One would think that if you explicitly specify the url of a maven plugin dependency in maven.xml, it will be used to download the plugin. But it doesn't! Worse still, when maven couldn't download the specified plugin, it would complain saying it couldn't find the plugin from the specified url, but in fact it always by default download from

    http://www.ibiblio.org/maven/<groupId>/plugins/<artifactId>-<version>.jar

Isn't this misleading and pretty counter-intuitive ?

To override this behavior, you can specify a list of remote sites via "maven.repo.remote" in project.properties.

For example:

    maven.repo.remote = http://www.ibiblio.org/maven/, http://<myurl>

More details can be found here.