move to oraclejdk9 unless will switched to new since version

Haehnchen · Haehnchen · commit 4d3a79623e8d · 2019-08-03T12:33:24.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,7 +1,7 @@
 sudo: false
 language: java
 jdk:
-  - oraclejdk8
+  - oraclejdk9
   - oraclejdk11
 
 before_cache:
