Merge pull request #122 from marschall/build-with-openjdk11

Switch build to OpenJDK 11

Author: keilw

.travis.yml

@@ -1,10 +1,6 @@
 language: java
 jdk:
-  - oraclejdk9
-addons:
-  apt:
-    packages:
-      - oracle-java9-installer
+  - openjdk11
 
 after_success:
   - mvn deploy -Dmaven.test.skip -DcreateDocs=true -s settings.xml