With STS 2.8.0, we have upgraded m2eclipse to be version 1.0. However, this can cause a bit of trouble with existing projects. I wrote a blog on this a couple of months ago.
http://blog.springsource.org/2011/10/18/upgrading-maven-integration-for-springsource-tool-suite-2-8-0/
Essentially, the new architecture for m2eclipse requires that each maven plugin you use must be mapped to one Eclipse plugin to handle the plugin's execution inside of Eclipse. This obviously causes problems since not every maven plugin author has the knowledge or time to create also create and maintain an Eclipse plugin.
By marking the plugin as ignored, you are saying that the plugin should never be executed inside of Eclipse (implying that whenever you need it to be executed, you will do so from the command line). Once marked as ignored
, you can then change it to execute
, which means that it should always be executed whenever the associated lifecycle is performed in Eclipse. This may cause performance problems, and so only do it if you know the risks.
If all this is too much for you, then STS provides a downgrade option to revert to an older version of m2eclipse. Go to the Dashboard extensions page. Unfortunately, you will have to manually revert all changes to your .project and .classpath files (we provide an auto-upgrade mechanism, but not a downgrade mechanism...presumably everything is in version control).
Any questions or problems should be sent to the STS forums:
http://forum.springsource.org/forumdisplay.php?32-SpringSource-Tool-Suite