title: Java sub-module error creating shaded jar
body: <p>I just created a new module in my Dropwizard Project and when I run <br></p>
  
  <pre><code>mvn install
  </code></pre>
  
  <p>I receive the following Exception:</p>
  
  <pre><code>Failed to execute goal org.apache.maven.plugins:maven-shade-plugin:1.6:shade (default) on project justfortest: Error creating shaded jar: null: NullPointerException -&gt; [Help 1]
  org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-shade-plugin:1.6:shade (default) on project justfortest: Error creating shaded jar: null
  </code></pre>
  
  <p>I did not find anything relevant about it on the internet. Can someone tell me something about it?</p>