I think there are multiple complementary paths of resolution here. One is to implement in p2 the proposal in https://bugs.eclipse.org/bugs/show_bug.cgi?id=387701#c0
and could even be extended wider to simply not make a product IU have a requirement on a recent JavaSE version after all since the product typically can boot with any JavaSE and the actual required version is defined by transitive dependencies. Another path could be to have Tycho reusing (config.)a.jre.javase from the target-platform definition instead of regenerating a different IU. I'd like to try to implement both.
I've got a basic question about this later one: why does Tycho not consume the existing (config.)a.jre.javase IUs? Is this necessary? Would it make sense to implement a strategy preferring reuse of those existing ius?
Thanks in advance for your insights.