Here’s a quick task that will let you know if your dependencies need to be updated, a la mvn versions:display-dependency-updates. It’s actually a bit longer than most Gradle snippets, so I suspect there’s a way to express it more succinctly. The irony, of course, is that it relies on the Maven central repo to determine whether or not any of your dependencies are out of date.

// Find any 3rd party libraries which have released new versions
// to the central Maven repo since we last upgraded.
task checkLibVersions << {
  def checked = [:]
  allprojects {
    configurations.each { configuration ->
      configuration.allDependencies.each { dependency ->
        def version = dependency.version
        if(!version.contains('SNAPSHOT') && !checked[dependency]) {
          def group = dependency.group
          def path = group.replace('.', '/')
          def name = dependency.name
          def url = "http://repo1.maven.org/maven2/$path/$name/maven-metadata.xml"
          try {
            def metadata = new XmlSlurper().parseText(url.toURL().text)
            def versions = metadata.versioning.versions.version.collect { it.text() }
            versions.removeAll { it.toLowerCase().contains('alpha') }
            versions.removeAll { it.toLowerCase().contains('beta') }
            versions.removeAll { it.toLowerCase().contains('rc') }
            def newest = versions.max()
            if(version != newest) {
              println "$group:$name $version -> $newest"
            }
          } catch(FileNotFoundException e) {
            logger.debug "Unable to download $url: $e.message"
          } catch(org.xml.sax.SAXParseException e) {
            logger.debug "Unable to parse $url: $e.message"
          }
          checked[dependency] = true
        }
      }
    }
  }
}

Have I missed any?

• Maven 2.0.2 (January 2006)
• Maven 2.0.3 (March 2006)
• Maven 2.0.4 (April 2006)
• …zzzz…zz…zzzzzz…
• Maven 2.0.5 (February 2007)
• Maven 2.0.6 (April 2007)
• Maven 2.0.7 (June 2007)
• Maven 2.0.8 (August 2007 [tentative])

As you can see, nothing much happened for about a year there.

In his announcement on The Server Side, Jason mentions the team’s intention to release monthly maintenance releases from here on out. I’ve also noticed increased activity on a couple of the issues I’m watching in Maven’s issue tracker, including features slated for the 2.1 release. I really like Maven 2, and I’m glad to see these signs of resurgent activity.

Congratulations, guys!

Lesson the first: don’t point your JAVA_HOME environment variable to a path which includes spaces. This was a good rule of thumb back in 1997, but come on! Ten years later, and we’re still dealing with these issues? The Maven batch file is full of double-quoted variables and values, but apparently it’s just an effort to instill a false sense of security in unwary developers.

Lesson the second: do not, under any circumstances, add a trailing slash to your MAVEN_HOME environment variable. Doing so (ie, using “C:\java\maven-1.0.2\” instead of “C:\java\maven-1.0.2″) will cause Maven to throw the Java usage message at you, instead of doing something useful like, say, compiling your project.

It’s too bad that Mergere seems to be having some trouble. Both versions of Maven could really use the polish that comes with a professional [read: for money] operation a la JBoss…

UPDATE: Enter Sonatype!