anchor.diff:  	&& [ "$JAVA_HOME" = "$(docker-java-home)" ]
   
   RUN /var/lib/dpkg/info/ca-certificates-java.postinst configure
  -____
  -
  -If you read again the Dockerfile from bottom to top, you'll match every command with a layer.
  -We could continue again with the https://github.com/docker-library/buildpack-deps/blob/1845b3f918f69b4c97912b0d4d68a5658458e84f/jessie/scm/Dockerfile[buildpack-deps:jessie-scm Dockerfile] but I guess you get the point.
  -
  -IMPORTANT
  +----
  +
  +If you read the Dockerfile from bottom to top, you'll match every command with a layer.
  +We could continue again with the https://github.com/docker-library/buildpack-deps/blob/1845b3f918f69b4c97912b0d4d68a5658458e84f/jessie/scm/Dockerfile[Dockerfile of the next base image (buildpack-deps:jessie-scm)] but I guess you get the point.
  +
  +[IMPORTANT]
   ----
   A Docker image is a stack of layers.
   When you build on top of a base image, you are stacking layers on top of all the layers of the base image.
  
positive.code: Status: Downloaded newer image for maven:3.3.9-jdk-8
  ----
  
  The output of the `docker pull` shows you all the images that the maven:3.3.9-jdk-8 image is made of.
  If you compare this output to the output of the `docker history` command, you will notice that we have 11 lines here for 24 layers in the image.
  This is due to the fact that during the build process, docker is able to make optimizations by squashing layers into an image.
  
  IMPORTANT
  ----
  The previous statement is right since Docker 1.10.
  Before this, there was a 1:1 ratio between images and layers.
  ----
  
  Of course this does not change anything regarding what you download.
  
negative.code: 
  [source]
  ----
  openjdk:8-jdk: Pulling from library/openjdk
  
  386a066cd84a: Already exists
  75ea84187083: Already exists
  