anchor.diff:  # Install Maven
   ARG MAVEN_VERSION=3.3.9
   ARG USER_HOME_DIR="/root"
  -ENV MAVEN_CONFIG "$USER_HOME_DIR/.m2"
  -ENV MAVEN_HOME /usr/share/maven
  -ENV JENKINS_MAVEN_CONFIG "$MAVEN_HOME/conf"
  +ENV MAVEN_CONFIG "$USER_HOME_DIR/.m2" \
  +    MAVEN_HOME /usr/share/maven \
  +    JENKINS_MAVEN_CONFIG "$MAVEN_HOME/conf"
   
   RUN mkdir -p /usr/share/maven /usr/share/maven/ref $MAVEN_CONFIG \
     && curl -fsSL http://apache.osuosl.org/maven/maven-3/$MAVEN_VERSION/binaries/apache-maven-$MAVEN_VERSION-bin.tar.gz \
  
positive.code: # or config file with your custom jenkins Docker image.
  RUN mkdir -p /usr/share/jenkins/ref/init.groovy.d
  
  ENV TINI_VERSION 0.10.0
  ENV TINI_SHA 7d00da20acc5c3eb21d959733917f6672b57dabb
  
  # Use tini as subreaper in Docker container to adopt zombie processes
  RUN curl -fsSL https://github.com/krallin/tini/releases/download/v${TINI_VERSION}/tini-static -o /bin/tini && chmod +x /bin/tini \
  
negative.code: ENV REFRESHED_AT 2016-09-09
  
  # Runtime environment settings
  ENV JENKINS_HOME /var/jenkins_home \
      JENKINS_SLAVE_AGENT_PORT 50000
  
  # Build arguments setting
  ARG user=jenkins
  