m2eclipse says "Missing artifact" but I can build from cmdline!

If Dependency management is enabled when the above problems occur in Eclipse you can Project > Maven > Disable Dependency Management and then \Project > Maven > Enable Dependency Management. This normally remove any dependency errors in the pom.xml.

Also do as @Nishant indicated in his answer above after the above steps to complete the projects dependencies.

You may need to to tell Eclipse to force update:

Project -> Maven -> Update Maven Project

and then make sure you have selected:

Force Updates of Snapshots/Releases

this happens when mvn install copies some jar files into Maven repository and Eclipse had checked this repo BEFORE this jar has been copied there.

right click on your project > Maven > Update Dependencies

then

right click on your project > Maven > Update Project configuration

Assuming you M2Eclipse plugin is installed correctly this should solve the issue. Also, check if there is an option right click project > Maven > Enable dependency Management select that.