anchor.diff:  COPY src src
   
   # and build (in multiple steps steps to try to reuse the lengthy maven download)
  -RUN echo 'Using maven options ${MAVEN_OPTS}'
  -RUN /usr/bin/mvn compile ${MAVEN_OPTS}
  +RUN /usr/bin/mvn compile
   # copy cached node modules before the package
   RUN cp -r /cache/node_modules /src/main/angular/node_modules
  -RUN /usr/bin/mvn test package ${MAVEN_OPTS}
  +RUN /usr/bin/mvn test package
   RUN echo 'build finished'
   
   
  
positive.code: 
  # variables build stage
  ARG MAVEN_URL=https://downloads.apache.org/maven/maven-3/3.6.3/binaries/apache-maven-3.6.3-bin.tar.gz
  ARG MAVEN_OPTS=
  ARG MAVEN_HOME=/usr/share/maven
  
  # install dependencies (bash to launch angular build, ncurses for pretty output with tput, git for npm deps)
  
negative.code: 
  # we add the pom and validate the project (does nothing), but some of the downloads will be cached
  # and this layer will not be built unless the pom is changed
  COPY pom.xml pom.xml
  RUN /usr/bin/mvn dependency:go-offline
  
  # cache some node stuff to speed up builds
  COPY src/main/angular/*.json /cache/
  