Putting a fat jar into a Docker container is a waste of storage, bandwidth and time. Fortunately, we can leverage Docker’s image layering and registry caching to create incremental builds and very small artifacts. For instance, we could reduce the effective size of new artifacts from 75 MB to only one MB! And the best is that there is a plugin for Maven and Gradle handling everything for us.

During development, it’s important to have fast feedback loops after code changes. Waiting for a cold restart of the application is not satisfying at all and slows down the development process. In this post, I show how we can reduce the turnaround time by using certain JVM arguments and class reloading. Besides those framework-independent means, I’ll give some tips for Vaadin and Spring Boot applications.