From Bitpost wiki
Install Oracle JDK 9 (considered stable in 3/2018)
su - add-apt-repository ppa:webupd8team/java apt-get update apt-get install oracle-java9-installer emacs /etc/environment JAVA_HOME="/usr/lib/jvm/java-9-oracle"
There was reorganization of some xml parsers from/to EE, from what I was told, so you might need to stick with Java 8:
apt-get install oracle-java8-installer