Description of problem: Can Java based cartridges be configure to use other JDK versions, that might be installed on a node with alternatives? [Idea]: allow marker files to select any one of the nodes listed alternative versions of Java.
I've converted proposal into a trello card as it is a non-trivial change. https://trello.com/c/xG8duyXd/173-support-additional-jdks-for-java-cartridges
This is a great use case for a downloadable cart. There is too much of a test issue with including all possible versions in the standard carts.
It should be noted that using /etc/alternatives/ you can change the behavior for all gears running on a particular node. If you install a 3rd party JDK and point /etc/alternatives to that then all gears will run that 3rd party JVM. Also, on a per application instance basis - you can override the JAVA_HOME to point to whatever binary you would like; however, this is a manual step and is not built into the RHC or Web Console.