Take Control of Your Build: Spring Boot and Beyond with Mill

• Vasilis Nicolaou (Vaslabs LTD)

Room: 503/1-001 - Council Chamber Modern Java builds have become complex, opaque, and hard to reason about. Build tools often hide their logic behind bespoke Domain-Specific Languages (DSLs), made even harder to follow through layers of plugins. Mill takes a different approach: a fast, comprehensible, and fully programmable build tool based on Scala’s object-oriented and functional capabilities, where your build definition is idiomatic code you’re used to, not arcane configuration. In this talk, we’ll explore how Mill’s task-graph model, composable modules, and source-level transparency give developers precise control and deep insight into their builds. We’ll look at practical examples relevant to Spring Boot projects, including dependency management and pre-processor/annotation-processor workflows. We’ll then push Mill to its limits by looking at the complexity of the Android build process, showing how Mill is able to support even the most complex build configurations. Attendees will leave with a clear understanding of how Mill differs conceptually from Gradle and Maven, why its explicitness and readability matter for large organisations like CERN, and how to leverage Mill’s power to make Java, Spring Boot, Kotlin, and any other sophisticated build configurations more comprehensible and user-friendly.