Title: An unexpected journey among modules Abstract: So Java 9 has modules. As a member of the Expert Group, i've toured the french speaking JUGs to explain what Java modules are, and gather feeling and remarks from the community. One problem i face is that existing build tools like Maven or Gradle are updated at their own pace and are currently more focused on working on Java 9 than how to seamlessly support the new module environment (this is not a criticism they have a huge base of existing users). In a train after a presentation at one JUG, i flip out and start to develop my own build tool, pro (for programatic build tool) [1]. In this talk, i will explain why you have to compile several modules together even if the resulting module graph has no cycle, how a build tool can help you to test modules, how to integrate non modular jars from maven central and how to implement some vanity features like a plugin system, a REPL for creating the build configuration or use the new linker to create a static image. [1] https://github.com/forax/pro Bio: Remi Forax is Assistant Professor at UPEM (Paris East University), a Java Champion and an active participant of several OpenJDK projects. Moreover, he is/was member of several JCP expert groups that shape the recent versions of Java (invokedynamic, lambdas, modules). His research area focused on the implementation of dynamic languages on top of runtime environments, in that context, he is one of the maintainers of the open source project ASM, a bytecode instrumentation tool used by frameworks like Maven, Spring or Weld.