is possible. Not just for Github runners, but on my workstation as well. I already have system-packaged Java SDKs installed and would like vfox to either auto-detect and use them or at least allow me to manually register them.