In a world of DevOps, agile software development practices, the introduction of microservices, and with more and more teams doing continuous development and deployment, it becomes even more important to be able to quickly see the code changes to an application without going through the whole process of re-compiling the entire project, rebuilding, and restarting the application.

The arrival of containerization services such as Docker has also presented a challenge in terms of access to the actual application running environment. It has changed the notion of a machine by abstracting and encapsulating the runtime environment, removing the ability to use any port to get access.

Spring Boot DevTools provides the ability to do selective class reloading and debugging applications running inside Docker containers using HTTP remote debug tunnel, in order to give developers a quick feedback loop to see their changes reflected in the running application without long rebuild and restart cycles.