[oe] Support for OpenJDK 9+

[chris.laplante at agilent.com]

> >> We recently got a request to add support for Java(OpenJdk) 9+.
> >> I came to wonder if there was any limitations preventing the use of
> >> Openjdk 9+ on arm?
> 
> None that I'm aware of...

I have a somewhat related question. Is there a technical reason that we're still using GNU Classpath? That project looks to be thoroughly abandoned since 2012. As you may have seen last night I submitted some patches to fix some "simple" bugs in BigDecimal. By "simple", I mean the kind of bug that I'd expect to bite many users, as opposed to an esoteric or corner-case bug. 

If it's just that no one has ever volunteered to move to something newer, then I may be able to help. No commitments yet though.  

Thanks,
Chris