title: Why Maven changes Eclipse project preferences?
body: <p>First of all, I'm using Ubuntu 12.04, Eclipse Juno with embebbed maven 3.0.4 (m2eclipse) and I have to work in a legacy project which I got from a SVN repositroy.</p>
  
  <p>I'm stuck in a sort of configuration problem with Maven and Eclipse.</p>
  
  <p>At the first time I did a Maven > Update project and I got an "Unknown Error" of "Maven Java EE Configuration Problem" type. I checked my project's properties and I've realized that java compliance level is set to 1.5 but I have 1.6 JRE activated. Well, I've changed to 1.6 version (in Java Facet too), but when I do a Maven > Update project, my project's properties are restored to default (a.k.a. 1.5 version), and the Unknown error persists.</p>
  
  <p>My pom.xml file seems to be ok, and I also try to update project with an empty pom.xml (just with modelVersion, groupId, artifactId, version, name and url tags) and I always get the same error.</p>
  
  <p>I'm really stuck. Someone has a clue?</p>