title: Does a setting in Eclipse propagate to Maven?
body: <p>I've imported a Maven project into Eclipse but I'm still unsure how Maven and Eclipse really work together.</p>
  
  <p>For example, Eclipse just changed my .classpath file when I copied and pasted a source folder from one Module to another in an attempt to solve <a href="https://stackoverflow.com/questions/27388111/can-google-app-engine-modules-share-source-code-just-like-maven-modules">Can Google App Engine Modules share source code just like Maven Modules?</a>:</p>
  
  <p><em>Eclipse added this to .classpath when I copied/pasted source code I want duplicated across modules/projects:</em></p>
  
  <pre><code>&lt;classpathentry kind="src" path="/nbsocialmetrics-backend"/&gt;
  </code></pre>
  
  <p>Eclipse didn't make any changes to my POM.xml files though.  Eclipse seems happy with the .classpath change it made for me, I don't have any compilation warnings for any of the related projects/modules.  But <code>mvn clean install</code> at the top-level of my project is complaining about a lot of missing dependencies.</p>
  
  <p>Am I correct in assuming a command-line Maven command such as <code>mvn clean install</code> won't look at the Eclipse .classpath file?</p>
  
  <p>Doesn't Maven only rely on the following?</p>
  
  <ol>
  <li>POM.xml files</li>
  <li>Repositories such as the Maven Central repository</li>
  <li>Command line arguments passed to <code>mvn</code></li>
  <li>Source code/resources/etc. (the stuff you want to build, not meta data such as .classpath)</li>
  </ol>
  
  <p>If I'm correct in understanding this, why would Eclipse allow me to make changes that aren't correct for a Maven project I've imported?  What types of Eclipse changes are actually safe to make--in other words what types of changes that I make in Eclipse will actually get reflected at the time I go to execute <code>mvn clean install</code> at the command line?</p>
  
  <p>As another example, I'm trying to use Eclipse's WindowBuilder Editor for some GWT in one of my modules (J2EE/Maven sense of 'module' not GWT sense of 'module').  As I'm looking to ensure I have the right version of WindowsBuilder to resolve <a href="https://stackoverflow.com/questions/27384033/error-no-gwt-module-found-for-maven-project-imported-into-eclipse">Error &quot;No GWT module found&quot; for Maven project imported into Eclipse</a>, should I be looking at Eclipse plugin settings or Maven POM.xml settings?  Eclipse, in this case, right?</p>
  
  <p>Thanks for helping me understand.</p>