travis config: dist:xenial and language:java (#77)

diff --git a/.travis.yml b/.travis.yml
index 7815908..2a5606b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,10 +16,9 @@
 #
 
 sudo: required
-group: deprecated-2017Q3
-language: scala
-scala:
-  - 2.12.7
+dist: xenial
+jdk: openjdk8
+language: java
 services:
   - docker