title: sbt assembly failure with spark-cassandra-connector
body: <p>I'm fairly new to the Scala environment. I am receiving a <code>deduplicate</code> error while trying to assemble a Scala Spark job with the DataStax connector. I'd appreciate any advice as to what could resolve this issue.</p>
  
  <p>My System:</p>
  
  <ul>
  <li>Latest Scala (2.11.7) installed via brew</li>
  <li>Latest Spark (2.10.5) installed via brew </li>
  <li>Latest SBT (0.13.9) installed via brew</li>
  <li><a href="https://github.com/sbt/sbt-assembly" rel="nofollow">SBT Assembly</a> plugin installed</li>
  </ul>
  
  <p>My <code>build.sbt</code>:</p>
  
  <pre><code>name := "spark-test"
  
  version := "0.0.1"
  
  scalaVersion := "2.11.7"
  
  // additional libraries
  libraryDependencies += "org.apache.spark" %% "spark-core" % "1.6.0" %     "provided"
  libraryDependencies += "com.datastax.spark" %% "spark-cassandra-connector" % "1.5.0-M3"
  </code></pre>
  
  <p>Console:</p>
  
  <pre><code>$ sbt assembly
  ...
  [error] 353 errors were encountered during merge
  java.lang.RuntimeException: deduplicate: different file contents found in the following:
  /Users/bob/.ivy2/cache/io.netty/netty-all/jars/netty-all-4.0.29.Final.jar:META-INF/io.netty.versions.properties 
  ... 
  </code></pre>