Multi release jars on boot classpath

[Michael Rasmussen]

> Aside from it being an uncommon way to
> deploy a library in the past, the additional challenge now is that many
> non-core modules are no longer defined to the boot loader and so not all
> libraries can be deployed with -Xbootclasspath/a anyway.

I can only say that I'm disappointed that the null-classloader will be
excluded from this JEP, as I do consider it one of the standard class
loaders in the JRE, which is defined as a goal for the JEP.

As for being an uncommon way to deploy libraries, I do think it's
common for java agents to either add themselves via entry in the
manifest, or have their premain class add the jar via Instrumentation
API, as this is the only way if you want to instrument classes loaded
with the null-classloader to call into your code.

but guess I'll have to litter my agent code with if (isJDK9()) check
to conditionally load classes for supporting Module etc.

/Michael