title: Why Maven assembly works when SBT assembly find conflicts
body: <p>The title could also be: <br>
  <strong>What are the differences between Maven and SBT assembly plugins.</strong></p>
  
  <p>I have found this to be an issue, while migrating a project from Maven to SBT.</p>
  
  <p>To describe the problem I have created an example project with dependencies that I found to behave differently, depending on the build tool.</p>
  
  <p><a href="https://github.com/atais/mvn-sbt-assembly" rel="noreferrer">https://github.com/atais/mvn-sbt-assembly</a></p>
  
  <hr>
  
  <p>The only dependencies are (sbt style)</p>
  
  <pre><code>"com.netflix.astyanax" % "astyanax-cassandra" % "3.9.0",
  "org.apache.cassandra" % "cassandra-all" % "3.4",
  </code></pre>
  
  <p>and what I do not understand is, why <code>mvn package</code> creates the fat jar successfully, while <code>sbt assembly</code> gives conflicts:</p>
  
  <pre><code>[error] 39 errors were encountered during merge
  [error] java.lang.RuntimeException: deduplicate: different file contents found in the following:
  [error] /home/siatkowskim/.ivy2/cache/org.slf4j/jcl-over-slf4j/jars/jcl-over-slf4j-1.7.7.jar:org/apache/commons/logging/&lt;some classes&gt;
  [error] /home/siatkowskim/.ivy2/cache/commons-logging/commons-logging/jars/commons-logging-1.1.1.jar:org/apache/commons/logging/&lt;some classes&gt;
  ...
  [error] /home/siatkowskim/.ivy2/cache/com.github.stephenc.high-scale-lib/high-scale-lib/jars/high-scale-lib-1.1.2.jar:org/cliffc/high_scale_lib/&lt;some classes&gt;
  [error] /home/siatkowskim/.ivy2/cache/com.boundary/high-scale-lib/jars/high-scale-lib-1.0.6.jar:org/cliffc/high_scale_lib/&lt;some classes&gt;
  ...
  </code></pre>