update to JDK 11

[alee]

Oracle licensing has become increasingly predatory. We may need to migrate / reimplement this entire framework in a more OSS friendly language at some point.

https://www.oracle.com/technetwork/java/java-se-support-roadmap.html

[alee]

https://medium.com/@javachampions/java-is-still-free-2-0-0-6b9aa8d6d244