anchor.diff:  # Install Maven
   ARG MAVEN_VERSION=3.3.9
   ARG USER_HOME_DIR="/root"
  -ENV MAVEN_CONFIG "$USER_HOME_DIR/.m2" \
  -    MAVEN_HOME /usr/share/maven \
  -    JENKINS_MAVEN_CONFIG "$MAVEN_HOME/conf"
  +ENV MAVEN_CONFIG "$USER_HOME_DIR/.m2"
  +ENV MAVEN_HOME /usr/share/maven
  +ENV JENKINS_MAVEN_CONFIG "$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-$MAVEN_VERSION-bin.tar.gz \
  -    | tar -xzC /usr/share/maven --strip-components=1 \
  -  && ln -s /usr/share/maven/bin/mvn /usr/bin/mvn
  +    && curl -fsSL http://apache.osuosl.org/maven/maven-3/$MAVEN_VERSION/binaries/apache-maven-$MAVEN_VERSION-bin.tar.gz \
  +       | tar -xzC /usr/share/maven --strip-components=1 \
  +    && ln -s /usr/share/maven/bin/mvn /usr/bin/mvn
   
   COPY mvn-entrypoint.sh /usr/local/bin/mvn-entrypoint.sh
   COPY mvn-settings-docker.xml $MAVEN_CONFIG/settings.xml
   RUN /usr/local/bin/mvn-entrypoint.sh \
  -  && cp -f $MAVEN_CONFIG/settings.xml $JENKINS_MAVEN_CONFIG/settings.xml \
  -  && chown -R ${user} "$MAVEN_HOME"
  +    && cp -f $MAVEN_CONFIG/settings.xml $JENKINS_MAVEN_CONFIG/settings.xml \
  +    && chown -R ${user} "$MAVEN_HOME"
   
   # for main web interface:
   EXPOSE 8080
  
positive.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
  
negative.code: # could use ADD but this one does not check Last-Modified header neither does it allow to control checksum
  # see https://github.com/docker/docker/issues/8331
  RUN curl -fsSL ${JENKINS_URL} -o /usr/share/jenkins/jenkins.war \
      && echo "${JENKINS_SHA}  /usr/share/jenkins/jenkins.war" | sha1sum -c -
  
  ENV JENKINS_UC https://updates.jenkins.io
  RUN chown -R ${user} "$JENKINS_HOME" /usr/share/jenkins/ref
  