title: Can maven parent project include a module at same directory level
body: <p>I am working in an established codebase with an existing standalone pom.xml.</p>
  
  <p>Th intention is to incorporate a child project called "hive"  in a subdirectory off of the parent one.  Note: the hive/pom.xml does already exist and it works fine by itself.</p>
  
  <p>So in the parent's pom.xml I added:</p>
  
  <pre class="lang-xml prettyprint-override"><code>   &lt;modules&gt;
        &lt;module&gt;hive&lt;/module&gt;
     &lt;/modules&gt;
  </code></pre>
  
  <p>The problem is I basically lose ability to create the deployable jar from the  parent project. </p>
  
  <pre><code> stephenb@gondolin:/shared/git2/etl$ mvn package assembly:single
  [INFO] Scanning for projects...
  [INFO] ------------------------------------------------------------------------
  [ERROR] FATAL ERROR
  [INFO] ------------------------------------------------------------------------
  [INFO] Error building POM (may not be this project's POM).
  
  
  Project ID: com.myco.etl:etl
  POM Location: /shared/git2/etl/pom.xml
  Validation Messages:
  
      [0]  Packaging 'jar' is invalid. Aggregator projects require 'pom' as packaging.
  
  
  Reason: Failed to validate POM for project com.myco.etl:etl at /shared/git2/etl/pom.xml
  
  
  [INFO] ------------------------------------------------------------------------
  [INFO] Trace
  org.apache.maven.reactor.MavenExecutionException: Failed to validate POM for project com.myco.etl:etl at /shared/git2/etl/pom.xml
      at org.apache.maven.DefaultMaven.getProjects(DefaultMaven.java:404)
      at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:272)
      at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:138)
      at org.apache.maven.cli.MavenCli.main(MavenCli.java:362)
      at org.apache.maven.cli.compat.CompatibleMain.main(CompatibleMain.java:60)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  </code></pre>
  
  <p>It seems that maven wants me to create a parent pom that basically does nothing except define the dependency modules.</p>
  
  <p>Well I can create a new pom.xml.  But what I cannot do is to push the existing project files into a new subdirectory.</p>
  
  <p>Is there a way to work around this?  E.g. defining a submodule that lives at the same level (not subdir)?  Or some other way to work with the existing dir structure?</p>
  
  <p>thanks</p>
  
  <p>Follow-up:  Based on input that a module can simply be a file in local dir, I 
  created another pom that calls the original one. The original one was renamed to pommod.xml and the new one shown below is called pom.xml.</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"&gt;
      &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
      &lt;groupId&gt;com.myco.etl&lt;/groupId&gt;
      &lt;artifactId&gt;etl&lt;/artifactId&gt;
      &lt;name&gt; ETL Helpers&lt;/name&gt;
      &lt;version&gt;1.0.0-SNAPSHOT&lt;/version&gt;
      &lt;packaging&gt;pom&lt;/packaging&gt;
          &lt;modules&gt;
    &lt;module&gt;appminer&lt;/module&gt;
    &lt;module&gt;pommod.xml&lt;/module&gt;
     &lt;/modules&gt;
  </code></pre>
  
  <p></p>
  
  <p>I ran "mvn compile package"  But still get same error:</p>
  
  <pre><code>Project ID: com.myco:app_miner
  POM Location: /shared/git2/etl/mycopom.xml
  Validation Messages:
  
  [0]  Packaging 'jar' is invalid. Aggregator projects require 'pom' as packaging.
  
  
  Reason: Failed to validate POM for project com.myco:app_miner at /shared/git2/etl/myco/pom.xml
  </code></pre>