Updated the travis JDK version to OpenJDK11. Java 1.8 now requires a special license in order to use in production, so it's probably safe to eliminate full support for it. The issues that exist in Java 1.8 are only relevant to relative values that have upper case characters.

Author: Jake Waffle

.travis.yml

@@ -5,4 +5,4 @@ cache:
    - $HOME/.m2
 
 jdk:
-   - oraclejdk8
+   - openjdk11