Maven is a pattern-based build framework for Java and J2EE projects; more than just scripting builds for arbitrary projects, Maven knows about J2EE, Struts, Hibernate, etc. and has a prescribed way of structuring and organizing a project from its moment of creation through testing, packaging, and deployment. The Maven authors (in the book "Better Builds With Maven",) describe their project:
Maven encompasses a set of build standards, an artifact repository model, and a software engine that manages and describes projects. It defines a standard life cycle for building, testing, and deploying project artifacts. It provides a framework that enables easy reuse of common build logic for all projects following Maven's standards. The Maven project at the Apache Software Foundation is an open source community which produces software tools that understand a common declarative Project Object Model (POM).The Maven folks have an agreement with ibiblio, which hosts all of the files related to supported dependencies, such that a default installation can remotely populate all of the files it needs from a known repository (a mechanism reminiscent of Gem except in a build-centric way). With so much built-in magic, Maven-based projects can be almost deceptively easy to start but have enough going on under the hood to warrant a 292 page book. Given its ambitious scope, Maven has engendered some pretty strong feelings in the past that the development team has worked to address:
Maven's best practices often don't address corporate real world headaches. Even when I agree with them I bump up against the problems inherent with what an existing corporate practise and/or current tool sets.Just this week, Matt Raible reported on his experience migrating AppFuse from Ant to Maven:
One of the most interesting things about moving to Maven is we were easily able to make AppFuse more like a framework than a project starter kit. We thought this is what most folks wanted - especially the ability to upgrade a project to the latest version of AppFuse. While some folks wanted this, it seems like most folks liked the full-source version that was a pain-in-the-ass to upgrade. I don't blame them.Since the release of Maven 2, updates (up to the recent 2.0.6 release) have consistently provided bug fixes and incremental improvements to the usability of the core engine. The repository is also frequently updated with the most up-to-date support for common dependencies like Spring and Tomcat, as well as less common ones like openid4java and mule. Earlier this year, lead committers Jason Van Zyl and John Casey left Mergere, a leading sponsor and commercial provider of support for Maven, but continue to participate actively in development.
Of course, the real benefits of moving to Maven are elsewhere. We've seen quite an uptick on the mailing list in the last few months. There's tools cropping up and I've gotten quite a few inquiries about training (yes, I do have a 3-day course on Spring, Hibernate, Ajax, Maven and AppFuse). To me, AppFuse 2.x seems more complicated than 1.x, but it seems the community thinks otherwise. Judging from the increased amount of developer activity on the project, developers seem more interested in a Maven-based system too. Then again, we are making Maven work!