Move from jdk9 to jdk11

4 jobs from master in 3 minutes and 40 seconds
Status Job ID Name Coverage
  Build
passed #138717798
linkchecker

00:01:09

passed #138717797
maven-jdk11

00:03:40

passed #138717796
maven-jdk8

00:02:46

passed #138717799
pa11y

00:01:39