chore: revert to oraclejdk8
chore: revert to oraclejdk8

Travis CI environment provides Oracle JDK 7 (default), Oracle JDK 8, OpenJDK 6, OpenJDK 7, Gradle 2.0, Maven 3.2 and Ant 1.8.

[http://docs.travis-ci.com/user/languages/java/]

Orange-OpenSource/elpaaso-plugins-management