Make it possible to have multiple JDKs installed of the same version #46
Description
Right now you can have only a single JDK installed of a certain version. That's nicely simple but very restrictive. If I want to have a GraalVM JDK installed for example it currently is impossible to have a "normal" JDK installed of the same version.
It should simply be possible to install any number of JDKs of the same (major) version.
Some system will have to be determined that selects which version to use at any given time.
This will use the feature, which is already implemented but currently unused, where you can select the exact JDK that you want to use by supplying the JDK's id instead of only the major version. (Would be usable for --java but not for //JAVA!)