* Add oraclejdk9 to .travis.yml

* Upgrade maven-compiler-plugin

* Exclude jdk.tools from hadoop dependency

[core] Fixing squid:S1319 -  Declarations should use Java collection interfaces such as "List" rather than specific implementation classes such as "LinkedList".
(manolama - updated bindings added since the PR)

Signed-off-by: Chris Larsen <clarsen@yahoo-inc.com>