what does Maven -> Update Project... exactly?

I am getting really frustrated about this one: I am using an maven project, using jdbc with eclipselink. `mvn install` works as intended. Until I have to change the PW in the persistence.xml. When I do an `mvn clean` and afterwards `mvn install` the project is broken and the wrong (old) persistence.xml is still in use. In eclipse I have to do `maven -> update project` (using m2e addon) and `mvn install` works suddenly again. Now my problem: On the deployment server I am using command line scripting and I found no `mvn XYZ` equivalent for the m2e functionality... Is there some equivalent? Explicit scenario: I am developing on my local machine (osx/win7) in an maven project imported in eclipse. I have a JPA Persistence interface which encapsulate the database connection which is realized via eclipselink. I can deploy locally (`mvn install`) but after I run `mvn clean` and change the password in `persistence.xml` `mvn install` isn't possible anymore. I just get `classDefNotFound Persistor` in the tests because it static initialize the EntityManager which can't connect cause of the new `persistence.xml` -- or at least it's my opinion, because the stacktrace is not really helpful. But, after `maven -> update project...` in eclipse on the project, `mvn install` works again and the new password is taken (tests run!). When I want to deploy the project on a remote machine (debian, commandline) I can't ´mvn install` the pulled project, cause after I changed the password in persistence.xml for deployment, it's again the wrong persistence.xml or at least some cached used. I hope that make it a bit more clear. SOLUTION: Make sure persistence.xml is placed in src/main/resources/META-INF and not elsewhere. m2e catches persistence.xml from wrong places (in my case, src/main/java/META-INF). So it was basically just a wrong project structure.