What is org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER and how do I make it work in IntelliJ?
<p>I have a Java codebase that was written with Eclipse that I am trying to work with in IntelliJ.
The codebase consists of about 20 Java packages built alongside each other as separate projects. (There are about twenty directories, each containing a <code>.classpath</code> and <code>.project</code> file.) They have dependencies on each other. Presumably everything builds just fine in Eclipse.</p>

<p>I had IntelliJ import these from the Eclipse build format. It mostly seemed to work except that <code>Project Settings -&gt; Modules -&gt; Dependencies</code> shows that many projects have an unresolved dependency on <code>org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER</code>. This appears to come from the following entries in the <code>.classpath</code> files:</p>

<pre class="lang-xml prettyprint-override"><code>&lt;classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER"&gt;
    &lt;attributes&gt;
        &lt;attribute name="maven.pomderived" value="true"/&gt;
        &lt;attribute name="org.eclipse.jst.component.nondependency" value=""/&gt;
    &lt;/attributes&gt;
&lt;/classpathentry&gt;
</code></pre>

<p>The packages with this dependency do not build in IntelliJ because they can't resolve the dependencies on the other packages.</p>

<p>I suspect that <code>org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER</code> is some Eclipse-specific trickery that doesn't translate to a different IDE, but I can't figure out exactly what is going on here.</p>

<p>What is <code>org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER</code>? Do I have to do anything special to a build environment that uses it to make it work outside Eclipse?</p>

<p><em>IntelliJ Ultimate 2016.1.2, Java 1.8.0_91, OS X 10.11.5</em></p>

<hr>

<p>I worked around this problem by going into Project Settings->Modules and manually adding module dependencies between my various projects until everything built. Tedious but effective.</p>

<p>I'm leaving this question up here, though, because a short definition of <code>org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER</code> would still have been helpful to me.</p>