When should we move to Maven 3?

Question

Our project badly needs to move to Flexmojos4 to get a fix, but this requires Maven 3. Our project makes extensive use of Maven and we really love it, but have configured it very heavily. Between a dozen modules we probably have 50+ pages of XML configuration.

We also use Eclipse and make heavy use of the M2Eclipse plug-in. We also use the following Maven plug-ins:

Resources BuildNumber SQL Hibernate3 Flexmojos Assembly Jetty Cargo JAR/WAR

and several others. Reading this blog:

http://www.sonatype.com/people/category/m2eclipse/

Makes me feel like Eclipse Indigo is when it'll all work together. When should we invest the time to make the move?

Answer 1

In fact "the move" should actually consist of simply upgrading the maven installation / m2eclipse only. Maven 3 is almost completely backward-compatible with Maven 2.

Check the compatibility notes to make sure you are not breaking something that will need a lot to fix.

Answer 2

(...) Makes me feel like Eclipse Indigo is when it'll all work together. When should we invest the time to make the move?

No, you can use Maven 3 and Eclipse 3.5 / 3.6 now (I don't even remember when I started to use Maven 3).

First, Maven 3 is backward compatible (see Maven 3 - Worth it?) so, as I commented in Should I upgrade to Maven 3?:

why don't you just try it? There is nothing to "upgrade", just install Maven 3 along your Maven 2 install, change your PATH settings and try it on an existing POM.

Second, m2eclipse 0.10 uses Maven 3 as embedded version for a long time (for dependency resolution even if you declare an "external" install) and is thus already Maven 3 ready. Just add the final version of Maven 3.0 as external install and there you go.

To sum up: Maven 3 is totally usable, I almost had nothing to change in my poms (only a few things to fix them thanks to the better reporting of Maven 3), it just works inside Eclipse and it builds faster. Just try it.

PS: I use the script attached to MNG-2730 to switch between the maven versions I have on my machine, if required.