Problem
Eclipse doesn’t see Maven dependencies in Maven based Adobe AEM/CQ5 projects and auto completion doesn’t work either.
Solution
Close Eclipse and run the following command from shell
mvn -Declipse.workspace=<path/to/eclipse/workspace> eclipse:add-maven-repo
after that, go to your folder with the project you want to make Maven dependencies working and run
mvn eclipse:eclipse
After that, simply start Eclipse and everything should work fine.