.travis.yml in pubnub-4.1.5 vs .travis.yml in pubnub-4.1.6

- old
+ new

@@ -21,7 +21,7 @@
 
 matrix:
   include:
     - rvm: jruby-head
       env: JRUBY_OPTS="--server -J-Xms1500m -J-Xmx1500m -J-XX:+UseConcMarkSweepGC -J-XX:-UseGCOverheadLimit -J-XX:+CMSClassUnloadingEnabled"
-      jdk: oraclejdk8
+      jdk: oraclejdk9
 