anchor.diff:  
   WORKDIR /root
   
  -# Install the most recent version of Java8
  -RUN apt-get update && apt-get -y install openjdk-8-jdk openjdk-8-jre-headless
  -
   # Add Zulu repository for Java7
   # Instructions from https://docs.azul.com/zulu/zuludocs/#ZuluUserGuide/PrepareZuluPlatform/AttachAPTRepositoryUbuntuOrDebianSys.htm
   RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0xB1998361219BD9C9
  
positive.code:   rm apache-maven-3.6.2-bin.tar.gz
  
  # ci.xwiki.org expects:
  # - Java to be available at /home/hudsonagent/java8
  # - Java7 to be available at /home/hudsonagent/java7
  # - Maven to be available at /home/hudsonagent/maven
  RUN mkdir -p /home/hudsonagent && \
   ln -fs /usr/lib/jvm/java-8-openjdk-amd64 /home/hudsonagent/java8 && \
   ln -fs /usr/lib/jvm/zulu-7-amd64 /home/hudsonagent/java7 && \
   ln -fs /home/hudsonagent/java8 /home/hudsonagent/java && \
   ln -fs /home/hudsonagent/java/bin/java /usr/bin/java && \
  
negative.code: #   |____||____|     \/  \/    [___][__|  \_][___]
  
  MAINTAINER XWiki Development Teeam <committers@xwiki.org>
  
  # check that Java 8 is already installed by:
  # 1. checking if the JAVA_HOME is set
  # 2. checking that the version of Java is openjdk
  # 3. checking that the actual version installed is an 1.8.0 (we allow the build to be upgraded)
  # We perform those checks very early to have a fail fast, since it all depends on the parent image.
  RUN test ! -z $JAVA_HOME && $JAVA_HOME/bin/java -version 2>&1 | grep "OpenJDK" | grep "build 1.8.0"
  
  # Install VNC + Docker CE + lsof (to list open ports for debugging reasons)
  RUN apt-get update && \
  