title: what does Maven -> Update Project... exactly?
body: <p>I am getting really frustrated about this one:</p>
  
  <p>I am using an maven project, using jdbc with <em>eclipselink</em>. <code>mvn install</code> works as intended. Until I have to change the PW in the persistence.xml. When I do an <code>mvn clean</code> and afterwards <code>mvn install</code> the project is broken and the wrong (old) persistence.xml is still in use. In eclipse I have to do <code>maven -&gt; update project</code> (using m2e addon) and <code>mvn install</code> works suddenly again.</p>
  
  <p><strong>Now my problem:</strong> On the deployment server I am using command line scripting and I found no <code>mvn XYZ</code> equivalent for the m2e functionality...</p>
  
  <p>Is there some equivalent?</p>
  
  <p><strong>Explicit scenario:</strong></p>
  
  <p>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 <em>eclipselink</em>. I can deploy locally (<code>mvn install</code>) but after I run <code>mvn clean</code> and change the password in <code>persistence.xml</code> <code>mvn install</code> isn't possible anymore. I just get <code>classDefNotFound Persistor</code> in the tests because it static initialize the <em>EntityManager</em> which can't connect cause of the new <code>persistence.xml</code> -- or at least it's my opinion, because the stacktrace is not really helpful. But, after <code>maven -&gt; update project...</code> in eclipse on the project, <code>mvn install</code> works again and the new password is taken (tests run!).</p>
  
  <p>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.</p>
  
  <p><strong>SOLUTION:</strong>
  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.</p>