title: How to convert Dataset into JavaPairRDD?
body: <p>There are methods to convert Dataset to JavaRDD .</p>
  
  <pre><code>Dataset&lt;Row&gt; dataFrame;
  JavaRDD&lt;String&gt; data = dataFrame.toJavaRDD();
  </code></pre>
  
  <p>Is there any other ways to convert Dataset into <code>javaPairRDD&lt;Long, Vector&gt;</code>?</p>