anchor.diff:  
   # do all in one step
   RUN apk upgrade --update && \
  -    apk add --update curl ca-certificates bash git && \
  +    apk add --update curl tar ca-certificates bash git && \
       for pkg in glibc-${GLIBC_VERSION} glibc-bin-${GLIBC_VERSION} glibc-i18n-${GLIBC_VERSION}; do curl -sSL https://github.com/andyshinn/alpine-pkg-glibc/releases/download/${GLIBC_VERSION}/${pkg}.apk -o /tmp/${pkg}.apk; done && \
       apk add --allow-untrusted /tmp/*.apk && \
       rm -v /tmp/*.apk && \
  
positive.code: COPY settings-docker.xml /usr/share/maven/ref/
  ADD pom.xml /maven/
  RUN cd /maven \
      && /usr/share/maven/bin/mvn install
  
  VOLUME "$USER_HOME_DIR/.m2"
  
  
negative.code: 
  RUN mkdir -p /usr/share/maven /usr/share/maven/ref \
      && 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
  
  ENV MAVEN_HOME /usr/share/maven
  