title: How to get nested map from Cassandra Result Set
body: <p>I have a Cassandra table like this: </p>
  
  <pre><code>create table Engine (
      primayval text,
      Dataval  map&lt;text,&lt;map&lt;text, double&gt;&gt;,
      PRIMARY KEY (tradeddate)
  );
  </code></pre>
  
  <p>How can I retrieve this in a Java nested map <code>Map&lt;String,Map&lt;String,Double&gt;&gt;</code> using <code>ResultSet-&gt; getMap()</code> without JSON conversion?</p>