anchor.diff:  FROM ubuntu:focal
   
   ARG DEBIAN_FRONTEND noninteractive
  +ENV DEBIAN_FRONTEND noninteractive
   
   # Use specific Java version
   ARG JAVA_VERSION 11.0.11.hs-adpt
  
positive.code:     apt-utils \
      ca-certificates
  
  # Enforce https-only Ubuntu apt repositories 
  # RUN sed -i 's|http://archive.ubuntu.com/ubuntu|https://mirrors.kernel.org/ubuntu|g' /etc/apt/sources.list
  
  # Install support for managing locales
  
negative.code: RUN bash -c 'source ${SDKMAN_DIR}/bin/sdkman-init.sh && sdk install java ${JAVA_VERSION}'
  
  # Configure R Java home
  RUN bash -c 'source ${SDKMAN_DIR}/bin/sdkman-init.sh && R CMD javareconf'
  
  # Cleanup
  RUN apt-get -y clean
  