Update openjdk version

Author: pierlauro

.travis.yml

@@ -2,7 +2,7 @@ language: java
 before_install: ./ant_ivy_bootstrap.sh
 env: PATH="$HOME/.ant/home/bin:$PATH"
 install: ant ivy-setupjars
-jdk: oraclejdk8
+jdk: oraclejdk11
 cache:
   directories:
     - $HOME/jars