build: replace jabba by proper debian installation

.travis.yml

@@ -11,16 +11,17 @@ git:
 before_install:
   # make comparing to origin/master work
   - git remote set-branches --add origin master && git fetch
-  # using jabba for custom jdk management
-  - curl -sL https://raw.githubusercontent.com/shyiko/jabba/0.11.1/install.sh | bash && . ~/.jabba/jabba.sh
-  - jabba install [email protected]
-  - jabba use "[email protected]"
   - java -version
 
 addons:
   apt:
+    sources:
+    # Official debian package for AdoptOpenJDK from https://adoptopenjdk.net/installation.html#linux-pkg
+    - sourceline: deb https://adoptopenjdk.jfrog.io/adoptopenjdk/deb/ xenial main
+      key_url: https://adoptopenjdk.jfrog.io/adoptopenjdk/api/gpg/key/public
     packages:
-    - graphviz
+      - graphviz
+      - adoptopenjdk-8-hotspot
 
 before_cache:
   - find $HOME/.ivy2 -name "ivydata-*.properties" -print -delete
@@ -30,7 +31,6 @@ cache:
   directories:
     - $HOME/.ivy2/cache
     - $HOME/.sbt/boot
-    - $HOME/.jabba/jdk
     - $HOME/.cache/coursier
 
 script: