I am building a Docker image with the below file. It is a simple Spring Boot app.
When I make an update to the Spring project, I am rebuilding the image to get the updated image. However, this is creating an entirely new image that is getting completely re-pushed up to the repo in it's entirety (700+MB). How do I update an existing image to include the newly updated jar instead of a completely new image so that I don't have to push up 700+MB just to update the Spring app?

This is the dockerfile I am currently using:

```
FROM java:8
EXPOSE 8080
VOLUME /tmp
ADD app-name.1.0.jar app.jar
RUN bash -c 'touch /app.jar'
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","app.jar"]

```

*Note:* When I run the **docker attach** command, it just sits there and does nothing.