The Apache Software Foundation has posted the third beta of Maven 2.0, an open source build tool for Java that's more declarative and less procedural than Ant. According to the Maven site,
Maven 2.0 will feel very different to a Maven 1.0 user - and perhaps a little strange. But it is a lot simpler to work with! The key changes from Maven 1.0 are:
- Faster and smaller - The Maven core no longer uses Ant, Jelly or Xerces making it much smaller, has fewer dependencies and is perfect for embedding in other tools.
- Defined build lifecycle - No more
prereqs,preGoalsandpostGoals. The build is a series of well defined phases. This also means that the normal goal names are not used -compile,testandinstallwork for any project type.- Built-in multiple project handling - Use the same goals on a set of projects, and aggregate the results.
- Improved
SNAPSHOThandling - Snapshots are now checked for updates only once per day by default - though can be configured to be once per build, on a particular interval, or never. A command line option can force a check - making it more like updating from an SCM.- No more properties files - All plugins are now configured from the POM (which is now called
pom.xml).- No more
maven.xml- Plugins are now easier to build and integrate, and are the only way to script your builds. (Note that additions may later be made to the POM to allow simple things that scripting was used for, such as goal aliasing).- No more Jelly - Plugins are primarily written in Java, though there are providers for other scripting languages. This release includes support for Marmalade, a scripting framework that supports an XML syntax similar to Jelly which can be used to integrate Ant tasks and has a Jelly compatibility layer.
- Improved repository layout - Maven 2.0 supports both the existing layout, and an improved repository layout that has deeper, partitioned structure making it easier to browse.
" The elimination of Jelly in favor of Java should be a real improvement. Extending Maven 1.0 is vastly too difficult. If plug-ins exist to do what you want, it's no big deal. If not, you really don't want to try writing your own. "This release is considered stable with a feature set comparable to Maven 1.0. Further betas and the final are expected to be backwards compatible, with a primary goal of bugfixes, usability improvements, and documentation."